hull speed of a catamaran

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Catamaran Hull Design

• Post author By Rick
• Post date June 29, 2010
• 2 Comments on Catamaran Hull Design

Part 1: Notes from Richard Woods

Since the America’s Cup experimented with going multihull, there’s been a lot of interest in catamaran performance and the catamaran hull designs that define performance. Many guys are investigating whether to buy a catamaran or design and build their dream boat. Let it be said here that building a large catamaran is not for the faint of heart. People begin building 100s of boats a year, yet few are ever completed, as life always seems to have a way of interfering with a good boat build. 

Never the less, since the rest of this website is about selecting and buying a boat , it only seems fair to have at least one webpage that covers catamaran design. This page contains notes on boat hull design goals and an accompanying page from Terho Halme has mathematical formulas used in actual catamaran hull design. It has become a popular research stop and an important reference to the catamaran design community.

The content of this page was reproduced from the maestro of Catamaran designs, renown British naval architect, Richard Woods, who not only designs catamarans, he sails them across oceans…. repeatedly. He has a lot to say on the subject of catamaran hull design.

“…When it’ all said and done, the performance of a sailing catamaran is dependent on three primary specs: length, sail area and weight. If the boat is longer it generally means it’ a faster boat. If she has more sail area, it means she’ a faster boat and if she’ light it means she’ a faster boat.  Of course, there are limits: Too much sail area capsizes the boat in brisk winds. If the boat is designed too light, she will not take any kind of punishment. Too slim a hull design and the boat becomes a large Hobie Cat capable of only carrying your lunch. Of course, too long and large and you’d have to be Bill Gates to afford one. Then there are lot of additional and very important factors like underwater hull shape, aspect ratios of boards and sails, wet deck clearance, rotating or fixed rigging and so on….” Richard Woods

All Catamarans are not equal, but all sailboats have two things in common: They travel on water and they’re wind powered, so the Catamaran design equations in the 2nd part should apply to every catamaran from a heavy cruising Cat to a true ocean racer.

Richard Wood’s comments on catamaran design:

We all know that multihulls can be made faster by making them longer or lighter or by adding more sail. Those factors are the most important and why they are used as the basis of most rating rules. However using just those figures is a bit like determining a cars performance just by its hp and curbside weight. It would also imply that a Tornado would sail as fast forwards as backwards (OK, I know I just wrote that a Catalac went faster backwards than forwards)

So what next?? Weight and length can be combined into the Slenderness Ratio (SLR). But since most multihulls have similar Depth/WL beam ratios you can pretty much say the SLR equates to the LWL/BWL ratio. Typically this will be 8-10:1 for a slow cruising catamaran (or the main hull of most trimarans), 12-14:1 for a performance cruiser and 20:1 for an extreme racer.

So by and large faster boats have finer hulls. But the wetted surface area (WSA) increases proportionately as fineness increases (for a given displacement the half orange shape gives the least WSA) so fine hulls tend to be slower in low wind speeds.

The most important catamaran design hull shape factor, is the Prismatic Coefficient (Cp). This is a measure of the fullness of the ends of the hull. Instinctively you might think that fine ends would be faster as they would “cut through the water better”. But in fact you want a high Cp for high speeds. However everything is interrelated. If you have fine hulls you can use a lower Cp. Most monohulls have a Cp of 0.55- 0.57. And that is about right for displacement speeds.

However the key to Catamaran design is you need a higher Cp if you want to sail fast. So a multihull should be at least 0.61 and a heavy displacement multihull a bit higher still. It is difficult to get much over 0.67 without a very distorted hull shape or one with excessive WSA. So all multihulls should have a Cp between 0.61 and 0.65. None of this is very special or new. It has been well known by naval architects for at least 50 years.

There are various ways of achieving a high Cp. You could fit bulb bows (as Lock Crowther did). Note this bow is a bit different from those seen on ships (which work at very specific hull speeds – which are very low for their LOA). But one problem with them is that these tend to slam in a seaway. 

Another way is to have a very wide planing aft section. But that can increase WSA and leads to other problems I’ll mention in a minute. Finally you can flatten out the hull rocker (the keel shape seen from the side) and add a bustle aft. That is the approach I use, in part because that adds displacement aft, just where it is most needed.

I agree that a high Cp increases drag at low speeds. But at speeds over hull speed drag decreases dramatically on a high Cp boat relative to one with a low Cp. With the correct Cp drag can be reduced by over 10%. In other words you will go 10% faster (and that is a lot!) in the same wind and with the same sails as a boat with a unfavorable Cp. In light winds it is easy to overcome the extra drag because you have lots of stability and so can fly extra light weather sails.

The time you really need a high Cp boat is when beating to windward in a big sea. Then you don’t have the stability and really want to get to your destination fast. At least I do, I don’t mind slowly drifting along in a calm. But I hate “windward bashing”

But when you sail to windward the boat pitches. The sea isn’t like a test tank or a computer program. And here I agree with Evan. Immersed transoms will slow you down (that is why I use a narrower transom than most designers).

I also agree with Evan (and why not, he knows more about Volvo 60 design than nearly anyone else on the planet) in that I don’t think you should compare a catamaran hull to a monohull, even a racing one. Why chose a Volvo 60/Vendee boat with an immersed transom? Why not chose a 60ft Americas Cup boat with a narrow out of the water transom?? 

To be honest I haven’t use Michelet so cannot really comment. But I have tested model catamarans in a big test tank and I know how inaccurate tank test results can be. I cannot believe that a computer program will be better.

It would be easy to prove one way or the other though. A catamaran hull is much like a frigate hull (similar SLR, L/B ratios and Froude numbers) and there is plenty of data available for those. There is also a lot of data for the round bilge narrow non planing motorboats popular in the 1930’-50’s which again are similar to a single multihull hull.

One of the key findings I discovered with my tank test work was just how great the drag was due to wave interference between the hulls. Even a catamaran with a modern wide hull spacing had a drag increase of up to 20 % when compared to hulls at infinite spacing. One reason why just flying a hull is fast (the Cp increases when you do as well, which also helps). So you cannot just double the drag of a single hull and expect to get accurate results. And any speed prediction formula must include a windage factor if it is to give meaningful results.About 25 years ago we sailed two identical 24ft Striders next to each other. They were the same speed. Then we moved the crew of one boat to the bow. That boat IMMEDIATELY went ½ knot faster. That is why I now arrange the deck layout of my racing boats so that the crew can stay in front of the mast at all times, even when tacking or using the spinnaker.

I once raced against a bridge deck cabin catamaran whose skipper kept the 5 crew on the forward netting beam the whole race. He won.

Richard Woods of Woods Designs www.sailingcatamarans.com

• Tags Buying Advice , Catamaran Designers

Owner of a Catalac 8M and Catamaransite webmaster.

2 replies on “Catamaran Hull Design”

I totally agree with what you say. But Uli only talk sailing catamarans.

If only solar power. You need the very best. As limited watts. Hp.

The closer to 1-20 the better.

Closing the hulls to fit in cheaper marina berth. ?

You say not too close. But is that for sailing only.

Any comment is greatly appreciated

Kind regards Jeppe

Superb article

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Hull Speed Calculator

Table of contents

Welcome to the hull speed calculator . If you've ever seen a boat go so fast that its nose started rising, then you've seen the concept of hull speed in action. In this article, we'll explain what hull speed is and what it means for a ship's design. Later, we'll show you how to calculate hull speed with the hull speed formula, so that you can work out how to calculate hull speed for your own boat.

What is hull speed?

Hull speed is the speed at which a vessel with a displacement hull must travel for its waterline to be equal to its bow wave's wavelength. A displacement hull travels through water, instead of on top of it as a planing hull (like a kiteboard ) would, thereby displacing water with its buoyancy as it sails. The pressure that this displacement exerts on the water creates a wave; this wave is known as the vessel's bow wave . A slow-moving boat's bow wave might make small waves, but, as the boat sails faster, the bow wave's wavelength λ \lambda λ grows. When the wavelength meets the waterline length (that's also when the bow wave's first and second crests are at opposite tips of the waterline), the boat is said to be traveling at hull speed. Take a look at the picture below to see what we mean:

Why does hull speed matter?

Although it's not perfect, hull speed remains a useful concept that can help us answer questions about how fast a sailboat can go, and the optimal amount of thrust you need to keep a boat moving forward.

A boat's hull speed limits how fast it can travel efficiently. When traveling at hull speed, the boat's bow wave and stern wave have synchronized and constructive interference occurs, which allows the boat to move very efficiently. However, at speeds greater than hull speed, a vessel's nose automatically starts rising as the vessel tries to climb its bow wave. This process is called planing , and it wastes lots of energy. Trying to move faster than the hull speed will therefore require more and more thrust (whether that comes from sails, rowing, or engines) in exchange for smaller and smaller gains in speed as more energy is wasted angling the boat upwards. Hull speed can therefore be said to impose a flat limit on how fast a sailboat can go.

Shortcomings of hull speed

Although the physics behind hull speed is sound, it is heavily dependent on the hull's shape. Long and thin hulls with piercing designs can easily break their hull speed without planing. Such hulls are found on:

• Catamarans; and
• Competitive kayaks.

A hull's design can enable it to circumvent the workings of hull speed. It is for this reason that hull speed is not used in present-day ship design; naval institutions nowadays favor more modern measurements of speed-to-length ratio, such as the Froude number .

How to calculate hull speed

The formula for hull speed only needs the length of the vessel's waterline in feet, denoted as L waterline L_\text{waterline} L waterline ​ . With this length, the vessel's hull speed in knots can be calculated with

If you want to instead work out exactly how long your new boat's waterline must be for it to have a certain hull speed, you can invert the formula to obtain

How to use the hull speed calculator

The hull speed calculator is just as easy to use as the formula.

Enter your vessel's waterline length into the first field. This is the length of your boat's hull at the height of the waterline. Your vessel's hull speed will then be calculated and presented in the second field.

You can also use the hull speed calculator backward to work out how long a vessel's waterline must be if you know its hull speed.

You can freely change the units of your measurements without interfering with the hull speed formula.

How can I increase my boat's hull speed without changing its hull?

Load your boat heavier! If you think about a normal displacement hull, it's usually narrower near the bottom than at the deck. So pushing it down with some weight will lengthen the boat's waterline, and so its hull speed is increased. Of course, heavier boats are harder to move, so while your loaded boat now has a higher hull speed, you would need more power to move it.

Waterline length

The length of the ship at its waterline.

The speed at which the ship's waterline length equals its bow wave's wavelength.

Cruising Catamaran Speed! With Examples and Explanation

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One of the most popular cruising vessels is cruising catamarans. Cruising catamarans are popular thanks to their stability and space, but some sailors have concerns about cruising catamarans’ speed. So, how fast are cruising catamarans? 

Sailing cruising catamarans can travel at an average of 9-15 knots and max out around 35 kts. Power Cruising catamarans have a maximum speed of 70 knots but averages around 20-25 kts. How fast a catamaran can go also depends on the load it is carrying, its structural design, and its engine power.

This article explores details of what affects a cruising catamaran’s speed. It also considers how fast sailing and power cruising catamarans can go, along with some of the most rapid cruising catamaran models available today. 

How Is a Cruising Catamaran’s Speed Measured?

To better understand a cruising catamaran’s speed, it is essential to consider how a boat’s speed is measured. Boat speed is measured in knots , which is one nautical mile per hour, (or 1.15 mph). One nautical mile is approximately 1.15 land miles. 

The speed of a catamaran is calculated by a GPS tracker that records the distance sailed every hour. 

How Fast Are Sailing Cruising Catamarans? 

The wind powers sailing cruising catamarans – their speed depends on the speed of the wind. If there is a lot of wind, more wind equals higher a faster boat. However, if there is little to no wind, the catamaran won’t move very fast or very far. 

At about 14-16 knots of wind speed, sailing catamarans can average 9-12 knots . Some high-end sailing catamarans can be even faster. For instance, the Gunboat 62 Tribe can sail up to 36.6 knots when the wind is between 35-45 knots.  

How Fast Are Power Cruising Catamarans?

Unlike sailing catamarans, power catamarans do not rely on the wind to move. Instead, they are powered by fuel (usually diesel). This means that they can travel faster than sailing catamarans and that their speed is more reliable. 

Under light loads the Power catamarans can travel at between 20-25 knots. When the load is higher, power catamarans speed drops to 15-20 knots. 

Some high-end catamarans, such as the Freeman 47, can reach up to 70 knots .

What Affects the Speed of a Cruising Catamaran? 

There are several features of a cruising catamaran that impact its speed. These include: 

• The type of hull. The less the hull is submerged into the water, the faster the catamaran will go. When they are submerged, hulls create drag which slows the velocity of the boat. 
• The beam/length ratio. When a catamaran has a higher surface area (stable base), it can better withstand stronger winds, therefore allowing it utilize more of the wind before needing to reduce sail area.
• The material used to construct and reinforce the vessel. When areas of the catamaran are filled with foam, it decreases the catamaran’s weight while ensuring that stability is maintained. As a result, the catamaran has a lighter weight, making it faster. 
• The type of propellers. Propellers are an essential part of a vessel as they act as brakes, which are necessary to slow down and stop a boat. However, many modern cruising catamarans have folding propellers that reduce the boat’s water resistance when the engine is turned off. As a result, the catamaran can travel faster under sail. 
• The engines. The higher the horsepower of the catamaran’s engine, the faster it can go. Most newer catamarans have two engines which makes them faster than the older, one-engined counterparts. 
• The load of the catamaran. Each catamaran has a load-carrying capacity. If the amount of weight the catamaran has onboard exceeds this capacity, it will “sit” lower in the water and significantly slow down the catamaran’s speed. 
• The sail trim and reef. When sail area is reduced (called reefing), the catamaran slows down (in most situations). Properly trimming the sails will also enhance performance.

In addition, catamarans will be faster downwind . Going downwind removes the headwind and will many times allow you to surf with the waves.

Why Should You Look for a Faster Cruising Catamaran?

The old adage is that “slow and steady” wins the race. However, when it comes to cruising catamarans, many sailors believe the faster, the better. Faster catamarans are preferred because they: 

• Allow the crew to quickly move the catamaran out of bad weather conditions, protect the vessel and passengers on board.
• Allow the captain to more predictably calculate Estimated Time of Arrival (ETA).
• A shorter time spent in bad patches of sea making big ocean crossings safer and more enjoyable.

What Are the Fastest Cruising Catamaran Models? 

Some catamarans have been recognized and won awards for their speed. Some of these models are explored below. 

Freeman 47 (Power)

Freeman catamarans are symmetrical catamarans that have especially been designed to carry a heavy load without sacrificing speed. Released in 2020, the Freeman 47 has quad 450R Mercury outboards that allow it to travel at 70 knots.

In addition to the outboards, many features of the Freeman 47 allow it to move faster. It has a fuel capacity of 1000 gallons (3785 liters) and a maximum power of 1800 HP. 

If you’re interested in purchasing or finding out more about the Freeman 47, register your interest on Freemanboatworks.com . 

Glider SS18 (Power)

The Glider SS18 is a power catamaran that was launched in 2017, after eight years of development. It is powered by 300 BHP supercharged engines that allow it to travel for up to 50 knots. It also has a built-in Stability Control System (SCS), ensuring that the catamaran remains stable and comfortable, even when traveling at top speed. 

To buy or get a quotation for the Glider SS18, visit glideryachts.com . 

ICE Cat 61 (Sail)

The Ice Cat 61 is a luxury catamaran. At 61 feet (18.60 meters) long, it is a large catamaran that has been designed with both speed and stability in mind. While its average cruising speed is 12 knots, it can achieve up to 25 knots. 

The ICE Cat 61 has been designed with carbon and glass fiber – materials that allow the boat to be lighter. It has two engines with 55 HP each and a fuel capacity of 206 gallons (780 liters). 

If you’re interested in an ICE Cat 61, you can learn more at iceyachts.it .

Gunboat 68 (Sail)

At 68 feet (20.8 meters) long, the Gunboat 68 makes for an impressive sight on the open ocean. It averages 20 knots but can reach 30 knots depending on the amount of wind power. 

The Gunboat 68 has been designed by VPLP, also known as the ‘ fastest naval architects in the world .’ It has been designed with large sails, long daggerboards, and material that has lighter weight. This vessel also has retractable rudders, which reduce the boat’s drag. 

To find out more about the Gunboat 68 or register interest in purchasing one, visit Gunboat.com . 

Conclusion 

A catamaran’s speed depends on its design, its load, its type, and on a variety of other factors. However, on average, most sailing catamarans can achieve between 9-15 knots, while power catamarans can, on average, achieve between 20-25 knots. If you are looking to splurge for the best on the market, some power catamarans can reach 50-70 knots. 

If you’re looking to buy a cruising catamaran, make sure you use the information you have gained to assess the speed of the catamaran you are considering. A faster catamaran can make for safer and more exciting sailing. Ultimately, it will make your cruising experience more enjoyable and satisfying. 

Owner of CatamaranFreedom.com. A minimalist that has lived in a caravan in Sweden, 35ft Monohull in the Bahamas, and right now in his self-built Van. He just started the next adventure, to circumnavigate the world on a Catamaran!

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How Fast Do Catamarans Go?

Last Updated by

Daniel Wade

August 30, 2022

‍ Catamarans are known for their speed, and some vessels are fast enough to break world sailing speed records.

Catamarans can go between 15 and 30 knots, with the fastest achieving speeds well in excess of 60 knots. Sailing catamarans are sometimes twice as fast as monohulls and cut through the water with greater efficiency.

In this article, we’ll cover how fast catamarans can go based on factors such as size, sail area, and design category. Additionally, we’ll compare catamaran speeds to monohulls and trimarans and cover the reasons why multi-hull sailboats blow monohulls out of the water.

We sourced the information used in this article from sailing guides and hull speed calculations. Additionally, we sourced information directly from the manufacturers of common catamarans.

Table of contents

‍ Catamaran Speed by Type

Catamaran design can be split into different categories. After all, different vessels are designed for different tasks, as speed isn’t always the most important design consideration.

The fastest type of catamaran is the ultralight racing catamaran. These vessels have extremely narrow hulls and a remarkable planing ability. They’re designed to pierce waves and often achieve speeds in excess of 45 knots or greater, depending on conditions.

The second fastest catamaran variety is the sport catamaran. Sport catamarans often include a fairly good level of creature comforts in the cabin. They’re technically hybrid designs, because they are envisioned as a combination between a racer and a cruiser. Sport catamarans can achieve 30 knots or greater.

Cruising catamarans are designed primarily for safety and comfort. They’re often used for long offshore passages, where speed is important, but comfort is king. Despite their accommodations, cruising catamarans can still achieve a respectable 15 to 20 knots of speed—sometimes 50% faster than similarly-equipped monohulls.

Why are Catamarans So Fast?

Catamarans are remarkable vessels that can achieve amazing speeds. As a result of their unconventional design, typical calculations for hull speed (such as those used for monohulls) don’t always apply.

But what makes catamarans so much faster than equivalent monohulls? The first and most obvious speedy design element are the hulls themselves.

Catamarans don’t have a deep keel or a centerboard. This is because the second hull acts as a stabilizing device, and it helps the vessel track straight. The lack of a keel reduces weight (and equally important). It also reduces drag.

Additionally, catamarans behave in strange ways while underway. The hulls have a tendency to rise out of the water further the faster they go. This further reduces drag and makes it easier for the vessel’s speed to climb once it starts to move.

One additional characteristic is how the vessel’s sails point relative to the wind. Catamarans keep their sails perpendicular to the wind, which allows them to harness energy more efficiently. This is because, at a perpendicular angle, less wind energy is lost by spillage over the edge of the sails.

Are Catamarans Faster than Monohulls?

Yes, catamarans are typically faster than monohulls. They’re also a lot more stable, as their spaced-out hulls provide better motion comfort in rough seas. Catamaran hulls are narrower than monohulls, which also reduces drag and increases speed.

Catamaran vs. Monohull Speeds

We know that catamarans are faster than monohulls in most situations. But how much faster are they? Here’s a table of hull speeds for monohulls, which is a useful reference when comparing speed. Hull speed isn’t the absolute fastest that a boat can go, but it’s a good practical estimate for understanding the hydrodynamic limitations of single-hull designs.

Hull speed calculations for catamarans are more complicated. This is because catamarans have a greater length-to-beam ratio. And due to their narrow hulls and open center, they aren’t affected by the same hydrodynamic drag forces that monohulls are limited by.

For example, a 55-foot monohull sailboat with a waterline length has a hull speed of 9.4 knots or 10.9 mph. Its actual speed could exceed that in the right conditions, but rarely by more than a few knots.

Compare that to an efficient 51-foot catamaran, which can easily achieve speeds in excess of 20 knots in reasonable winds. That’s more than double the hull speed of a monohull with a similar waterline length and proves that catamarans operate under a completely different set of rules.

Wave Piercing

One aspect of catamaran design that makes them superior speeders is their ability to pierce waves. Specially designed catamarans have minimal buoyancy at the bow, which allows them to slice through waves instead of going over them.

This increases the speed at which catamarans can cover the distance. Think about it—a boat going over a wave has to use more energy to reach the same destination, as the height of the wave almost makes the distance further.

It’s like walking over a hill or on flat ground—you’ll take more steps walking up and down the hill than in a straight flat line. Wave piercing catamarans enjoy better stability, and they ‘take the flat road’ to a greater extent than monohulls.

Do Catamarans Plane?

Planing is when a boat’s hull rises out of the water due to hydrodynamic lift. This increases speed and efficiency, as there’s less drag but sufficient contact for stability. It also reduces rolling, as the bow only contacts the taller portions of the waves.

Catamarans have planing characteristics, but they generally don’t plane as dramatically as powerboats. This is still worth noting, as catamarans are specifically designed to use the phenomenon of hydrodynamic lift to gain speed and efficiency.

You’ll visibly notice a catamaran’s hull rising out of the water as it increases in speed. Compare that to a displacement monohull design (such as a classical cruising sailboat with a deep keel), which won’t rise out of the water in any significant way.

Are Catamarans Faster than Trimarans?

A trimaran is a catamaran with an additional hull in the center. Trimarans are usually less common than catamarans, but they have some of the same design benefits as other multi-hull sailboats.

At first glance, it would seem logical that trimarans are slower than catamarans. After all, they have an extra hull in the center, which likely increases weight and drag. However, there are more important factors at play here.

Trimarans are almost universally faster than catamarans. This has to do with weight distribution. Trimarans center their weight over the middle hull, using the outer hulls primarily for stability. This allows them to reap the benefits of a catamaran while increasing the efficiency of the wind power it captures.

Fastest Catamarans

Catamarans are popular for racing. There are several world records held by catamarans and numerous production boats with especially impressive speed-to-size ratios. Here are a few of the fastest racing and production catamarans ever built.

Fastest Sailboat Ever—Vestas Sailrocket 2

The Vestas Sailrocket is a specialized racing boat designed only for speed. This incredible vessel is actually the fastest sailboat ever built—and no wonder it’s a catamaran. A monohull simply can’t achieve record-breaking speeds when put head-to-head with a lightweight multi-hull.

The vessel, which earned the world sailboat speed record in 2012, has a modest 150 to 235 square feet of sail. Nonetheless, it managed to achieve a remarkable top speed of 65.45 knots in only 25 knots of wind. That’s about 72 miles per hour—in a sailboat.

Soon, a team of Swiss engineers will release their own version designed to beat the 65-knot speed record. Their vessel, which is a hydrofoil, will attempt to hit an incredible target speed of about 80 knots.

Outremer Catamarans

But what about production catamarans? How do they stack up, and how fast can they go? French boat builder Outremer Catamarans builds some of the fastest production catamarans ever built. These are not specialty racing boats—in fact, they’re average-sized cruising catamarans.

Let’s use the larger Outremer 51 as an example. This high-end cruising cat is known for its almost outrageous speed capabilities. In ideal conditions, owners of the Outremer 51 have reported speeds exceeding 20 knots for extended periods.

That’s a production catamaran with speeds that rival 20th-century warships. With such a fast boat, the world’s oceans start to appear a lot smaller. Plus, the genius design of the Outremer 51 allows it to be crewed by just two people.

But how do Outremer catamarans achieve such high speeds? The secret is in precise engineering and hull design, along with a sail plan that’s perfectly catered to the vessel. The hulls are sleek and narrow and designed to cut through the water with minimal drag.

From the bow, the Outremer 51 hulls look paper-thin. They increase in width gradually, which eliminates areas of sudden drag. These narrow hulls evenly distribute the vessel’s 21,825-lb displacement. Its low-buoyancy bows reduce drag and blast through waves instead of riding over them.

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Hull Speed Calculator for Marine Engineering

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Hull speed is a crucial concept in marine engineering, which refers to the theoretical maximum speed that a displacement hull can achieve efficiently. The concept is based on the length of the waterline, and the speed is calculated using a specific formula. This article discusses the Hull Speed calculation, its origin, applications, and significance in marine engineering and naval architecture.

Example Formula

The Hull Speed (V h ) of a boat can be calculated using the following formula:

• V h : Hull Speed in knots
• L wl : Length of the waterline in feet

Impact on Society

The Hull Speed concept has played a significant role in the design and construction of ships and boats. It has helped marine engineers and naval architects to design hulls that are more efficient and economical. Understanding hull speed is crucial for optimizing fuel consumption and achieving efficient voyage planning. Additionally, this concept is essential in various sports, such as sailing, where knowing the hull speed can help in maximizing performance.

Real Life Application in Industry

Hull speed is widely used in the marine industry, especially in shipbuilding. For example, in the design phase of a cargo ship, engineers need to calculate the hull speed to determine the most efficient hull shape and length. This calculation ensures that the ship can carry the maximum amount of cargo while using the least amount of fuel, thus maximizing profits. Furthermore, in sailing races, skippers use the concept of hull speed to estimate the maximum efficient speed they can achieve, which is critical for race strategies.

Key Individuals in the Discipline

William Froude (1810-1879) was an English engineer and naval architect who is known for his work in ship hydrodynamics. He introduced the concept of hull speed and the Froude number. His work on the resistance of ships and the efficiency of hulls remains a foundation in marine engineering and naval architecture.

Interesting Facts

• The concept of hull speed is fundamental in naval architecture and marine engineering, but it's also used in paddlesports like kayaking and canoeing to estimate the maximum efficient speed.
• Hull speed is sometimes referred to as the "displacement speed" because it is most relevant when the hull is moving through the water, displacing its volume.
• Advanced materials and hull designs have allowed modern ships and boats to exceed their theoretical hull speed without excessive power requirements.

Understanding hull speed is essential for marine engineers and naval architects. It is a fundamental concept that plays a significant role in ship design and construction. The hull speed is not just theoreticalbut has practical applications in optimizing fuel consumption, load-carrying capacity, and overall efficiency of a ship. Innovations in materials and hull designs continue to challenge and extend the traditional concepts of hull speed, but the foundational understanding remains pivotal for aspiring marine engineers and naval architects.

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Catamaran hulls- everything you need to know.

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• Published: July 17, 2022
• Updated: July 19, 2022

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Catamaran hulls are not like normal boats but provide increased stability. Let’s take a look at these incredible boats and how their hulls create one of the most versatile watercraft available today.

The Tamil Cholas used catamarans to ferry their troops to invade Malaysia, Indonesia, and Burma. The early paravars or fishing communities in the southern part of Tamil Nadu used two-hulled boats to fish. Polynesian seafarers were also early users of the catamaran, utilizing the watercraft to get to hard-to-reach islands. ( source )

Although the catamaran hull concept is a relatively new introduction to modern boat design , the boat has been in use since the 5th century. It was used for fishing, traveling, and transporting people and supplies. 

Parts Of A Catamaran

Here are the basic parts of the modern sailing catamaran:

• Hulls are what sets this boat apart from the rest. The catamaran has two hulls, while the monohull, as the name suggests, has only one hull. Most of the advantages of this boat are hinged on these two hulls. 
• The bridge deck connects the two catamaran hulls. 
• On top of the catamaran hulls and the bridge deck is the deck . It is where owners attach most of the equipment in a boat. 
• You can locate the berth, the galley, and other living amenities in the cabin . 
• The cockpit is where you find the navigation equipment of the boat . It is where you control the catamaran’s rudder, sails, and engine. 

Types Of Catamaran

The modern catamaran is far more different than its crude ancestor. Instead of tree cutouts, catamarans are now carbon fiber or fiberglass. Here are the different types of catamarans: 

Based On function

Pontoons are usually present on rivers and lakes and sometimes even on oceans, but they only travel near the shore.

In a catamaran pontoon-type boat, the pontoons serve as storage areas, where you will find the onboard motors. They are useful for water leisure activities such as short water trips, tubing, wakeboarding, and water skiing. 

Some pontoons may also serve as houseboats. They provide a broader, more stable platform ideal for a floating house. Plus, the space is bigger, and most of it is above water. It offers a better viewing option than a monohull. ( Source )

Small Waterplane Area Twin Hull is a catamaran-type boat that the United States Navy initially used for military purposes. They provide the water stability that is necessary when transporting heavy military equipment. 

One example of a military SWATH catamaran is the Spearhead class EPF. It is as long as a World War II escort destroyer, yet it is twice as fast at 43 knots. It can reach that speed because of its two separate hulls.

Because of their innate speed, SWATH catamarans can become patrol boats in lakes and rivers. They can easily outrun and outmaneuver standard watercraft.  

Nowadays, there are SWATH cruise ships and other non-military variations. ( Source )

Based On Design

• Sailing Catamaran

The smaller sailing catamarans do not have auxiliary engines, so the owner can propel the boat by harnessing the wind using the sails. It’s a popular choice for people with very little or no sailing experience because they are light and easy to use. 

The larger sailing catamarans are for group charters and long-distance cruising. They have become so popular lately that they now outnumber monohulls in tropical locations all over the world. They have a last, a headsail, and a mainsail. And the twin hulls have one engine each. 

• Power Catamaran

Unlike their sailing cousins, the powered catamarans do not have sails. They have massive engines which provide high speed. Their twin hulls are stronger and can carry and protect the large motors. 

The smaller “powercats” are used mainly for fishing. The bigger ones are rented out for charters and cruises. 

Catamaran Hulls Performance 

Thanks to the catamaran hulls, the boat offers many advantages over other boat types. 

• Because its dual-hull design provides a broader base, it offers more water stability than monohull boats. It makes the cat (catamaran) a popular choice for fishing expeditions and cruises.
• Riding a catamaran is ideal for people who feel seasick whenever they ride boats. The twin hulls prevent the boat from moving from side to side. The hulls allow the boat to travel smoothly, even on moderately choppy waters.
• The catamaran is the best choice when storing provisions and other household items with less heeling and bobbing. 
• The twin hulls’ stability is ideal for many activities such as cooking and partying. 
• Cats offer more moving space because of their broader base, thanks to dual hulls.
• With a catamaran, you have two great options on where to hang out. You can do it on the spacious deck or below the galley. 
• Compared to a monohull of the same size, the catamaran can accommodate more equipment and people.
• The living area in a catamaran is above the water line. This feature provides more natural light, a greater view of the outside, and better air circulation. 
• Since catamarans do not have keels, they can anchor on shallow waters, something that most monohulls will not be able to do. This ability of catamaran boats is impressive, especially if you are going around areas with many reefs and small islands.
• Catamaran hulls allow the boat to cut through the waves easier and faster. It means they require less engine power than their monohull counterparts.
• Because it has two engines and two rudders, the catamaran can easily maneuver in very tight spaces. 
• Because they do not carry heavy keels, catamarans can sail faster than monohulls. 
• The catamaran’s stability, speed, and weight make it a safer option than the monohull. It can sail in shallow waters, make a 360 degrees maneuver effortlessly, and carry more provisions. 

Disadvantages Of A Catamaran

Like any other boat type, the catamaran also has drawbacks and limitations. Here are some of them:

• The catamaran hulls prevent the boat from sailing as fast as the monohull upwind. The two hulls cause drag, and this slows the boat considerably. 
• Because of its bigger size, looking for a docking site can be more difficult and costlier than a monohull. 
• For hardcore sailing fans, the experience of sailing with a catamaran will never be able to match that of sailing with a monohull. To them, the challenge of true sailing is just not there with a catamaran.

What Are The Hulls Of The Catamaran Called?

According to the Online Etymology Dictionary, the Tamil word கட்டுமரம், which is pronounced as kattumaran, is where the word catamaran takes its name. The word means “pieces of logs tied together”. Through the years, the term has evolved into what is now a catamaran in English. 

What Are The Characteristics Of A Catamaran Hull?

• Both hulls of a catamaran complement each other to achieve very minimum water resistance. 
• Because of this, it takes less energy to propel a catamaran, whether via an engine or sails. 
• The catamaran hulls provide stability to the boat. The twin-hull significantly reduces bobbing. 
• The catamaran’s ability to keep steady on the water makes it an ideal vessel for cooking, dining, and storing provisions. 

Are Catamarans Good In Rough Water?

Catamarans are amazingly stable in rough water. The catamaran’s design and build, which provides stability, are factors why it is one of the best boats to use when the waters are choppy. 

Yes, catamarans are relatively more expensive than monohulls. Nevertheless, since single-hull boats are less expensive, their resale value is also cheap. 

If you add all the advantages that a catamaran offers – safety, comfort, and speed- it does not come out expensive. 

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• PERFORMANCE TOPICS

Optimising Hull Lines for Performance

This article was inspired by a question about the rocker line in the new 8.5m cat Design 256 and I want to stick to the point, so we won’t turn it into a book, but I’ll discuss two issues, hull fineness ratio and some aspects of the rocker profile.

When you manipulate the hull form you’re adjusting the lines in three planes, waterplanes (plan view), buttocks (side view including the keel rocker) and the section shapes. So you need to be aware of how the shapes are changing in the other two planes as you manipulate any one of these three, or all three globally as is now possible with computer modelling.

There are two fundamental constants that you start with and don’t change throughout the process. The big one is the displacement or the amount of buoyancy you need.

If you make the hull finer by narrowing the waterlines you have to increase the draft or make the ends fuller to get back to the required displacement number.

If you flatten the rocker line you have to increase the hull width, fill out the ends, or square up the section shapes rather than having a V or rounded V. 

The other constant is the longitudinal centre of buoyancy. You really can’t do any meaningful shaping of the hull form until you have settled on the these two constants.

A third number that we can plug in as a constant if we want to is the prismatic coefficient which describes bow much volume there is end the ends relative to the cross section shape in the middle of the boat, but in sailing boats this is of less importance compared to other factors. 

The hull lines for Design 256, 8.5m Cat. It's that hump in the rocker line - right under the back of the cabin that brought up the question and is one of the key points discussed here.

Hull fineness.

Fine hulls are fast, but only in the higher speed range. There’s a misconception I come across quite a bit that you can add weight and windage and you’ll still be fast as long as your hulls are fine.

Well you won’t be. Your boat will simply sink to find the new state of equilibrium. If your transoms are submerged you’ll have more drag. If your bridge deck is too close to the water you’ll have slamming. Much better to be conservative with your displacement figure in the design stage than overly optimistic.

And fine hulls have more wetted area so you have more drag in light air where friction resistance is the primary drag factor. 

I’ve seen promotional material for catamarans stating that the boat has less wetted area because it has fine hulls. For a given displacement the minimum wetted area is described by a sphere (or a semi sphere in the case of a floating object). The more you stretch it out in length, keeping the displacement constant, the more wetted area you have.

The more you make the section shape into a deep V or a broad U with tight corners, as opposed to a semicircle, the more wetted area you have. Add into the equation finer hulls are slower to tack.

So fine hulls are only an advantage if your boat is light and has enough sail area to ensure you’re travelling at speeds where form resistance is greater than skin resistance.

In my view the advantage of fine hulls is often overrated as it applies to cruising cats.

At the other end of the scale the resistance curve is fairly flat up to about 1:9 which is still quite fast in most conditions. From there the resistance rises steeply as the hull gets fatter and at 1:8 and fatter you’re suffering from some serious form drag.

This is the rocker line isolated from the lines plan above (in blue) and and the red line shows a more moderate rocker line that achieves the same buoyancy and maintains the centre of buoyancy in the same position.  The bow is to the right.

In the image lower right I've squashed it up and increased the height to make the difference in the lines more obvious.

The difference in the two lines is quite subtle, but races are often won or lost by seconds.

Rocker Profile

So if we’re looking for low wetted area we would want a rocker profile that was even and rounded, relatively deep in the middle and rising smoothly to the surface at each end. But this would give us a low prismatic which is not ideal in the higher speed range, and it’s not ideal for pitch damping which in my view is the critical design factor that is often underrated. 

Pitching is slow. It destroys the airflow in your sails and the flow around the hulls, and your performance is suffering from slamming loads.

The single most effective way to counter pitching is with asymmetry in the water planes. You can achieve that in the with a fine bow and broad transom. Or you can achieve it with V sections forward and a flattened U shape aft. Or you can achieve it in the profile view with a very straight run forward and a bump in the aft sections. A flatter rocker line is better for resisting pitching than an evenly curved one with deeper draft in the middle.

The final result is a combination of all three of these factors.

On a cat like Design 256 the weight is concentrated well aft so we need to get buoyancy well aft.

The kink you see in the rocker profile helps to do this. It also helps to keep the rocker straight for most of its length and smooth the water flow exiting the hull aft at higher speeds, possibly promoting some planing effect.

If we had a more even rocker line we would slightly reduce the wetted area, but we would increase the pitching and the water would exit the hull aft at a steeper angle, increasing form drag in the higher speed range.

How much of a bump can you put in there without creating a flow separation, and how damaging would that flow separation be? I really don’t know. The way all of these factors interplay in the various conditions we sail in is very complex.

Ultimately a lot of this work is gut feel nurtured by experience, observing things in nature and most importantly experimenting and trying new ideas.

Is the new Groupama AC45 a breakthrough that will influence the form of racing catamarans into the future? I don’t think anyone has a computer that can answer that. We have to wait and see.

Symmetric and non symmetric water-planes. The blue line with grey fill is the DWL from the design above. As is typical with modern cat hulls the bow is long and fine, the stern is full and rounded. This is the asymmetry that has a damping effect on pitching. The red line on the other hand is more like you would see on a double ended monohull and quite a few multihulls have also used this shape in the past. It's quite symmetric about the pitch axis and does not have good pitch resistance.

The hull lines of the new 8.5m Sports Cat Design 256

Mad Max , Previously Carbon Copy . She was designed in 1997 but she's the current (2016) title holder of the Australian Multihull Chamionships (2 successive years) and the fastest inshore racing boat in Australian waters.

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How Fast Do Catamarans Sail? Average Sailing Speed of a Catamaran

In most aspects, sailing a catamaran is very similar to sailing a monohull. If you learn to sail on a monohull then most of the skills are transferable. But, there are a couple of subtle differences that we will analyze further in this article. A catamaran is generally more balanced on the water and can be faster than a multi-hull vessel. And, cruising on a sailboat with a cat hull will be much faster than cruising on a sailboat with a monohull. Therefore, a catamaran hull is able to achieve the speeds of a racing monohull and is also more comfortable to sail on.

A tri-hull is even much better as they’re designed towards the performance end of the spectrum. And that is why they double the speed of a racing monohull. So, let’s analyze this subject further in this article and see what’s the average sailing speed of a cat. Follow me!

Catamaran Vs Monohull Speed: Are Cats Faster than Monohulls?

Not all cruising cats are always faster than an equivalent length monohull. But, many well-designed and balanced multihulls can easily surpass the speed of their monohull cousins. And, it’s not fair to mass all cats into one example, but performance cruising catamarans like the Nautitech or Neel trimarans distinguish from others. Their narrow waterline beams, hull chines, deep and fine keels, and rudders as well as efficient sail plans will typically be faster than the average cruising monohull.

“The fun of sailing is proportional to the speed of sailing”, as an American designer, L. Francis Herreshoff, said. And, it’s basically true because when we sail and see another boat heeling in the breeze, we also feel we want to do the same. This is because for many sailors speed means much more than just fun. You should, however, consider keeping your cat as light as possible if you want to maximize speed. I know that keeping your sailboat light is difficult but it’s of importance if speed is your main goal.

Keep in mind that a boat’s speed has won wars and has also been a contributor to safety. In the past, a fast warship was able to outmaneuver its adversary or escape from a boat with more firepower. And just as proven in history, the speed of a sailboat is important and provides a faster boat with more options.

Monohull VS Catamarans Differences

• When tacking, you must work hard to keep your speed consistent in the tack and always ease the mainsheet to avoid “windvaning.” When the larger mainsail on a catamaran attempts to turn the boat back towards the wind, this is known as windvaning.
• On a monohull, you must be extremely cautious about an unintended gybe. Meaning that you must gybe much more slowly. On a catamaran, you can take advantage of the increased speed and sustain it while gybing to help depower the main.
• On a monohull, and when winds increase, the boat starts heeling. This automatically informs you that you have too much sail up and it’s time to reef. And, as catamarans don’t heel, you have to be very careful when to reef the massive main. Most of the time, you will throw in the first reef at 18-20 knots of wind speed. The second reef will be put as the wind gets closer to 23-25 knots. The above-mentioned always depend on the size and type of your vessel.

Wind as a Main Factor for Speed

Thanks to tech evolutions in radar, satellite, and computer technology, a five-day forecast is as accurate as a two-day forecast was back in 1980. A multihull’s higher speed also contributes to easier and safer planning of ocean passages around weather windows since exposure time will be less. Moreover, meteorological prediction for shorter periods is far more accurate. Keep in mind that when sailing faster you also introduce the concept of apparent wind to the strategy of efficient sailing.

Multihull speed upwind? Sailing upwind, the catamaran usually experiences more apparent wind across the deck since it’s sailing faster. Therefore, the sails will feel more pressure, which will make the boat perform even better. And, of course, the concept of apparent wind contributes to the joy of sailing, as it adds another dimension to it. When sailing towards a downwind destination, fast multihulls are able to sail at smaller wind angles. Subsequently, this brings the apparent wind forward of the beam, hence optimizing the angle of attack on the sails.

While cats will fly gennakers, code-zeros, or asymmetric spinnakers, monohulls mostly set symmetric spinnakers to the poles. And most importantly, their boat speed will often cancel out the true wind and will reduce the apparent wind and performance. The faster the multihull is the more it is able to take advantage of the apparent wind and tack downwind towards its destination. Although it might be sailing twice the distance, it will arrive at the downwind mark quicker because its Velocity Made Good (VMG) will be faster.

>>Also Read: How Fast is a Laser Sailboat? Laser Sailboat Top Speed

Performance Characteristics

Bear in mind that cats require four times the power to double their speed. But, a mono-hull vessel requires eight times the power to double the speed. This is due to the fact that a cat has less resistance in the water. However, this is great in terms of conserving and using less energy. Catamarans are also more stable in the water. This stability is effective at resisting heeling or capsizing. In other words, a multi-hull vessel requires four times the force to capsize as a similar-sized mono-hull vessel.

Most of the time, sailing in a catamaran is smoother and facilitates activities that are not always possible on a mono-hull sailboat. In addition, as catamarans have less water resistance, they are generally faster than mono-hull vessels. As their hulls are smaller, this means that they have a smaller bow wave to fight. The bow wave is a wave created by the displacement of water by the bow of a ship. After a certain speed, the boat has to start hauling itself over its own bow wave. Meaning that the larger hull a boat has, the larger its bow wave will be and the more power will be required in order to fight it.

Since catamarans have two small and narrow hulls, they don’t have much of a bow wave. This is one of the reasons they are normally quicker than a monohull vessel of comparable size. Catamarans can travel at speeds of up to 30% faster than monohull boats. Catamarans have the disadvantage of taking longer to transform than monohulls.

Lastly, the thing that makes monohulls harder to sail is heeling and smaller spaces. In stronger winds, monohulls tend to heel. This results in making most tasks a bit more difficult to perform. Whether you’re heading forward to reef, trying to winch in a sail, or move about the boat, sailing on a heeling boat is always more difficult. However, cats have extra stability and room, and this allows for much easier movement around the boat as they do not heel. And, for this reason, catamarans are often considered easier to sail.

How Fast Are Catamarans Compared To Other Boat Types?

There are two main factors that determine the speed of ships. The first one is the hull type. There are hulls that stay beneath the water more or less than others. But, keep in mind that the less the hull is underwater, the faster it can go. This is due to the fact that the less of the hull underwater, the less the drag created when sailing. The other factor is the length of the boat. And, reasonably, the longer the boat, the faster it can go. Every boat has a maximum hull speed that can’t be exceeded. This can only happen in case the boat can plane on the water’s surface or be lifted on hydrofoils. For most boats, the longer the boat, the higher the maximum hull speed is.

Sailing catamarans typically average about 10 knots while pontoon boats average about 16 knots. As for powerboats, they can average anywhere between 30 and 50 mph. Most average sailboats are designed with monohulls and they average from 6 to 9 knots depending on wind conditions. Generally, sailboats average between 8 and 12 mph, again depending on weather conditions. This includes mono-hull between 6 to 8 mph and cats or trimarans between 9 and 10mph.

Speed and Comfort Considerations For Cats

You have a lot of choices if you choose to buy a catamaran. You have the option of prioritizing speed or comfort. After you’ve decided to buy a catamaran, the type of catamaran you can consider is determined by where you’ll be using it and what you’ll be doing with it. In addition, make sure that you look at what type of water you will be traveling in, your crew members, and what type of speed you want to achieve.

Storage is an important consideration to make before purchasing a catamaran. Due to the beam, or width, of a catamaran versus a regular mono-hull vessel, you are often charged for two slips if you wish to store your boat in a marina. Moreover, catamarans are a great option for those who get seasick because they have a more stable ride and more open air space. You have more windows and visibility since the living quarters are not within the hull and below the water’s surface.

Sailing and power catamarans are both great choices. In addition, for low winds or conditions such as docking in a marina, sailing catamarans may be equipped with backup power engines. Twin-engine catamarans can have more power and precision than mono-hull vessels.

>>Also Read: How Fast Can Sailboats Go?

Main Advantages of Catamarans

• Space! If you want to opt for more interior and exterior space then the two separate hulls of a catamaran can often double the amount of social space than a monohull of the same length.
• Catamarans are far more stable than monohulls. For this reason, they don’t heel when sailing, and are less prone to rocking when at anchor. This factor also contributes to comfortable sailing.
• Catamarans have a shallow draft which allows them to enter shallower areas. Keep in mind that in the South Pacific, most lagoons are 6 to 8 ft in depth. This depth doesn’t allow for monohulls to enter, but a catamaran can easily enter these areas.
• Stability is another big plus of cats. A cat isn’t that susceptible to the effects of wave action and it also doesn’t heal the way a monohull does. Therefore, it’s much easier to walk around on deck and within the interior of the cat while underway.
• In terms of speed, and mostly for downwind sailing , cats are faster than monohulls. This particularly applies to downwind runs, reaches, and broad reaches.
• More light, customizable, and airy living area. On a catamaran, the living space is usually situated in the middle of the boat and built on the bridge deck. But, in a monohull you go down into the hull where it is darker and less airy.
• More storage space and room for extra systems, provisions, and general sailing equipment. These may include air conditioning, heaters, oven, watermakers, generators, larger fridges, and freezers, etc. And, if you’re a liveaboard, then living on a cat is far more comfortable than living in a sailboat. You have more interior, exterior, and storage space as well as stability and speed in terms of sailing performance.
• Many modern cats have flybridge helms. And of course, no monohull achieves this visibility from the helm provided on most modern catamarans.
• The galley, main salon, and cockpit are all located on one level , above the waterline.
• Because the majority of living space is above the waterline , there’s a better flow of ventilation on a cat making the need for air conditioning somewhat less important during the daylight hours.
• When you plan to set sail, you almost never have to rush around stowing stuff or using bungee cords to hold things in place. Except in relatively rough waters, most things stay put.
• Since catamarans lack a large, heavy keel filled with lead, they can float even if they’re holed. Production cats are constructed with so much buoyancy that sinking them is nearly impossible.
• Catamarans are usually easy to dock because you have two motors and two rudders. Additionally, there’s also no need for a bow thruster.
• Most catamarans are able to turn 360 degrees within their own length.

Average Sailing Speed of Catamarans

How fast do catamarans sail – the bottom line.

Bear in mind that not all catamarans are created equal. In other words, catamaran speed is relative. The most important benefit of the speed of a multihull is the ability to outrun bad weather. Meaning that you’re able to average 9-10 knots on a catamaran rather than 6-7 knots on a monohull. Subsequently, this will give you more options in your strategy to avoid bad weather. In general, sailing catamarans typically average about 10 knots. Higher maximum and average speeds are what makes cats distinguish as well as their stability. These are the most important characteristics which makes many sailors prefer cats rather than monohull boats.

Peter is the editor of Better Sailing. He has sailed for countless hours and has maintained his own boats and sailboats for years. After years of trial and error, he decided to start this website to share the knowledge.

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Catamaran Design Guide

Spectacular sunsets in the Pacific turn the horizon into a brilliant spectrum of gold and orange colors.

Copyright © 2006, 2008 by Gregor Tarjan. Click here for terms of use.

performance, yet desire high daily averages and passage times, which should be as short as possible. When choosing a large multihull, sailors look, above all else, for safety and comfort, long before the consideration for flat-out speed comes into the discussion. Nevertheless, performance is a highly important design consideration. No catamaran sailor wants to sail slower than a same length ballasted keelboat. Below are some EVALUATION & COEFFICIENTS useful coefficients, which will help compare monohulls and multihulls objectively.

Bruce Number (BN)

below "Indigo," a magnificent Wormwood 70, sailing in sparkling Caribbean waters.

Various multihull characteristics and design features can be expressed in mathematical formulas. Their results are crucial and will give prospective owners a basis of comparison between different types of catamarans. These numbers are important, as they eliminate ambiguity and clearly display various advantages or concessions of a design, which would be hard to quantify any other way. Mathematical coefficients not only will provide insight into a boat's performance in varying conditions, they also reflect concerns about loads to be carried safely, speed and stability.

We have already mentioned the Displacement/Length and Sail Area/ Displacement ratio in our chapter on Multihull Advantages, illustrating the point of a multihull's efficiency. Let's look at some other coefficients that give us an indication of a boat's performance.

What is performance and how do we really measure it? Most people who buy a cruising catamaran are not really interested in racing

The Bruce Number is very similar to the Sail Area to Displacement ratio although the formula is slightly different. It is the square root of the sail area in feet, divided by the cube root of the boat's displacement in pounds:

SA = upwind sail area (mainsail and 100% jib)

Displ = weight of the boat in pounds

Similar to the Sail Area to Displacement ratio, the higher the coefficient the faster the boat and better is its performance in light air. Typically a BN of 1.1 will be the threshold between fast and more sluggish multihulls. A heavy displacement monohull might have a BN of .7, whereas a modern cruising catamaran shows a BN of 1.3. Offshore multihull racers can have BNs of 2.0 and higher. The BN will also tell us about a catamaran's ability to withstand stronger winds before reefing. A boat with a higher BN is usually overcanvassed in strong conditions and will have to be reefed earlier than one with a lower coefficient.

On the other hand, they will be able to produce more "power" than their counterparts in lighter winds and perform better.

Sail Area to Wetted Surface (SAWS)

SA/WS = Sail Area Wetted Surface Coefficient

SA = upwind sail area

WS = total underwater surface area (hull and appendages)

This formula simply divides the upwind sail area of the boat (mainsail and 100% jib) by the wetted surface. This coefficient will give us a statistical indication of the multihull's lightair performance since in low wind conditions skin friction becomes an important factor. Monohulls can have coefficients of at least 7% more than multihulls.

Hull Fineness Ratio (HFR)

The Hull Fineness Ratio, known as the hull's beam-to-length ratio, is an interesting number. It is derived by simply dividing the waterline length of the hull by the waterline beam of the hull.

Max. WL/Max. Beam WL = Hull Fineness Ratio Max. WL = length of the hull at waterline in ft. Max. Beam WL = beam of the hull at the waterline in feet.

Monohulls, when compared to multihulls, have low hull/fineness ratios. In Part 1 of this

book, discussing "Efficiency," we saw that ballasted keelboats are limited to Archimedes' principle of hull speed (1.34 x VWL). Multihulls do not have these theoretical barriers, because their hulls are narrower.

The thinner the hull the faster it will be able to travel through the water. But, attention! It will also carry less unless you are on a mega cat. Typically, a 40' cruising catamaran's HFR will range from 8:1 to 10:1. Dennis Conner's above While sailing under spinnaker and experiencing virtually no roll at all, guests will always find a comfortable spot to relax on the foredeck, an impossibility on a monohull.

There are various methods of calculating the transverse stability of a catamaran. One of the simplest and most utilized techniques is establishing a relationship between the height of the Center of Effort (CE), displacement, beam and sail area. Multihull designer, James Wharram added safety factors of 20% to compensate for gusts and the dynamic environment of the ocean. Another method is described in the text below.

Multihull Stability & Capsizing Moment d - Displacement (kg) x half beam (m) max ~ Sail Area (sq m) x Height of Center of Effort (m)

P max = maximum pressure exerted onto sails

Multihull Stability & Capsizing Moment

height of sailplan CE

half overall beam (half hull beam)

racing cat "Stars and Stripes" had a 16:1 HFR. Of course, the larger the boat, the narrower the hulls will become in comparison to its length. For example, the HFR of a 100' luxury catamaran may be 12:1, providing it with a high speed potential. However, monohulls can show HFRs of 3:1, though the comparison is complicated as their angle of heel affects the measurement.

One has to be very careful when analyzing the Hull Fineness Ratio of a cruising catamaran, because other factors such as the actual shape of the hull cross sections (Prismatic Coefficient, PC) can throw the analysis off balance. Go-fast sailors like to think that fine hulls are always fast. That is not necessarily true because a slim hull could have a large underwater volume, thus slowing it down. Consequently, a wide waterline-beam hull could have less drag than a narrower one. It could have a shallow underbody (low PC), which would be beneficial to load carrying (Pounds Per Inch Immersion Number, PPI) and early surfing characteristics at speed.

Stability Coefficient (SC)

This mathematical formula has been devised by the distinguished catamaran designer and sailor James Wharram and his team. This coefficient analyzes a multihull's ability (in a static environment) to resist capsizing due to wind.

( 0.682 VW x (.5 Boa) ) x .555 = CW .00178 x SA x h

W = Wind speed, apparent, in mph CW = Critical Wind Speed to capsize in mph SA = upwind sail area in sq ft. h = height of Center of Effort (CE) of total sail area

Boa = Beam overall

This formula will tell us how much wind it will take to overturn our multihull. By instinct we will know that a catamaran with a wide stance and a conservative sail plan will be very stable offshore. The SC formula will inevitably illustrate that a wider beamed catamaran with a tall sail plan will be as resistant to wind induced capsize as a short-rigged, narrower boat. This is not so if one considers the chaotic environment of waves and the real world of heavy weather sailing. It is interesting to note that a wide beamed boat (regardless of the SC) is more resistant to capsize in seas due to the effects of a higher moment of inertia. In an open-ocean environment, which is everything but static, the SC formula has little meaning. Nevertheless, it serves as a good basis to evaluate stability as a factor of wind force.

below When the wind suddenly comes up, all that is needed is a couple of turns on the jib furler to quickly reduce the headsail size. The catamaran will hardly sail any slower, but feel more comfortable.

Wide hulls and a large overall beam will increase the overall righting moment of a catamaran. A word of caution: Excessive beam will reduce the fore and aft stability. Designers strive to compromise hull fineness ratios, place heavy weights towards the CG (Center of Gravity), and engineer hull and overall beam to achieve a seaworthy balance, which is safe, yet provides ample liveaboard accommodations.

Catamaran Stability Considerations

Diagonal Stability & Beam-to-Length Ratio (BLR)

Stability of a multihull, or the resistance to capsize, should be seen as three components. Athwartship Stability is one well-publicized type and the one often talked about. The other much more important types are Fore and Aft and Diagonal Stability. Fore and aft stability is established by the relationship between the boat's waterline length and the distance between the hull centerlines. It will reflect the catamaran's resistance to tripping. This relationship should be in the vicinity of 39% to 42%. For a seaworthy cruising multihull it is important maintain the proper ratio between length and beam, which, in turn, balances equal amounts of athwartship with diagonal stability. The goal should be to prevent the possibility of a sudden discrepancy of powers between fore and aft and sideways resistance. Most of today's multihulls keep these two component forces in equilibrium, making them extremely seakindly and safe.

Some early design multihulls were very narrow, partly due to the material limitations of that time. But things have changed. Contemporary composite construction allows designers to build wider boats without compromising stiffness. Production catamarans of today have a wide stance and have the benefit of greater safety margins in gusty wind conditions than their older cousins. Multihulls are sophisticated structures and true modern miracles. They provide a more comfortable ride and more interior room. Thanks to modern materials they weigh less and perform better than catamarans built only 10 years ago.

Some catamarans, especially production boats, which are very popular in the charter fleets, are growing wider by the year. The businesses who rent these beamy monsters adore them. Lots of room plus open decks are ideal for clients and the bigger (wider) the boat, the more paying guests can share the fees. But there certainly is a limit as to how wide is too wide. Extreme beam can be dangerous. It can lead to instability fore and aft and to excessive bridgedeck slamming, as the relative distance from the bridge deck to the water will decrease with an increase in width. A vessel with excessive beam might seem stable athwartships, but it will compromise overall stability.

We know that multihulls can, in extreme cases of seamanship error in wild storms, be thrown over from any side - front, back and beam-on. The best examples of this phenomenon are racing multihulls, especially Formula 1 trimarans, which have fine hulls for speed and huge sailplans to provide driving power. They are initially extremely stable athwartships (High Beam-to-Length Ratio), but have a tendency to become unstable fore and aft. They will surf down waves and reach a point where the power of the sails, and speed, will exceed the ability to keep the bows out of the water and the boat will pitchpole. This is the reason why catamaran designers usually draw their multihulls with a Beam-to-Length relationship of between 50% and 55%. The longer the vessel the lower that percentage becomes.

I am currently involved in the "Gemini" project, which presents an example. It very well might become the world's largest sailing catamaran. She will have an overall length of 145 feet, yet her beam will "only" be 54.4'.

Please, don't worry. "Gemini" will not be tender and tip over in the slightest breeze. On the contrary, this monster will be one of the most stable craft afloat, although the beam-to-length relationship is only 37%. The relatively low beam-to-length ratio also involves the fact that the boat would be too heavy and building costs would be prohibitive if she were to have a standard 52% BL relationship. Most importantly, could you imagine turning a 75-foot-wide boat?

above Asymmetric spinnakers on furlers are great inventions. They add instant sail area, yet can be doused in a matter of seconds when the wind picks up strength.

above Although this Edel 35 was a good-looking and popular catamaran, it suffered from excessive bridgedeck pounding, which was caused by only several inches of clearance between the saloon's underwing and the sea.

Obviously there is a sweet spot in the beam vs. stability question. Designing too beamy a boat will also necessitate more freeboard to preserve bridgedeck clearance which, in turn, will increase windage and complicate maneuvering. Unless sophisticated aramid construction methods are utilized, more beam will also add more weight and stress to the structure. Adding more mass will, to a certain point, help make the boat more stable, but where do we stop? Is it better to add weight or width to make a boat stiffer? Of course, both characteristics are interrelated as a beamier boat normally is also heavier. Just adding weight to a catamaran simply to make her more stable will not pay off. Consequently, making a boat too wide might increase living space yet it will also burden the structure, require a beefier manufacture, and yield an even heavier boat. Needless to say, a boat which is too wide will also create practical restrictions such as maneuvering, the ability to haul the vessel and much higher building costs.

Beam has a great effect on bridgedeck clearance, which is one of the most vital characteristics of a good cruising catamaran. As standard practice, the well-known rule of 1" of bridgedeck clearance for each foot of beam was a safe way to prevent excessive wave slap. The wider the beam the more the relationship changes and the necessary height of 1" per foot of beam needs to be increased to 1.3" or more. In the extreme case of overly square boats, that number will have to be closer to 1.8" per foot of beam. This will have a negative effect on any seaworthy multihull that has a bridgedeck saloon. The wide beam will necessitate a high cabin sole to remain a safe distance from the waterline. In order to provide standing headroom, the coachroof might be higher than practical, which could result in a boxy, high-windage multihull. Not only will this be unattractive, but also raise the Center of Gravity (CG) which really should be kept as low as possible.

More overall beam on the other hand (given that there is still sufficient bridgedeck height) has a less known benefit, as it reduces the possibility of hull-wave interference, which is particularly important for fast designs. The wave interaction between the hulls can lead to additional resistance, and especially in an agitated sea state, the formation of wave crests can pound the bridge deck. Most early narrow-beamed catamarans suffered from this phenomenon,

Ultimately, a boat's design has a major influence on its ability to stand against the forces of nature, and to keep occupants safe. Manufacturing excessively wide catamarans is like trying to market monohulls with super deep-draft keels. Both are totally impractical. We designers have to make sensible compromises and learn from past experiences of what has worked at sea by balancing the benefits of a wide boat with its disadvantages.

below This narrow-hulled Outremer 64 Light has completed her third circumnavigation with the same owners. Note the smooth underwing clearance, lacking any protrusions or steps.

"A great cape, for us, can't be expressed in latitude and longitude alone. A great cape has a soul, with very soft, very violent shadows and colors. A soul as smooth as a child's, and as hard as a criminal's. And that is why we go!"

~ Bernard Moitessier

Dinghies, windsurfers and every imaginable type of water toy can be stored conveniently on large catamarans and easily launched from the wide transom steps for shore-side pleasures. Note the twin life rafts located in special compartments on the massive aft crossbeam.

Continue reading here: Hull

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• Hull Construction - Ship Design
• Geometry - Ship Design
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Readers' Questions

What length should a stub keel be to waterline length on a catamaran?

There is no set rule for the length of a stub keel on a catamaran in relation to its waterline length. The length of the stub keel will depend on various factors, such as the size and design of the catamaran, intended use, and specific requirements of the boat builder. Generally, the stub keel on a catamaran is designed to provide stability and improve sailing performance, so it is important to consult with a naval architect or boat designer to determine the appropriate length for a specific catamaran.

What is a 16 passenger catarmarn like?

A 16-passenger catamaran is a type of boat or vessel specifically designed to carry 16 people comfortably. Catamarans are multihull boats with two parallel hulls, which are connected by a deck or a structure. They offer stability, speed, and efficiency in the water. A 16-passenger catamaran can vary in size and design, but generally, it will have enough seating or lounge areas for all passengers. It may have indoor cabins with beds or seating areas, as well as outdoor spaces for relaxation or socializing. These boats often come equipped with amenities such as bathrooms, kitchens or galleys for meals, and sometimes even entertainment systems. The catamaran's size can influence its specific features. Some catamarans are designed for day trips or shorter excursions, while others are built for longer journeys or overnight accommodations. Additionally, they can be used for various purposes, such as whale watching, diving trips, ferry services, or private charters. Overall, a 16-passenger catamaran provides a comfortable and stable platform for small groups or gatherings, allowing passengers to enjoy the beauty of the water while ensuring safety and comfort.

Is the catamaran hull floor always on the waterline?

No, the hull floor of a catamaran is not always on the waterline. The design of a catamaran allows for the hulls to be elevated above the waterline, reducing drag and increasing speed. The position of the hulls in relation to the waterline can vary depending on factors such as the weight distribution, load, and sailing conditions.

How close to a catamarans design reefing points should you go?

You should always be careful when approaching reefing points on a catamaran and stay as far away as possible. Generally, you should aim to stay at least 10 meters away.

What keel to length ratio for catamarans?

The keel-to-length ratio for catamarans typically ranges from 0.1 to 0.25.

Is 70% length to beam ok for a catAMARAN?

Yes, it is generally accepted that a catamaran should have a length to beam ratio of between approximately 6:1 and 8:1. Therefore, a 70% length to beam ratio would be within an acceptable range.

What is the waterline length to baem ratio of a typical cruising catamarans?

This ratio will vary depending on the type and size of the catamaran. Generally, the ratio should be between 1:1.5 and 1:2.5, with 1:2 being the most common.

My Cruiser Life Magazine

Sailing Catamaran Speed

You’ve probably heard that one of the best reasons to get a catamaran is because they’re fast. After all, there’s a race any time there are two sailboats on the same waterway.

But like all things in boating, speed is a relative term. Catamarans seem fast to those coming from slow and heavy monohull sailboats, but cruising catamarans are still pretty slow vessels. There are indeed high-tech racing catamarans breaking speed records all the time. Still, the vessels that most liveaboard cruisers venture out on are only slightly faster than their monohull counterparts. 

For this article, we will look at the types of catamarans people live on and cruise on. Forget about those fantastic America’s Cup yachts or those multihull go-fast fishing boats for a few minutes. 

I have had experience cruising and living aboard both catamarans and monohulls. For five years, my wife and I enjoyed catamaran sailing on a Lagoon 380. We then switched—for many reasons—to a Cabo Rico 38. The Cabo Rico is a traditionally-designed monohull with a full keel and a heavy displacement. In other words, it’s about as far away from a “speedy” catamaran as one can get.

Table of Contents

How fast can a catamaran go, measuring catamaran speed, catamaran speeds vs monohull speeds, sailing cruising catamarans, performance cruising catamarans, racing catamarans, power cruising catamarans, catamaran top speed, faqs – how fast are catamarans.

There’s no doubt that catamarans are some of the fastest sailboats around—but there’s also a lot of misinformation and misunderstanding online about how fast they really are. 

Realize that not all catamarans are created equally. There are cruising catamarans built to carry their passengers in comfort. And then there are racing catamarans built for nothing but speed. Somewhere in between, there is a poorly-defined category of “performance cruising” catamarans that stir passions.

So, are catamarans fast? Well, it’s all relative. But, if you compare them to monohull sailboats of similar sizes and capabilities, the catamarans are usually faster for several reasons. 

The speed difference is even harder to measure in the cruising catamaran category. One of the reasons catamarans beat monohulls during races is because they are built light with no ballast. But a heavily-laden cruising cat ready for an ocean crossing is hardly “lightly loaded.” Will it still beat a similarly heavily-laden monohull? Sure! But probably not by as much as you might think.

Boats measure their speed in knots. Traditionally, this was measured by a tool known as a knot log. The modern equivalent is an underwater instrument with a spinning wheel that effectively measures the speed of the water passing over the hull. So long as no currents are present, that speed will equal the boat’s speed over the ground (SOG).

Satellite navigation allows us to measure our SOG more accurately, but this isn’t a great indication of boat performance since it will be affected by tides and ocean currents. 

For landlubbers, one knot is equal to about 1.15 statute miles. So, in other words, when we say that a sailboat cruises at 6 knots, it means it’s going about 7 mph.

But before going any further, consider this—the maximum speed that a sailboat makes is generally a pretty meaningless number. Maybe the knot log pegs to 13 knots for a few seconds, thanks to a strong gust of wind while you’re headed down a large swell. Does this mean you’re driving a 13-knot boat?

A voyaging sailor who has made a long passage will have little interest in this sort of number. When you’re crossing oceans, what really matters is how many miles pass under the keel each day. The more miles you tick off, the shorter the passage. So most sailors learn quickly to look past the “fastest speed in knots” number and find real-world stats on passage miles. 

Comparing speeds between radically different sailing vessel hulls is like comparing apples to oranges. Even seemingly similar boats, like “cruising sailboats,” the differences between one and the other are endless.

For example, let’s say you wanted to compare 38-foot monohulls to 38-foot catamarans. The speed of a monohull is limited by waterline length, which means you’d have to look at a hull that is significantly more than 38 feet in most cases. On the other hand, the catamaran is known for long swim platforms on inverse transoms and plumb bows—meaning most 38 foot cats have nearly 38 feet of waterline. 

Then, what sort of hull design makes a fair comparison to a catamaran? Would it make sense to compare a transitional, salty 38-footer with a full keel? Probably not. Most sailors interested in the cruising catamaran lifestyle would more than likely be comparing it to a modern monohull with a flatter bottom, fin keel, and spade rudder. 

What about the catamaran? There’s a lot of variation in the catamaran field regarding performance. If speed is your goal, you likely want to compare the high-end performance brands—Outremer, Gunboat, HH, and the like. These boats are becoming more popular, but most cruising cats you see on the water are not performance models. Instead, they are the big and comfortable cruisers made by Lagoon, Leopard, or Fountaine Pajot.

Finally, how can you fairly compare the stats? Boats sail differently in different wind speeds and at different points of sail. In other words—there are a lot of variables that make it hard to answer the question, “How fast can a catamaran go?”

Polar charts for each vessel can provide some clues to make a somewhat fair comparison. Polar charts are graphical plots of a sailboat’s performance in different wind conditions and at different points of sail. Manufacturers seldom publish since no two are ever perfectly alike. They are less of a boat specification and more of one sailor’s results for a particular boat. Most owners make their own polar diagrams, but they’re still a tool for those looking to get an idea of a model’s performance in the real world.

Speeds of Various Types of Sailing Catamarans

There are several distinct catamaran classes, and predicting speed means understanding what the designers were building the craft to do. You might be surprised to learn that the first “modern” catamarans popped up in the New England racing circles in the late 1800s. Nat Herreshoff’s Amaryllis is particularly famous from the time .

Since then, catamarans have been synonymous with speed. But in today’s world of many different multihull designs, it’s important to set your expectations accordingly. As you would not buy a Ferrari for its cargo space, don’t expect your minivan to win any races at the track.

Examples of cruising cats include popular models made by the big-three catamaran makers—Lagoon, Fountaine Pajot, and Leopard. However, there are dozens of other companies making these boats. The market and industry for cruising catamarans have never been larger. 

Most of these boats are engineered to provide comfortable accommodations for voyaging. They first became famous as vessels for sail charter holidays, where their huge cockpits and private cabins made them much more popular than the smaller and cramped monohull options.

As a result, they’re not built with high-tech components or super lightweight performance rigs. Instead, they’re the catamaran equivalent of a Hunter or a Catalina sailboat—mass-produced on an assembly line. That keeps prices lower than other types of catamarans, but it also means that they’re not winning any races. The makers use traditional layups with end-grain balsa-cored fiberglass to keep costs down. In addition, they usually feature stub fin keels, which are foolproof to sail but will not provide the upwind performance of a lift-making daggerboard. 

Still, without ballast and when lightly loaded, cruising catamarans can move. They show their colors in light air when heavy displacement-hulled sailboats usually make their poorest showing. Since these moderate conditions also make for great cruising, these boats can provide a lovely ride in smooth weather. 

Cruising catamarans can’t plane or anything, but their narrow hulls create an effect that means they can beat the hull speeds of a similarly sized monohull. Of course, it’s not a precise number since every boat and crew is different, but generally, you could expect speeds to be about one and a half times that of a same-sized monohull.

These catamarans are still rigged for comfort, but they’re built using the highest-quality and lightest-weight materials. While their hulls are rigged for comfortable living, they are generally designed much sleeker than regular charter-style cruising catamarans. The hulls are narrower, and you’re unlikely to see tall flybridges or forward lounge seating.

Several companies are making these boats. But in the world of catamarans, a performance cruiser is the upper end of the market. If you want a car comparison, Lagoons are something like a Chevy sedan, whereas an Outremer is like an M-series BMW. A Gunboat would be even more exotic, like a Ferrari. Not only are they more fashionable brands, but they’re also made to higher standards with cutting-edge designs . 

It’s also worth noting that the category of “performance cruising cat” is a sliding scale. Some companies make vessels with better materials and craftsmanship than the cruising cats but aren’t designed for speed. Others build cats that are all about performance with few amenities. 

With every new model, companies building these cutting-edge boats are attempting to boost the “performance” and the “cruising” aspect of their vessels. As a result, amenities and speed continue to get better and better. 

Any racing sailboat is not designed for comfort. Especially on a catamaran, accommodations take up space and weigh the boat down. True racing vessels are designed to not worry about the crew but optimize every element for speed. Once the boat is designed for the desired performance, they’ll squeeze in bunks and storage wherever they can. 

As such, there’s not much point in comparing them to liveaboard or cruising sailing vessels—they are too different. Some modern racing catamarans even fly above the water on foils. This makes for a high-speed boat and a considerable risk for sailors traveling for pleasure. Gunboat tried to make a foiling cruising cat in the G4 model, but it didn’t go so well for them. 

Power cats run the same gamut of designs that sailing catamarans do. Power catamarans and sport catamarans designs are popular in powerboat circles for the same reasons they are in the sailing world–their hull designs allow for smaller underwater profiles and high speeds. There are many fast catamarans out there with twin engines and average speeds of well over 70 knots. Most recreational vessels cruise at about 20 knots, however.

Power catamarans also offer a smooth ride, making them a popular choice for large vessels like passenger ferries. There are even military vessels that use two hulls, like the stealth M80 Stiletto .

As you can see, catamaran speeds vary from just slightly better than monohulls to extraordinary flying machines. But cats are about much more than just speed. Their open and bright living space makes living aboard an entirely different experience than living on a monohull. Their cockpits flow into their salons for a full-time outdoor living feel that no other type of vessel can match. There are many reasons to choose a catamaran as a liveaboard sailboat.

How fast is a catamaran?

The answer depends on many other questions, like what sort of catamaran is it? And if it’s a sail cat, how fast is the wind blowing? 

Sailing catamarans come in all different shapes and sizes. Some are optimized for living space and comfort, while others are designed with fast cruising speeds being the sole goal of the boat. The Gunboat 68, one of the fastest cruising sailboats currently made, can exceed 30 knots. 

The world of power cats is much the same. Some power cats can do well over 70 knots, while most cruising boats top out at around 20 knots.

Do catamarans have a hull speed?

A hull speed is a characteristic of traditional displacement-hulled sailing vessels. The properties of the hull shape under the water create drag that limits the overall speed that the vessel can achieve. Even if you keep adding more power (or more wind), the vessel cannot exceed its designed hull speed for any length of time. Hull speed is a factor of waterline length. 

Multihulls, however, have an entirely different underwater profile than monohulls. Their narrow hulls and shallow keels mean that drag is not the limiting factor. With this in mind, designers can tweak catamaran hulls to plane and cruise well above the hull speed of a similarly sized monohull.

What is the fastest cruising catamaran?

The market for fast-moving cruising cats has never seen more innovation than in the past decade. This type of boat has taken off, spurred in part by new designs and the overall popularity of multihulls for cruising. The industry leader in fast multihulls is generally considered the French-based company Gunboat . After all, one of the company’s mottos is “Life is too short to sail a slow boat.”

The company’s largest boat to date is the Gunboat 90 Sunshine . However, the delivery of the company’s current flagship, the Gunboat 68 Condor , from France to St. Maarten, provides some real-world numbers. In the delivery crew’s words, “Our max speed exceeded 30 knots a couple of times, and the max 24-hour run was 328 nm.” To save you the math, that works out for an average speed of 13.7 knots for their best day.

Matt has been boating around Florida for over 25 years in everything from small powerboats to large cruising catamarans. He currently lives aboard a 38-foot Cabo Rico sailboat with his wife Lucy and adventure dog Chelsea. Together, they cruise between winters in The Bahamas and summers in the Chesapeake Bay.

How Fast Do Catamarans Go? 5 Examples (With Pictures)

A catamaran is generally more balanced on the water and can be faster than a multi-hull vessel.

Unless you compare them to foiling monohulls like the new America’s Cup boats that sail at over 50 knots, they are not recreational vessels.

In this article, we will look at how fast each type of catamaran will go.

Table of Contents

Here are the numbers before we dive into the details:

Average Speed For Sailing Catamarans

Catamarans can vary in size from 14 ft to over 100 ft. Catamarans can come in a wide variety of design types.

Sailing Catamarans have been attempting to make advancements over their mono-hulled counterparts.

These advancements include:

• Foils that assist with lifting the vessel out of the water.
• Stability advancements.
• Racers that can maintain their speed while out in the ocean.

3 Different Types of Sailing Catamarans:

1) sport catamarans.

One type of sailing catamaran is a sport catamaran, which is otherwise known as recreational. These are typically supposed to have a small crew and launch and land on beaches.

Sport catamarans do not normally have living quarters and are ideal for day trips. Resorts or other rental services often use these.

These can also be used for racing.

Sport vessels have been known to travel over 30 knots but can speed over 40 knots in the proper conditions.

2) Cruising Catamarans

Another type of sailing catamaran is a cruising catamaran. These often come with complete living accommodations, so they sacrifice speed over their sportier counterparts.

They can average between 9 and 10 knots, depending on the conditions. The top speed is typically around 15 knots.

It would be best if you were careful with catamarans that have living quarters. The more you weigh it down, the less speed you will have.

3) Racing Catamarans

The final type of sailing catamaran is an ocean racing catamaran.

These boats are large and can reach over 100 feet in length.

The top speed of this type of catamaran is around 45 knots.

Because of the prize money for entering these in races, much research goes into their advancement.

Average Speed Of Power Catamarans

Catamarans with power motors fill a different type of boating category.

These are commonly used when speed and smoothness are favored over space or capacity.

Because of their stability, catamarans are good vessels for combating seasickness as well as transportation. We have a separate article here with all you should know about catamarans and (how to overcome) seasickness .

On a commercial level, these can be used for ferries for both people and vehicles. They are used for short term travel, often to or from islands.

Like sailing catamarans, there are a few types of power catamarans.

1) Power Cruising Catamarans

Similar to sailing cruising catamarans, they also have power cruising catamarans. These also have living quarters and are stable while out on the water. The speed of these vessels highly depends on the motors equipped and the size of the boat itself.

Like passenger transport or ferries, catamarans have a high speed of about 40 to 70 miles per hour.

These are made to travel at great speeds to allow their commuters the shortest possible ride to their destination.

The military also utilizes power catamarans. They use power catamarans to transport military cargo. These ships are ideal because of their speed, holding capacity, and ability to venture into shallow ports.

2) Swath Catamarans

They also have small-waterplane-area twin-hull vessels. These are called SWATHs.

These differ from the average catamaran because they also have submarine-like hulls that stay completely under the water.

Due to the hulls being submerged, they are not normally affected by waves. These are used most often in the ocean as research vessels. They can also be used for certain types of yachts. Because of their stability, they are good vessels for furniture that will not require as much securing.

These often travel between 20 and 30 knots.

Some catamarans are designed for wave piercing. These are made to pierce through waves rather than sail over them, causing them to be faster. These can be used as passenger ferries, yachts, and military vessels as well.

3) Whitewater Catamarans

There are also recreational catamarans made for whitewater travel. These are sometimes called “cata-rafts.”

They are made using two inflatable hulls connected with a scaffold. These are lightweight and perfect for whitewater sports.

They are even able to be packed away in a backpack. They can take up to 20 minutes to assemble, including inflation.

They have high speeds on white water rivers and can be most compared to a canoe, kayak, whitewater raft, or other white water vessels.

Performance Characteristics Of Catamarans

Catamarans require four times the power to double their speed. A mono-hull vessel, however, would require eight times the power to double their speed.

This is because a Catamaran has less resistance in the water.

This is also good for conserving and using less energy.

Catamarans are also more stable in the water. This stability is effective at resisting heeling or capsizing. A multi-hull vessel would require four times the force to capsize as a similar-sized mono-hull vessel.

The general sailing in a catamaran is smoother and allows for activities that are not always possible on a mono-hull sailboat.

Are Catamarans Faster than Mono-Hull Vessels?

Because catamarans have less water resistance, they are generally faster than mono-hull vessels.

This is because their hulls are smaller, which means they have a smaller bow wave to fight.

A bow wave is a wave created by the displacement of water by the bow of a ship. After a certain speed, a boat has to start hauling itself over its own bow wave.

The larger hull a ship has, the larger its bow wave will be and the more power required to fight it.

Catamarans have two small and narrow hulls, so they do not have much of an issue with their bow wave. This is one reason they are usually faster than a similar-sized mono-hull vessel.

Catamarans can be between 20-30 percent faster than their monohull counterparts.

Issues with catamarans over mono-hulls are that they can take more time to turn.

How Is The Speed Measured?

Boats commonly measure speed using GPS tracking devices to measure distance traveled. Speed while sailing is measured in knots. A knot is one nautical mile per hour, which equals about 1.15 miles per hour.

How Fast Are Catamarans Compared To Other Boat Types?

• Sailing catamarans typically average about 10 knots.
• Pontoon boats average about 20 mph.
• A powerboat cruiser can average anywhere between 30 and 50 mph.
• Cigarette boats can even reach close to 90 mph in the proper conditions.
• Sailboats average between 6 and 12 mph depending on wind conditions. This includes mono-hull between 6 to 8 mph and catamarans and trimarans between 9 and 10mph

Two different factors can determine the speed of sailing ships:

1) The hull type as listed above.

Different hulls rest in the water more or less than other types. The less of the hull that is underwater, the faster it can go.

This is because the less of the hull in the water, the less drag created while sailing.

2) The length of the boat

The longer the boat, the faster it can go. Every boat has a maximum hull speed that cannot be exceeded unless the boat can plane on the water’s surface or be lifted on hydrofoils.  For most boats, the longer the boat, the higher the maximum hull speed is.

Speed Vs. Comfort Considerations For Catamarans

If you are looking for a catamaran, you have a lot of options.

You can choose to prioritize speed or comfort.

After deciding to purchase a catamaran, the type of catamaran you should look at depends on where and what you are using it for.

You will want to make sure that you look at what type of water you will be traveling in, how many people you are traveling with on average, and what type of speed you hope to achieve.

One thing you will want to keep in mind before the purchase of a catamaran is storage. If you intend to store your boat in a marina, you are often charged for two slips due to the beam, or width, of a catamaran versus the standard mono-hull vessel.

Catamarans can be beneficial for those who get seasick because they offer a steadier ride and the ability to have more open air space. Because the living quarters are not inside the hull and under the water’s surface, you have more windows and visibility.

Both sailing and power catamarans are viable options. Also, sailing catamarans can come with back-up power engines for low winds or situations such as docking in a marina.

Catamarans that have twin engines can offer more control and precision than those on a mono-hull vessel. This is good for tight and busy areas or navigating marinas.

Overall, there are plenty of options for you, and they offer many benefits over their mono-hull counterparts.

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Mastering Catamaran Sailing: Essential Guide & Tips to Navigate the Waters

Alex Morgan

Sailing a catamaran can be an exhilarating and enjoyable experience for both experienced sailors and beginners alike. Unlike monohull sailboats, catamarans offer unique advantages in terms of stability and speed. If you’re interested in learning how to sail a catamaran, it’s important to understand the basics and master the necessary skills. This article will provide you with a comprehensive guide to sailing a catamaran, from understanding the fundamentals to maneuvering and handling the boat effectively.

To begin with, let’s delve into the introduction of sailing a catamaran, followed by understanding the basics of a catamaran. We’ll explore what exactly a catamaran is and how it differs from a monohull sailboat. we’ll discuss the advantages of sailing a catamaran, highlighting why it has become a preferred choice for many sailors.

Before setting sail, proper preparation is essential. This section covers the importance of safety equipment and checks, along with understanding wind and weather conditions. Planning your route is crucial to ensure a smooth and enjoyable sailing experience.

Once you’re prepared, we’ll move on to the essential sailing techniques for a catamaran. This section will guide you through rigging and hoisting the sails, tacking and jibing, trimming the sails, and controlling speed and direction. Mastering these techniques is key to maneuvering the catamaran effectively on the water.

Handling the catamaran also requires specific techniques. We’ll cover important maneuvers such as docking and undocking, mooring and anchoring, and addressing emergencies like man overboard recovery. These skills are vital to ensure a safe and successful journey.

We’ll provide you with essential safety tips for sailing a catamaran. Understanding right-of-way rules, handling rough seas and heavy winds, and maintaining balance and stability are crucial aspects of staying safe on the water.

By the end of this comprehensive guide, you’ll have a solid understanding of how to sail a catamaran and be well-equipped to embark on your own catamaran adventures while ensuring a safe and enjoyable experience.

– Sailing a catamaran offers the advantage of maximizing space with its two hulls, allowing for more comfortable living quarters and a larger deck area. – Catamarans provide a stable and balanced sailing experience, making them a safer option for beginners and those prone to seasickness. – Proper preparation, including checking safety equipment, understanding weather conditions, and planning your route, is crucial for a successful catamaran sailing experience.

Understanding the Basics of a Catamaran

Understanding the basics of a catamaran is essential for safe and enjoyable sailing. A catamaran is a boat with two parallel hulls connected by a deck. It has advantages over monohull boats. Catamarans are stable due to their wide beam, reducing the risk of capsizing . They can access shallow waters because of their shallow drafts . Catamarans also offer more space and comfort with larger cabins, living areas, and deck space.

To control a catamaran, the skipper uses the helm to control the rudders. Adjusting and trimming the sails allows the skipper to use the wind’s power and steer the boat efficiently. Balancing the sails and maintaining stability while sailing is important.

Knowing the key components, how to control the boat, and handle the sails will help you navigate the waters confidently. Whether you’re a seasoned sailor or a beginner, familiarizing yourself with the fundamentals of catamarans is crucial.

What Is a Catamaran?

A catamaran, also known as a cat , is a type of boat that features two parallel hulls connected by a platform or bridge deck. This unique design provides it with stability and speed, making it a popular choice for sailing enthusiasts. Unlike traditional monohull sailboats, a catamaran offers a wider beam , which results in more space and greater stability . As a result, the sailing experience on a catamaran is smoother and more comfortable .

There are several advantages to sailing a catamaran. One significant advantage is its shallow draft , which allows it to navigate in shallower waters that are inaccessible to other types of boats. The dual hull design of a catamaran minimizes drag and enhances speed , making it highly efficient for long-distance cruising . The spacious interior layout of a catamaran provides ample room for accommodations , amenities , and storage .

When sailing a catamaran, it is essential to consider the wind and weather conditions for safe navigation. Understanding the right of way rules and knowing how to handle rough seas and heavy winds are crucial skills for catamaran sailors. Maintaining balance and stability is of utmost importance to ensure a smooth sailing experience.

A fun fact about catamarans is that they have been utilized by Polynesian cultures for centuries, proving their effectiveness and versatility in various sailing conditions.

How Is a Catamaran Different from a Monohull Sailboat?

A catamaran is different from a monohull sailboat in several ways. A catamaran has two parallel hulls connected by a deck or bridge, whereas a monohull sailboat only has one hull. This dual hull design provides greater stability and balance on the water.

In addition, the hulls of a catamaran are wider and shallower compared to those of a monohull, allowing for a shallower draft and improved maneuverability . This also results in a higher cruising speed and faster sailing speeds for catamarans.

Catamarans also offer more interior space and are known for their spaciousness and comfort , thanks to their wider beam. When sailing upwind, catamarans experience less heeling , which translates into a smoother and more comfortable ride for passengers.

Catamarans are better suited for cruising in shallow waters and can anchor closer to shore due to their shallow draft . The dual hull design of catamarans also provides greater redundancy and safety in the event of hull damage or collision.

Unlike monohull sailboats, which typically have a keel, catamarans rely on centerboards or daggerboards to prevent sideways sliding. The main differences between a catamaran and a monohull sailboat lie in their stability , speed , comfort , and maneuverability .

Advantages of Sailing a Catamaran

– Stability: Catamarans offer excellent balance with their twin hulls, making them less likely to tilt or capsize compared to monohull sailboats.

– Spaciousness: The wide beam of catamarans provides more interior and deck space, including comfortable living quarters, larger cabins, and ample room for socializing and entertaining.

– Speed: The design of twin hulls reduces drag, allowing catamarans to sail faster and provide exhilarating experiences.

– Shallow Draft: Catamarans have a shallower draft than monohull sailboats, enabling them to sail in shallower waters and access a wider range of cruising grounds.

– Comfort: The wide beam and stable design of catamarans offer a smoother and more comfortable sailing experience, eliminating the heeling common in monohull sailboats and reducing the chances of seasickness.

– Maneuverability: Catamarans are more maneuverable than monohull sailboats, providing better turning ability for navigating tight spaces, docking, and anchoring precision.

– Sailing Performance: Catamarans excel in light wind conditions, thanks to their large sail area and light weight, allowing them to catch even the slightest breeze and maintain good boat speed. This makes them ideal for destinations with calm weather patterns.

Preparing for Sailing a Catamaran

Preparing for a thrilling catamaran sailing adventure requires careful planning and essential knowledge. As we dive into the section on “ Preparing for Sailing a Catamaran ,” we’ll explore vital aspects such as safety equipment and checks , understanding wind and weather conditions , and planning your route . Get ready to uncover expert tips and strategies to ensure a smooth and enjoyable catamaran journey on the open waters.

Safety Equipment and Checks

Prioritize safety when sailing a catamaran. Thoroughly check and prepare your safety equipment before setting off on your adventure. Consider the following important safety equipment and checks :

• Life jackets: Ensure enough properly fitting life jackets for everyone on board.
• Flotation devices: Have throwable flotation devices readily available for emergencies.
• Fire extinguishers: Have the appropriate type and number of fire extinguishers on board.
• First aid kit: Maintain a well-stocked kit for handling minor injuries or medical emergencies.
• Navigation lights: Ensure all navigation lights are functioning properly, especially for sailing at night or in low visibility conditions.
• Communication devices: Carry reliable communication devices such as a marine VHF radio or satellite phone for calling for help if needed.
• Engine and safety equipment checks: Regularly inspect engines, bilge pumps, anchor systems, and other safety equipment to ensure good working condition.

Remember, safety is crucial. Check your safety equipment before every trip and ensure proper working order. Familiarize yourself with specific safety requirements and regulations of the sailing area. By taking these precautions, you can enjoy your catamaran sailing adventure with peace of mind and be prepared for any unexpected situations.

Understanding Wind and Weather Conditions

Understanding wind and weather conditions is crucial when sailing a catamaran. You must have a comprehensive understanding of the wind direction, speed, and weather changes that may impact your sailing experience. Here are some key considerations to keep in mind:

1. Wind direction: It is essential to know the direction from which the wind is blowing. This knowledge will assist you in planning your sailing route and selecting the appropriate sails.

2. Wind speed: Pay close attention to the wind speed as it could potentially affect the speed and maneuverability of your boat. Higher wind speeds may necessitate reefing the sails or adjusting your course.

3. Weather changes: Remain mindful of any approaching storms, rain, or fog. These conditions can have a significant impact on visibility and create challenges when sailing.

4. Sea state: Take note of the current sea state, which includes wave height and frequency. Rough seas may require you to adjust your sailing technique and speed to ensure the stability of the catamaran.

5. Weather forecasts: Always remember to check the weather forecasts before embarking on your sailing trip. This will provide you with an overview of the expected weather conditions.

By possessing a thorough understanding of wind and weather conditions, you can make well-informed decisions to ensure a safe and enjoyable sailing experience aboard a catamaran. Keep in mind that conditions at sea can change rapidly, so it is essential to stay vigilant and adapt your plans accordingly.

Planning Your Route

When planning your catamaran sailing route, it is important to consider several factors for a safe and enjoyable journey. One of the first things to do is assess the weather conditions by checking the forecast for potential storms or strong winds. It is crucial to avoid adverse conditions as they can pose risks to both the crew and the catamaran’s safety.

In addition, it is necessary to identify key destinations and conduct research on navigational challenges. This will help in finding suitable anchorages or marinas along the way. Creating a timeline is also essential to plan the duration of the journey, taking into account the distance to be covered and the catamaran’s speed. It is important to remember to account for any time constraints or events that may affect the plan.

Using navigational charts, it is advisable to plot the course, noting any potential obstacles along the way. It is also a good practice to plan alternative routes in case they become necessary. Considering currents and tides is another crucial aspect of route planning. Studying tidal patterns and current directions will allow for incorporating these factors into the planning process for greater efficiency.

Another important consideration is fuel and provisions . It is necessary to determine the locations of fuel stations and provisioning points along the route. Planning fuel stops and stocking up on supplies will ensure that you have everything you need during the journey. Communication and safety should not be overlooked either. Identifying channels to communicate with other sailors and emergency assistance is vital . It is also important to familiarize yourself with emergency procedures and have access to contact information in case of any unforeseen circumstances.

It is recommended to regularly review your route plan and make adjustments based on real-time conditions and feedback. This will help ensure that you are always up to date with any changes that may occur during the journey. By carefully planning your route, you can optimize your sailing experience, safely navigate waters, and fully enjoy your catamaran adventure.

Essential Sailing Techniques for Catamaran

Mastering the essential sailing techniques for a catamaran is the key to harnessing the power of wind and water. From rigging and hoisting the sails to controlling speed and direction, each sub-section in this guide will unlock the secrets that seasoned sailors swear by. So, get ready to tack and jibe , trim those sails just right, and experience the exhilaration of sailing a catamaran like a pro!

Rigging and Hoisting the Sails

To rig and hoist the sails on a catamaran, follow these steps:

1. Assemble the mast, boom, and rigging securely and properly aligned.

2. Attach the main halyard securely and tensioned to the head of the mainsail.

3. Attach the jib halyard properly tensioned and secured to the head of the jib sail.

4. Connect the main sheet to the boom to control the angle and tension of the mainsail.

5. Connect the jib sheets to the clew of the jib sail to control the angle and tension of the jib sail.

6. Attach the reefing lines to the mainsail, if applicable, to reduce sail area in strong winds.

7. Check all rigging and lines for proper tension and adjustments, ensuring everything is secure and aligned.

8. Raise the mainsail by pulling on the main halyard while guiding the sail up the mast, using winches or other mechanical aids if necessary.

9. Raise the jib sail by pulling on the jib halyard while guiding the sail up the forestay, using winches or other mechanical aids if needed.

10. Adjust the main sheet and jib sheets to achieve the desired sail shape and trim for optimal boat performance.

Rigging and hoisting the sails on a catamaran is crucial for a smooth and exhilarating sailing experience. By following these steps, you can confidently prepare your catamaran for sailing adventures.

Now, let’s appreciate the history of rigging and hoisting sails. Sailing has been a vital mode of transportation and exploration for centuries. The technique of rigging and hoisting sails has evolved from simple square sails to more efficient and versatile fore-and-aft sails used on catamarans. Today, catamarans are equipped with advanced rigging systems and modern materials that enhance speed and maneuverability. Rigging and hoisting sails remain a vital skill for sailors, connecting us to our seafaring ancestors and enabling exploration of the world’s oceans with grace and agility.

Tacking and Jibing

Tacking and jibing are essential maneuvers when sailing a catamaran. These techniques allow you to change direction and make the most of the wind. Consider these key points:

• Tacking: This maneuver is used to sail against the wind. Turn the bow of the boat through the wind to switch the sails to the opposite side. This allows you to zigzag towards your destination.
• Jibing: Use this maneuver to change direction with the wind at your back. Turn the stern of the catamaran through the wind to move the mainsail to the other side. Control the boom to prevent dangerous swinging.
• Preparation: Before tacking or jibing, ensure that the crew is aware and in a safe position for stability during the turn.
• Wind direction: Success with tacking and jibing depends on understanding the wind. Assess the wind and plan your maneuvers accordingly.
• Practice: Perfecting tacking and jibing requires practice. Start with gentle maneuvers in light wind conditions and gradually progress with experience.

During a sailing race, a crew utilized their knowledge of wind patterns and executed a flawless maneuver by tacking right before the finish line. This tactical advantage secured their victory.

Trimming the Sails

Sailing a catamaran requires mastering the skill of trimming the sails . Properly trimmed sails greatly impact the catamaran’s performance and maneuverability. Here are some important considerations for sail trimming:

1. Adjusting the tension: Properly adjusting the tension on the sails is vital for achieving the desired shape and angle. The main sail should have a slight curvature called camber , which generates lift and power. Trim the jib sail to maintain smooth airflow on both sides.

2. Controlling the angle: The angle of the sails in relation to the wind direction is crucial for maintaining optimal speed. Adjust the sheets to trim the sails closer or further from the wind based on sailing conditions and desired speed.

3. Monitoring the telltales: Telltales , small yarn or ribbon pieces attached to the sails, provide valuable airflow information and indicate proper sail trimming. Continuously observe the telltales to ensure smooth and even flow.

4. Reefing: In strong winds, reducing the size of the sails through reefing is necessary to maintain stability and control. Follow the manufacturer’s guidelines for reefing and ensure proper securing of the sails.

5. Constant adjustment: Sail trimming requires constant attention. Continuously monitor wind conditions and make necessary adjustments to optimize performance and maintain control.

Mastering the art of sail trimming leads to smoother sailing, improved speed, and enhanced overall performance on a catamaran. Practice and experience are essential for developing this skill, so head out to the water and start honing your sail trimming abilities.

Controlling Speed and Direction

To effectively control the speed and direction of a catamaran, it is important to follow these steps:

1. Sail Adjustment: Optimize the power and speed of the catamaran by trimming the sails. Utilize the mainsail and jib sheets to manipulate the sail angle, taking into account the wind direction.

2. Utilize the Traveler: Fine-tune the speed and stability by adjusting the traveler. This tool, located across the cockpit, allows you to modify the mainsail sheeting point and control the angle of the mainsail.

3. Sail Plan Modification: Alter the sail plan as necessary to either increase or decrease speed. Reef the sails in strong winds to reduce the sail area, and unreef them in light winds to allow for greater sail area.

4. Daggerboard Adjustment: Maintain stability and control the direction of the catamaran by raising or lowering the daggerboards. These adjustments contribute to achieving balance and maneuverability.

5. Rudder Tweaking: Make slight adjustments to the rudder angle using the tiller or wheel, ensuring smooth steering of the boat.

Pro-tip: Enhance your ability to control speed and direction on a catamaran through practice and experience. Continuously monitor wind conditions and make minor adjustments to optimize performance.

Catamaran Maneuvers and Handling

Get ready to conquer the waters as we dive into the art of sailing a catamaran. In this section, we’ll navigate through the thrilling aspects of docking and undocking , the essentials of mooring and anchoring , and the crucial skill of man overboard recovery . Brace yourself for a wave of practical tips and tricks that will enhance your catamaran sailing experience. So, grab your compass, adjust your sails, and let’s set sail on this exciting journey!

Docking and Undocking

Docking and undocking a catamaran can be daunting, but with the right techniques and precautions, it can be done smoothly. Follow these steps:

• Approach the dock slowly, keeping an eye on the wind and current.
• Assign crew members to handle lines and fenders for a safe docking process.
• Shift into reverse as you near the dock to slow down.
• Turn the helm to steer the catamaran parallel to the dock as you stop.
• Have crew members ready with fenders to protect the catamaran.
• Engage reverse to back closer to the dock, using brief forward bursts to maneuver if needed.
• Once close, crew members should step off the catamaran with lines to secure it to the dock.
• Secure the catamaran using docking lines , ensuring they are properly fastened and have enough slack.

True story: One summer, while docking our catamaran in a busy marina, a strong gust of wind made our docking process challenging. Thanks to our crew’s quick reflexes and knowledge, we maneuvered the catamaran safely and secured it to the dock without damage. It was a valuable lesson in being prepared for unexpected situations while docking and undocking a catamaran.

Mooring and Anchoring

Mooring and anchoring are integral skills when sailing a catamaran. It is important to consider several key points when engaging in these activities. Make sure to choose the appropriate anchor that matches the type of seabed you will be navigating. Inspect the anchor line thoroughly to ensure it is in good condition and securely attached. Next, carefully select a mooring spot in a protected area that offers solid holding ground. When approaching the mooring, take into account factors such as wind and current, and proceed slowly. To secure the boat, use mooring lines that are connected to cleats or deck fittings. Safeguard your boat from potential damage by utilizing fenders . Prioritizing safety and accounting for your boat’s unique conditions and requirements is crucial. By practicing these techniques, you can enhance your proficiency and guarantee a safe and enjoyable sailing experience.

Man Overboard Recovery

• Assess the situation: When facing a man overboard situation, it is important to stay calm and promptly evaluate the circumstances. Take into account the distance between the catamaran and the individual in the water, as well as any nearby hazards or obstacles.
• Alert the crew: Immediately inform the other crew members about the man overboard incident. This ensures that everyone is informed and prepared to provide assistance.
• Initiate the man overboard recovery process: Throw a life buoy or any floating object towards the person in the water, offering them something to hold onto. This will help keep them afloat during the recovery process.
• Turn the catamaran: Skillfully maneuver the catamaran to create a controlled loop or figure eight pattern around the individual in the water. This will slow down the vessel and facilitate their retrieval.
• Bring the person back on board: Once the catamaran is properly positioned, utilize a ladder, swim platform, or any available means to assist in bringing the person back on board. Assign crew members to provide support and ensure the individual’s safety throughout the recovery process.
• Monitor and provide medical assistance: After the person is safely back on board, promptly evaluate their condition and administer any necessary medical attention. Check for injuries, monitor vital signs, and administer first aid if needed.

Pro-tip: Conduct regular man overboard drills and practice recovery procedures with your crew to ensure that everyone is familiar with their respective roles and responsibilities. This will help reduce response time and enhance the likelihood of successfully recovering individuals in emergency situations.

Safety Tips for Sailing a Catamaran

Discover essential safety tips when sailing a catamaran in this section. From understanding right of way rules to dealing with rough seas and heavy winds, you’ll learn how to navigate challenging conditions with confidence. We’ll explore techniques for maintaining balance and stability, ensuring a smooth and secure sailing experience. So hop aboard and let’s dive into the world of catamaran sailing safety !

Understanding Right of Way Rules

Understanding Right of Way Rules is crucial for safe sailing. Follow these guidelines:

1. Sailboats have the right of way over powerboats. Be aware of your surroundings and give way to any sailboats in your path.

2. When encountering a vessel on your starboard side, yield and give them the right of way. Alter your course slightly to avoid a potential collision.

3. When overtaking another vessel, keep a safe distance and give them the right of way. Maintain a slow and steady speed to avoid creating a dangerous situation.

4. In narrow channels or crowded areas, vessels going uphill or against the current have the right of way. Yield to any vessels navigating in these challenging conditions.

5. Always be cautious and maintain a safe speed when crossing paths with other vessels. Slow down if necessary to ensure a safe passage.

By understanding and adhering to right of way rules, you can navigate the waters confidently and reduce the risk of accidents. Remember, safety should always be the top priority when sailing a catamaran.

Dealing with Rough Seas and Heavy Winds

Dealing with rough seas and heavy winds is crucial when sailing a catamaran. Here are tips to navigate challenging conditions:

1. Check the weather forecast before setting off. If rough seas and heavy winds are expected, consider delaying your trip or changing your route.

2. Ensure all crew members wear appropriate safety gear, such as life jackets and harnesses. Secure loose items on the deck.

3. Maintain a steady speed when encountering rough seas to keep the boat stable. Avoid sudden changes in direction or speed.

4. Adjust your sails by reefing to maintain control and prevent overpowering by strong winds.

5. Be cautious when navigating large waves. Approach them at a slight angle to minimize the risk of capsizing. Maintain a firm grip on the helm.

6. Be aware of the sea state. Avoid crossing large waves head-on; instead, cross them diagonally or at a slight angle.

7. Communicate effectively with your crew. Assign roles and responsibilities to ensure everyone is working together for safety and control.

In rough seas and heavy winds, safety should be the top priority. Stay alert, remain calm, and rely on your training and experience.

Pro-tip: Consider advanced sailing courses or consulting experienced sailors to enhance your skills and confidence in dealing with rough seas and heavy winds.

Maintaining Balance and Stability

Maintaining balance and stability is absolutely crucial when sailing a catamaran. It is important to ensure that weight is evenly distributed on both sides of the catamaran in order to achieve stability .

One way to accomplish this is by having passengers and crew members move to the opposite side when the wind picks up. Another key aspect of maintaining balance is properly trimming the sails to adjust their angle in response to wind changes. This helps to prevent excessive heeling and ensures stability .

Paying attention to the centerboards can greatly enhance stability . Deploying the centerboards can counterbalance the force of the wind and prevent tipping over.

Steering also plays a significant role in maintaining balance. It is crucial to steer steadily and in a controlled manner in order to keep the catamaran on course and avoid any imbalance.

It is important to be aware of weather conditions and understand how they can impact stability . When faced with heavy winds and rough seas, it is essential to adjust sailing techniques accordingly and make any necessary adjustments to maintain balance and stability .

Some Facts About How To Sail Catamaran:

• ✅ Sailing a catamaran requires adjusting to the different motion and sail trimming compared to monohull sailboats.
• ✅ Catamarans provide more space and stability compared to traditional monohull sailboats.
• ✅ Catamarans do not heel like monohulls, providing a less tiring sailing experience.
• ✅ Catamarans can sail in shallower places and prevent rolling in anchorage due to their lower drafts.
• ✅ The American Sailing Association (ASA) offers a specific course, ASA 114: Cruising Catamaran, to provide practical sailing skills and confidence when sailing a catamaran.

Frequently Asked Questions

1. how do i sail a catamaran.

Sailing a catamaran involves adjusting to its different motion and sail trimming compared to monohulls. You’ll need to take a sailing course or gather practical sailing skills to ensure confidence and enjoyment while sailing a catamaran. The American Sailing Association (ASA) offers the ASA 114: Cruising Catamaran course designed specifically for individuals with monohull cruising experience transitioning to catamarans.

2. What are the advantages of sailing a catamaran?

Catamarans offer numerous advantages over monohulls. They are more spacious, providing larger living areas above decks and expansive cabins located in the hulls. Catamarans are incredibly stable, making them ideal for longer voyages and providing maximum comfort and relaxation. They also have lower drafts, allowing navigation in shallow reef passages and anchoring closer to shore. Catamarans do not heel like monohulls, providing a more comfortable and less tiring sailing experience.

3. How can I charter a catamaran from The Moorings?

The Moorings offers innovative and top-quality catamarans for sailing vacations. To charter a catamaran from The Moorings, you can visit their website and access their charter resources. They are known for their exclusive access to Robertson & Caine catamarans, distinguished for their quality and comfort. There, you can find information on boat availability, reputation, and customer reviews to choose the right catamaran for your needs and preferences.

4. What is the ASA 114: Cruising Catamaran certification?

The American Sailing Association (ASA) offers the ASA 114: Cruising Catamaran certification. This certification is designed for individuals with monohull cruising experience who want to transition to catamarans. The course covers the advantages and disadvantages of multihull sailing, as well as practical sailing skills specific to catamarans. Obtaining this certification ensures that you have the necessary knowledge and skills to confidently sail a catamaran.

5. Are catamarans safe for offshore sailing?

Yes, catamarans are safe and stable for offshore sailing. They are designed to offer stability and comfort in various conditions. Catamarans have two independent hulls, making them less likely to sink completely. They also have duplicate navigation systems, including two engines and rudders, for onboard safety. Catamarans remain stable even in bad weather and do not capsize easily. Their advanced design and safety features make them a reliable choice for offshore sailing.

6. Can I sail a catamaran without previous sailing experience?

Sailing a catamaran without previous sailing experience is not recommended. It is essential to have some sailing knowledge and skills before attempting to sail a catamaran. Taking a sailing course, such as the ASA 114: Cruising Catamaran course, will provide you with the necessary skills and confidence to safely operate a catamaran. Spending time onboard and obtaining a sailing diploma or certification will ensure a better understanding of catamaran sailing fundamentals.

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Advantages of Catamarans and Catamaran Hull Speeds Calculation

• Categories : Marine history
• Tags : Marine engineering

What is a Catamaran?

Before going into the advantages of catamarans, I’d just like to define the term. Catamarans are a class of boat that has two hulls, generally equal in size. The hulls are connected by a structure of some sort. Catamaran hull speeds are very high, making them a good choice for recreational uses. Catamaran sailboats are common, but catamaran ferry designs are quickly growing in popularity due to their unique advantages.

The catamaran is a ship design with an interesting history. The twin-hull design was first observed by Europeans in India in the late 17th century, but it was actually invented by South Pacific islanders. The capabilities of catamarans were more or less ignored in the West until 1877, when an American named Nathanael Herreshoff began developing and racing catamarans. His designs were so much faster than traditional monohull designs that sailing authorities banned them from competition for nearly a century. Today, catamarans are a popular design for recreational and racing sailboats, and are being used in efficient, low-wake ferries .

Image: Flickr , Catamaran in Cozumel.

Advantages of Catamarans

Catamarans are, in general, faster than single hull boats. This is due to several factors, the most important of which is the hull shape. Displacement hulls are the most common shapes for single hull craft. A displacement hull is supported on the water entirely by buoyancy effects. This creates a hydrodynamic drag barrier, which slows the craft. Catamaran hulls can be designed as planing or displacement hulls, but they are not slowed nearly as much by the drag barrier. Catamarans reduce drag by making use of a very thin and pointed hull design.

Catamarans are also very light, which further reduces drag and displacement. Catamarans save on weight because the multihull design eliminates the need for a keel counterweight, as the same purpose (righting the ship) is served by the hull spacing. This can make them difficult to turn, however.

Catamarans are also more stable than monohull ships, enabling designers to use more sail per foot of the boat. Stability comes from the wide beam legth; beam length is the distance from one side of the boat to the other. This wide beam and stability also allows catamarans to gain more power from heavy gusts, because they do not tend to heel over like monohulls do.

Catamaran Hull Speed

More efficient single hull boats are designed to travel with a low Froude number, which reduces but does not eliminate the drag barrier. This drag limits hull speed based on a relation involving length at waterline, given by the formula V=(gL/(2pi))1/2, where g is the gravitational constant and L is the waterline length. This is the theoretical limit for single hull displacement craft. Note that ships can sometimes exceed this theoretical limit, but to do so requires a very large power source.

The calculations for a catamaran are more complicated. The formula for catamaran hull speed is 1.34*(wetted length)1/2; however, this drag formula is generally not the limiting factor for catamaran hull speed. This is because boats with waterline length to beam ratios greater than 8:1 are not limited by hydrodynamic drag factors, whereas smaller boats need to plane to do so (planing requires enormous amounts of power for displacement hulls). A more important factor to consider is the prismatic coefficient, Cp. Cp = V/(LBP*Am), where V is the volume of water displaced by the hull, LBP is the length between perpendiculars, and Am is the area at midship.

Very fast boats actually require a high prismatic coefficient, which in turn requires a less-narrow boat. However, narrower hulls can get away with a lower prismatic coefficient. The ideal range of Cp for a catamaran is between 0.61 and 0.65. There are a few ways of increasing the prismatic coefficients: sailors can use bulb bows, a wide planing aft segment, or a flat hull rocker in conjunction with a bustle aft. Though high prismatic coefficients increase drag at low speed, at high speeds they can reduce drag by as much as ten percent.

Catamaran Hulls and Low-Wake craft.

As explained here , catamarans can be used to create low-wake ferries. Because of their wide bows and low weights, catamarans can be made to travel quickly with minimal wake. Catamaran ferries are also more fuel-efficient, because of the previously-mentioned factors.

Image Credit: Wikimedia Commons , Catamaran Ferry

Catamaran Boat Design

Hull Speed Calculations

Catamaran Hull Comparisons

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Catamaran Hull Speed

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The hull speed formula for displacement monohulls is 1.34 x the square root of the waterline length. When planing, a monohull will exceed it's hull speed. Obviously this formula doesn't apply to catamarans. Even when not planing, they will travel much faster than what the hull speed formula predicts. Is there a formula or general guideline for catamaran hull speed related to waterline length and / or hull length:beam ratio?  

Here, read this ...  

Few Catamarans are actually planning vessels. Most are semi-displacement boats (like most modern IMS/IRC derived monohulls). Both forms of semi-displacement boats achieve speeds that are higher than normal hullspeed (i.e. 1.34 x the square root of the waterline length) by minimizing wave production. In the case of multihulls, this is done through a very narrow waterline beam to length ratio, and minimal interference between the waves produced by the other hull(s). Semi-displacement mono-hulls cheat a bit by using very fine entries to minimize the size of the bow wave that they produce. In both cases, clean hull forms and minimal drag is critical to overall performance, but properly designed, semi-displacement boats can achieve sustained speeds that can literally exceed twice their theoretical hull speed without planning. Of course as Alex points out, and as the article that he linked to explains, few cruising cats achieve passage speeds that exceed or even match those of modern performance mono-hull cruising boats. Respectfully, Jeff  

Thanks guys.  

Damn multis. They leave me standing.  

Under body shapes: keels and centerboards, Beam & hull-beam ratios, Beam overall – overall wide beam versus standard beam, Displacement but I can`t find any mention of the optimal hight of the bridge deck cabins, Giuliettas post mentions under deck clearance and it`s extremely important but if you build the bridge on top off the bridge deck would that make it extremely unstable as the center of gravity would be to high making the cat useless in any swell.  

sctpc said: Under body shapes: keels and centerboards, Beam & hull-beam ratios, Beam overall - overall wide beam versus standard beam, Displacement but I can`t find any mention of the optimal hight of the bridge deck cabins, Giuliettas post mentions under deck clearance and it`s extremely important but if you build the bridge on top off the bridge deck would that make it extremely unstable as the center of gravity would be to high making the cat useless in any swell. Click to expand...

Yes but what would the optimal height formula be I have been reading for over 4 hours since I read this post and lots of designers mention it but is there a rule to it, 'deck should be 2 foot making cabin 9 foot for a 30 foot cat or deck 4 foot cabin roof 10 foot for a 50 foot cat. I find it interesting that all the other design stuff is quite well out explained but none on windage problems ect.  

The less cabin, the better from a windage and weight standpoint. There are various rules of thumb for bridgedeck clearance. .06 x DWL is one. As far as hull waterline beam goes, some say 16 to 1 is as good as it gets from a resistance standpoint. A fast cruiser will be about 12 or 13 to 1, but the shorter the boat, the more beam there will be in the hulls in order to get a reasonable amount of room inside and carrying capacity. 8 to 1 hull beam to DWL length is common in small to medium size cruising cats. Overall beam is usually about one half of the overall length. Recent designs are often somewhat beamier overall-BOA 55% of LOA is not uncommon now. Tim Dunn - 65 Foot Sailing Catamaran Design by Tim Dunn  

there isn't a basic rule for bridge deck clearance and cabin height. Some designers avoid the problem entirely by not using the bridgedeck form living accommodations. Wharram's design often don't have any living space on the bridge deck.  

Check out Performance Cruising Inc. - The Official Gemini 105MC and Telstar 28 Web - I find the boat to be a best of both worlds design in a smallish cruising catamaran. I am of course partial and biased. The hulls are roughly 8:1 length: beam. I've had mine at 10.3 knts SOG in 16 knts on a close reach (50 degrees off the wind) going up current in 1.25 knts of current. Other owners have reported (and photographed) top speeds of 18 knts, and routinely get 10+. From the side the gemini looks like a moderately high windage mono. That's hard to do with a queen sized bed in the master cabin and twin staterooms aft with double beds. It has 39 inches of clearance at the front it takes chesapeake chop well on the nose, but with only 18 inches at the stern we do get the occasional 'thumb' on the floor of the cockpit. Reportedly they do well in typical ocean swell and have crossed the Atlantic and Pacific Ocean quite well. Several reside in Hawaii, having sailed there on their own bottoms, a couple are currently circumnavigating ( theslapdash.com . By making the salon area standing height for only the walk in area and sitting height at the salon table Tony Smith (the designer) was able to give it a nice profile. Otherwise, headroom is 6'2" throughout. I routinely dock my boat in a cross wind of 5 or so knots and I can tell you it parks and tracks as surely as a car with very little problem caused by windage. Mine:  

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Fixed it, thanks.  

Bridge deck, pounding, and windage So, 3 feet between the bottom of the bridge deck & the deep blue sea. In some cases long and thin is good but can it be taken to extremes? For example a 50' cat with a waterline beam of 2.5' mathmatically will produce a vapor trail at 35+ kts. In reality though, will it? Since I hate doing time in the hulls of any boat I am going to keep the boat light in terms of gear and have a tapered bridge deck encompassing all accomodations with a profile to the wind of about 3'. Add a nice sail plan and I'm having fun! Or at least that is the current plan. So, any thoughts on the long skinny hull thing?  

One other point is the overall beam of the boat, especially in the case of a catamaran matters as well. If the beam is relatively narrow for the boat size, the hull wake from the two hulls can interfere with performance.  

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