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Schionning Designs International Pty Ltd Leaders in Multihull Design and Kit Development.

The Kit Process

Building your own boat can be a daunting prospect, however to demonstrate each step in the kit assembly process, we've created this guide for you to study. as you can see our kits are the ultimate in building efficiency and have been streamlined over 30+ years to ensure that you're on the water faster and with less effort., how does it all go together.

Schionning Designs Catamaran Kit Build Process - Step 1 The first step to building your dream catamaran begins with a strongback - this is a square frame used to position the temporary frames that will be used to form the hull shape. This frame will be set up and must be square and accurate, a string or laser level can be used to achieve this.

The first step to building your dream catamaran begins with a strongback – this is a square frame used to position the temporary frames that will be used to form the hull shape. This frame will be set up and must be square and accurate, a string or laser level can be used to achieve this.

Step 2 pre-cut frame panels are erected along the strongback in sequence - catamaran building step 2 SDI

The forebeam is now installed along with the striker attachment fitting, as shown above. The bridgedeck is installed shortly after and taped onto the bulkheads with webs installed, this now completes what is a quite stiff and strong platform to work on.

Step 8 catamaran kit building - forward webs and dash will be fitted - SDI

Now that the bridgedeck is in place, the forward webs and dash will be fitted. At this stage, all furniture and internal work begins, with the main panels left off for ease of access when working.

Catamaran Kit Building Processs by Schionning Designs SDI -Step 9 The internal furniture is now installed, if you chose Kit Option 2, this furniture will be pre-cut to your previously decided upon layout. If you chose to receive blank panels, this is the period in which your internal living areas are to be built. This construction uses paper-honeycomb Duflex panels, as these are superior in weight when used non-structurally. Cabin soles, engines and daggerboard cases are also now installed.

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How to Build a Catamaran Boat? (Step-by-Step Guide)

diy catamaran hulls

Building a catamaran boat from scratch is a rewarding and challenging endeavor.

It takes a combination of skill, dedication, and hard work to craft a seaworthy vessel.

In this step-by-step guide, you’ll learn how to design and size your catamaran, gather the necessary materials, cut and assemble the pieces, lay fiberglass and apply epoxy, make finishing touches, add hardware and paint, and rig the boat.

With the right tools, planning, and patience, you can make your dream of sailing in a catamaran a reality.

Table of Contents

Short Answer

Building a catamaran boat requires a lot of patience and skill.

The first step is to choose the right materials for the hull, such as fiberglass, wood or aluminum.

Then, you will need to build the frame of the boat, which includes the crossbeams and the main hull.

After that, you will need to install the decking, the rigging, and other components.

Finally, you will need to paint and varnish the boat, as well as install the outboard motor and other accessories.

Design & Size Considerations

When it comes to building a catamaran boat from scratch, the first step is to determine the design and size of the boat.

This should take into account the intended use of the boat, such as sailing, fishing, or leisurely cruising.

The size of the boat will depend on the number of passengers and the type of activities the boat will be used for.

For instance, a larger boat may be needed if passengers will be standing or participating in watersports.

The design of the boat is also important and should be chosen based on the intended use.

If you are looking to build a sailboat, you will need a design that is optimized for sailing.

On the other hand, if you are looking to build a fishing boat, you will need a design that is optimized for fishing.

There are a wide variety of boat designs available, so it is important to research and choose the one that best suits your needs.

In addition to the design and size, you will also need to consider the materials used for construction.

The most common materials for building a catamaran boat are wood, fiberglass, and epoxy.

Each material has its own advantages and disadvantages, so it is important to research them and determine which one is best for your project.

Finally, you will need to consider the cost of the project.

Building a catamaran boat from scratch can be a costly endeavor, so it is important to have a budget in mind before you begin.

The cost will depend on the type of materials used and the complexity of the design.

It is also important to factor in the cost of any tools that may be needed for the project.

By taking into account the design and size, materials, and cost of the project, you can be sure to build a catamaran boat that meets your needs and budget.

With the right amount of patience and attention to detail, you can build your own catamaran boat in no time.

Gathering Materials

diy catamaran hulls

Gathering the materials needed to build a catamaran boat from scratch can be a daunting task, but it is essential for creating a sturdy and safe vessel.

Before starting the building process, it is important to have an accurate and detailed plan for the boats design and size.

Once a plan is in place, it is time to begin sourcing the necessary materials.

The most common materials used to construct a catamaran boat are wood, fiberglass, and epoxy.

When choosing wood, it is best to select a species of timber that is strong and durable, such as mahogany, teak, or cedar.

Additionally, the wood should be clear and free of knots, splits, and other defects.

Fiberglass is a lightweight fabric that is resistant to water and provides additional strength to the boats hull.

Epoxy is a waterproof adhesive that is used to seal the boat and ensure that it is watertight.

It is important to ensure that the materials are of high quality, as this will help to ensure the boats longevity.

Additionally, it is important to purchase the necessary materials in the correct amount and size.

Too little or too much of a material can be a costly and time-consuming mistake.

Finally, it is important to keep any leftover materials for future repairs or modifications.

With the right materials gathered, the next step is to cut the wood and begin the assembly process.

Cutting & Assembly

Cutting and assembly are the most important steps when it comes to building a catamaran boat from scratch.

The first step is to decide the design and size of the boat.

This will determine the type of materials you need to gather and the amount of effort that needs to be put into the project.

After deciding on the design and size, you will need to cut the wood to fit the design.

This includes cutting the wood to the desired size, as well as cutting any additional pieces that may be needed to complete the design.

It is important to ensure that all the pieces fit together correctly and securely, as any mistakes could lead to a weak boat.

Once the wood has been cut, it is time to assemble the pieces together.

This involves attaching the pieces together with glue, screws, and nails, and ensuring that the pieces fit together securely.

It is important to be careful and patient when assembling the pieces, as any mistakes could result in a weak and unstable boat.

Once the frame is ready, it is time to lay the fiberglass, and apply the epoxy to seal the boat.

This is an important step, as it will make sure that the boat is waterproof and durable.

Finally, you can add the finishing touches, such as the hardware, paint, and rigging.

With the right amount of patience and attention to detail, you can have your own custom catamaran boat in no time.

Laying Fiberglass & Applying Epoxy

diy catamaran hulls

When laying the fiberglass and applying epoxy, it is important to take your time and be precise.

Fiberglass and epoxy are key components of a catamaran boat, as they provide the strength and waterproofing necessary to keep the boat afloat.

Start by laying the fiberglass over the frame of the boat.

Make sure to cut the fiberglass to size and overlap the edges for a strong seal.

Once the fiberglass is in place, mix the epoxy and begin to apply it.

It is important to apply the epoxy in a thin, even layer to ensure a proper seal.

Make sure to move the epoxy around to get it into all the nooks and crannies of the boat.

Allow the epoxy to cure and then you can begin to add the finishing touches.

Finishing Touches

Once the frame of the catamaran boat is built, it is time to add the finishing touches.

This includes adding the necessary hardware, painting, and rigging the boat.

Hardware: Before adding the hardware, it is important to ensure that the frame is stable and secure.

Add the appropriate hinges, screws, and nails to the frame.

Make sure that the screws and nails are the correct size and do not exceed the recommended load capacity of the frame.

Painting: Once the hardware is added, it is time to paint the boat.

Choose a paint that is suitable for the materials used in the construction.

Make sure that the paint is applied evenly and that the frame is completely dry before applying the next coat.

Rigging: The last step is to rig the boat.

This involves attaching the sails, running rigging, and standing rigging to the masts and booms.

Make sure that the rigging is properly tensioned and secured.

Once all of these steps are complete, your catamaran boat is ready to sail.

Hardware & Paint

diy catamaran hulls

The last step in building a catamaran boat is to add the hardware and paint.

This step is often the most rewarding, as it is the finishing touch.

Depending on the design of your boat, there are various types of hardware you may need.

Some of the most common items are cleats, winches, fasteners, and decking.

After selecting the required hardware, you will need to install them on the boat.

It is important to use the correct type of screws and bolts, and to secure them tightly.

Once the hardware is installed, it is time to apply the paint.

The type of paint and color you choose will depend on the design of your boat.

It is important to use a high-quality marine grade paint that is designed to handle the extreme environment of the ocean.

If you are up to the challenge, you can add some custom artwork or detail to your catamaran boat.

Adding the hardware and paint is the final step in building a catamaran boat.

With patience and attention to detail, you can create a beautiful and unique boat that will last for many years.

Be sure to take your time and enjoy the process of constructing your own boat.

Once you have finished the frame, fiberglass, and epoxy of your catamaran boat, you will need to move onto the rigging.

This is a crucial step in the construction process, as it will keep your boat safe and secure on the water.

When rigging a catamaran, there are a few key components that must be taken into account.

First, you will need to determine the type of rigging you will be using.

Typically, catamarans use a combination of standing and running rigging.

Standing rigging consists of cables and lines that stay in a fixed position to provide stability and strength to the boat, while running rigging consists of lines that are used to adjust the sail and mainsheet.

Additionally, you will need to choose the right type of rope and hardware for your rigging setup.

The rope should be strong and durable, and the hardware should be made of stainless steel and be corrosion-resistant.

Once you have chosen the type of rigging and hardware, you can start assembling the rigging lines.

This process involves carefully measuring and cutting the lines to the proper lengths, and then attaching them to the mast and boom.

Depending on the type of rigging setup, you may also need to attach the lines to the hulls and deck.

It is important to inspect the rigging lines and hardware regularly to ensure that everything is secure and in proper working order.

Rigging a catamaran boat can seem like a daunting task, but it is essential for the safety and comfort of your vessel.

With the right tools, materials, and attention to detail, you can successfully and safely rig your catamaran boat.

Final Thoughts

Building a catamaran boat is a rewarding experience that requires patience and attention to detail.

With the right plan, materials, and steps, you can build your own boat in no time.

Now that you know the basics of how to build a catamaran boat, why not grab your tools and get started on your very own project? With the right motivation and dedication, you can make your dream of owning a catamaran boat a reality.

James Frami

At the age of 15, he and four other friends from his neighborhood constructed their first boat. He has been sailing for almost 30 years and has a wealth of knowledge that he wants to share with others.

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BUILD YOUR RAKU CAT WITH A DuFLEX KIT BY FOLLOWING THESE NINE BASIC STEPS

Duflex Kit Construction Step.1

Step 1. Kit Design

Work with us to finalise the details of the design you have chosen including any design options or additional modules to be included in the kit.

We will determine the laminates, the number of panels required for each laminate, create the cutting files and prepare a quote for the kit if it is not already priced.

Once the design details and pricing are confirmed you are ready to place your order.

Duflex kit construction Kit image-01

Step 2. Unpacking

2. The kit arrives at your workshop door, usually by container, as a stack of 1.2m x 2.4m routed composite panels ready to be joined. The shipment will normally include additional reinforcements, resins, and ancilary products as specified.

Unpack the shipment and stack the panels out of the way of the space where the panels will be joined.

If you have purchased a joined kit many of the panels will already be joined up to the length that can be shipped in a container (12m).

Duflex Kit Construction Step 2 image-02

Step 3 Joining the Panels

Set up the work space where the panels are to be joined.

The panels have a scarf join called a Z join that facilitate the join without needing tapes.

The joining can be done with a heated Z press that cures the epoxy join quickly. Alternatively they can be joined with clamping pressure.

If the panel are are being joined with the Z press you will need an elevated work bench the full length of the longest panels you are using. (image below).

If you are joining them with a clamping technique the space can be on the factory floor.

A nesting booklet is provided with the kit to show how the panels are joined (right)

Duflex kit construction Step 3 image-01

Joining the panels with  clamping pressure

diy catamaran hulls

Panels are being joined into a single long panel by painting the surfaces of the scarf join with epoxy screwing through plywood battens that have a release film applied to one side.

Joining the panels with the Z Press

diy catamaran hulls

Step 4 Stacking Joined Panels

Once the joins are cured the panels are stacked to one side until they are needed for the job. The inividual parts should not be cut free of the panels until they are required.

Bulkhead and floor panels will be needed before the hull sides and cabin top so they should be left to the front of the stack wherever possible.

Diuflex Kit Construction Header image step 5.

Step 5. Separating the Parts

When assembly is ready to begin the individual parts are separated from the panels by cutting the joining tabs. It is likely you will be building onto moulded hull bottoms that have been built from strip planking or another method of building moulded components. The process for building moulded components is described in another article.

Duflex kit Construction Step 5 Image-01

Step 6. ASSEMBLY

As the joined panels are assembled onto the job you will need to apply glass tapes to the joins as specified in your plans.

Panels can be surfaced and coated inside and out with high build while they are on the workshop floor to minimise fairing time once they are assembled to the boat. The paint on the panels shown here has been kept back from the edges to provide a good bond for the tapes.

Duflex Kit Construction Assembly image-01

Smaller items such as steps, seats and dagger cases are nested into the kit and for the more complex parts diagrams are provided to assist with the assembly process.

Duflex Kit Construction Header Image Step 7

Step 7. Interior

Interior kits can be ordered with the primary kit, or they can be ordered later when final decisions have been made about the interior arrangement.

A compromise solution is to order the interior as a set of plain planels that can be cut to shape on site after finalising the layout.

Duflex Kit Construction Step 7 Image 2

Step 8 Fairing, Painting, Hardware Installation

8. The DuFLEX construction process goes a long way to minising the amount of fairing that has to be done, but inevitably any boat that has not come out of a female mould will require some level of fairing and surface preparation prior to painting. 

The fillers and resin systems required for the fairing work are normally supplied as part of the kit.

Hardware installation is the same as for any other form of construction using high density core inserts or consolidated laminate in way of fittings.

Duflex Kit Construction Step 8 Image 2

Step 9. Sailing

Go Sailing. This Barefoot 40 Catamaran was built entirely with a Duflex kit in Foam/Glass and Epoxy resin systems from ATL Composites

diy catamaran hulls

DuFLEX Kits are manufactured and supplied world wide by ATL Composites

atlcomposites.com.au

And in Europe by VDL Composites

www.vonderlinden.de/her/28/vdL-Composites-GmbH

For more information on DuFLEX and associated Products 

atlcomposites.com.au/category/27/DuFLEX

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Do-It-Yourself: Build your own A Class catamaran!

Added by damonAdmin on Apr 23, 2003 - 12:26 AM

Ever thought about building your own catamaran? Here's an illustrated guide to one sailors project building a beautiful A-Class catamaran out of plywood. A big thank you to the builder, Chris Williams, for letting me share his work with the rest of the beachcat sailors.

A skill, known in boat building as lofting, the skins which will make the hull are cut out of the lengths of plywood. The front and rear bulkheads are also cut out along width the center board cases

 

A jig must be constucted to conform the hull to shape. The jig is a large 20ft long table with many structural members to give it strength against the pressure of the hull skins. The hole in the jig is shaped to the final shape of the top of the hull.

A setup involving laminated spruce blocks glued to the sides, gunwhales and bulkheads serves as an anchoring point for the crossbeams.

The foam spacers are glued in place with epoxy with filler added.

Epoxy on decks using staples and packing strips for pressure.

Route and Plane off excess.

Cut centerboard slots, fiberglass front gunwhale.

Use ridiculous amount of filler (don't breath the stuff), epoxy, and sanding to get dynamite finish

Saturate boat with 3 coats epoxy.

.
  • Jul 25, 2012 - 06:16 AM
  • Dec 11, 2012 - 03:35 PM
  • Apr 19, 2013 - 06:52 AM
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  • Aug 14, 2016 - 01:47 PM
  • Sep 27, 2016 - 07:26 AM

More articles in category Do-It-Yourself & General Stories

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  • Dutch Youth Champions Aim for Olympics (by damonAdmin on May 12, 2007)

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Building a sailing catamaran.

A collection of sailing catamaran building logs, from choosing sailboat plans to yacht launch...join us on our journey

This 'glass-over-ply' sailboat is proof that a DIY'er can successfully build an ocean-going multihull cost effectivly.

Having reliable Boatbuilding Resource Books , WILL HELP fast track your decisions prior to, during and post building.

We also wanted a light sailing catamaran that we could beach with ease. This now allows us to save money on one of the biggest maintenance DIY chores, sailboat antifouling without having the costly expense of slipway fees.

Where do I start?

Plywood and Epoxy Catamaran Why both? 

pure majek catamaran

Plywood construction is the cheapest building method available and very forgiving while one hones their skills.

Finishing with a solid fiberglass outer is also a task made easier, given the amount of glassing and gluing needed during such a project. Doesn't make sense? Read more...

Talk to the sailboat designers , get to know their design types. Get on Forums and ask the 'dumb' questions. Go to marinas (not boat shows) and look for home-build yachts.

how to build a boat

"It takes a strong desire and a will to achieve. Building a large catamaran is certainly achievable". "If you want a yacht with all 'bells and whistles', keep working because it costs money...a lot of money". J Coomer

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many sailboat plans to choose from!

Is it cheaper to build or buy? There are many yacht plans to choose from, but dont kid yourself. Many have tried to do it on the cheap and their result shows. If there was a cheaper way, the sailboat designers would tell you. Afterall, they would use that reason to sell there plans!

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DIY boat projects on Pure Majek from new navigation equipment, anchoring systems, rewiring yacht electronics diagrams, AIS and much more.  Its been ten great years since launch and we look at things that have worked and those we would change. Join us and be inspired.

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goal setting, planning and building

Setting achievable goals and how to stick to them. From the planning process, what and why we did many things, importantly, things we would do differently. The following pages draw on these experiences described in far more detail in our book ' A Sailing Catamaran Building Adventure '

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‘Green power’ is climbing up the priority ladder to such an extent nowadays that some predictions of fossil fuel costs (scorned at a few years ago), are coming home to roost.

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There are a few tricks here to with respiration, thinning of the topcoat, temperature and coat thickness. All achievable by setting goals and being disciplined .

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Building catamaran Pure Majek videos

Just want videos?  Click our Youtube Channel . Over 500,000 views and counting. NO TALK videos . Thank you for your support.

Catamaran Hulls

Click photo

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Catamaran Fitout

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Catamaran Internal Painting

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Bridgedeck & Turret

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External Painting

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Final Fitout

sailboat internal fitout

Antifoul & Decktred

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Fitout, ready for launch

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Starting out

Internal Painting

Bridgedeck and Turret

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Time For a Catamaran Adventure

Isn't Time For Yours?

Building Your Own Catamaran

Building your own catamaran is another option to getting into your own boat. In this page we will go over the advantages, considerations, and a detailed history and journal of our boat-building adventure with Light Wave . We hope this will give you a clear picture of what lies ahead if you go this route, including:

  • Construction methods
  • 9 essential design features
  • Review of the four leading catamaran designers for home builders
  • Construction times
  • Budget: How much did it cost to build a basic cruising catamaran?
  • Layout of our catamaran, LightWave , and lots of pictures
  • Carllie’s article from September 2000 Multihulls Magazine: “The Boat Builder’s Wife “
  • Equipment outfitting
  • Radio and communication outfitting
  • Dinghy selection and considerations
  • Having a boat custom-built for you

Because of the huge dollars needed to buy a new or even a used catamaran, we would never have gotten a catamaran if we hadn’t built it ourselves.

Let’s start by saying that building any type of larger boat, especially a catamaran, can be one of the most intellectually and physically challenging things you will ever do.

It has been said that building a large boat is the closest a man can come to giving birth to a baby. In other words there is going to some discomfort and pain along the way; you will question yourself on whether this was such a good idea; it’s very difficult to reverse the decision; and though friends will support you, you will be on your own most of the time with your significant other if he/she is game.

Know your boat

You will intimately know every part of your boat. You will know where every wire, hose, bolt, bulkhead, rib, and support is because you installed them!

Pride of ownership

We have often thought what it would be like to just buy a boat from a manufacturer, and know that while owners who have spent a lot of cash (or future life to pay off the lien) their often possessive and competing-with-the Joneses could not begin to compare to our quiet glow of happiness and akinship we feel with Light Wave .

Our boat is like part of the family. So much time was spent on her that we have a major emotional investment. Every time we see our vessel – from a distance at anchor or approaching her in our marina, we say, “What a pretty boat! I can’t believe we built it!” Then that sense of accomplishment settles back in and we feel we have indeed earned the privilege of all of the beautiful experiences we have had sailing, cruising, exploring the beautiful BC Coast and much further a field (or should we say “an ocean”?).

You will be able to pay for the materials as you go and “donate” your time to the cause.

Get a newer design

Many of the production boats that are out there are designs of many years ago because the manufactures have to recoup their capital investment on the mold and production setup. When you build your own you have much newer designs to draw from.

Details on Our Boat Building Adventure

We had sailed our first boat Wave Dancer for five years and had many adventures on the British Columbia coast. In May 1996, I had just returned from a little one-week solo trip in the Gulf Islands of BC when I bought the book, The Cruising Multihull by Chris White (Future link to book review on our web site).

This is the book that got me going (Carllie was not yet convinced). I must have read it a half dozen times over the next 6 months, each time becoming more convinced that this was the way to go for our next boat. It was really still pre-internet web site days so I wrote to all the designers that were listed in the back of the book. Over the next several weeks packages of information started appearing in the mailbox (there is just something about getting packages in the mail – I guess it’s the anticipation). I would pour over these preliminary printed pages with pictures and accommodation layouts. Next, I put a few dollars down to buy the information packages and study plans from the top prospects.

I waited patiently for the study plans. It was like the night before Christmas when I was kid. Oooh the wait! Finally they came, and again I carefully scrutinized the next level of detail. Things were getting a little more serious. The top contenders were:

  • Richard Woods
  • Chris White
  • James Wharram

Click here to read my comments and reviews on their catamaran designs as well as those of Jeff Schionning.

I remember initially drooling over the Atlantic 42 by Chris White, still one of my favorite designs. It seemed to be so seaworthy (by the way if I run into about $800,000 USD any time soon, I am going to buy an Atlantic 55). The most important piece of advice that came out of the material was from Richard Woods:

“Build the smallest boat you‘d be happy with it.”
Axiom #1: The hours to build a catamaran is in almost in direct proportion to its weight.

Which brings us to Axiom #2:

Axiom #2: It takes about 1 hour to create 1 pound of finished boat.

In our case we spent 3,500 hours ( click here for full details on the construction hours ) to build a 4,000 lb. boat (just a little less than 0.9 hours per pound). If a boat’s empty weight is 8,000 lbs., it will probably take about 6,000 hours to build.

When you think about it, you can only mix and handle so much material per hour. More boat weight, more material, more hours. Sure there are some economies of scale on a bigger boat, but usually the systems become more complex and these take longer to install.

This decision process took 8 months and I figured we’d launch in 6 months. It was now January of 1997. Little did we know it would be 26 months and 3,500 hours between the two of us until we launched on June 5, 1999. We ordered the full plans and we were off and running.

We were ready to build, but where would we start the process? First of all, we live in a tiny 480 sq. ft. apartment in Vancouver. Back-yard building wasn’t exactly an option so I found a small garage nearby that we rented for 5 months.

After about 4 months in the garage, I had made all the small parts and it was time to build the hulls. This meant that we had to go larger facilities. We found space at Shelter Island Marina and Boatyard in Richmond. This is the biggest boat yard in the Vancouver area with dozens of commercial and private projects, big and small, under way.

We were out of money by then, so we sold our first boat so we could buy resin and fiberglass. It was a traumatic time as we said goodbye to our beloved Wave Dancer . We were now committed. We than had all the foam for the hull cores, barrels of resin, and huge rolls of matting and roving needed for the fiberglass skins delivered to our “domed stadium”. We kicked ourselves many times that we didn’t take a picture of this raw material stacked in one corner of the empty shed, so we could later show “before” and “after” photos. It was time to build the hulls.

Over the next several months we proceed to join the hulls with the beams I had built in the garage, and then to install the cuddy cabin, cockpit, and decks. By the spring of 1998, it was staring to look like a catamaran. Through the spring and summer of 1998, we continued with the major structural components: mini-keels, hatches, stairs, and interior. Then we went on to the very laborious work of fairing the boat before painting. Don’t under estimate that job!

By October 1998 we were ready to prime the boat and start painting. I really thought this would go quickly. I forgot that I would have to do two more complete sandings to sand off and finish the two layers of primer application. In addition we had to fill countless pinholes – a laborious process somewhat like hiking up a mountain – each time you get to what you think is the top, you see another summit!

The boat seemed to get bigger and bigger. Believe me, there is a lot of surface area on a catamaran. I clearly remember that last sanding: I had reached the end of my physical and mental endurance – I was exhausted. I was ready to move on to the next phase – any phase but more sanding!

We now started spray-painting the hulls bright yellow. It was around this time we decided on our boat name of Light Wave . The painting took over a month: the hulls being the easy part, it was the topsides, the nonskid, and all the masking and prep that seemed to take forever. Happily, the worst of the dust was gone.

By March 1999 we were in the home stretch. The center bridge deck cabin was completed so we took a week off from our paid jobs and lived on the boat in the shed so we could work all day and not waste time commuting. March, April and May were frantic months as we finished all the final touches: engine installation, rudders, windows, deck fittings, electrical, plumbing, mast, and rigging. See our outfitting page (for more details on what we picked and why, and things we would do differently now.

Initially, our electronic systems were relatively basic but included GPS and autopilot see the following link for all our electronic outfitting choices and reasoning for more details.

It was May 22, 1999 and we decided that Saturday, June 5th would be “Launch Day” so we could send invitations to all of our friends. On the Friday night before Launch Day, we still had a number of final things to do, many of them outside. Unfortunately it was pouring rain. We were tired and very wet but the boat had to go into the water next day so we persevered on till everything was ready.

The moment of truth came as Light Wave was lowered into the water. While still in the slings of the Travelift, I jumped aboard to check for leaks. Of course there weren’t any! More food and laughs and tours of the boat for all attending. It was a great day.

Emotionally drained that night, we slept in Light Wave in the water for the first time. It was another week before we actually went out for our first trip as we had to sell the shed, setup sails, and install some final deck hardware.

To sum it up, building a catamaran was a great experience. We learned a lot. Carllie and I grew closer together through it all. We had a great time doing it. We had a beautiful catamaran to show for it. Now it was time for a catamaran adventure !


diy catamaran hulls

How To Create the Perfect Cruising Catamaran Layout

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More than ever before, sailing fans are gaining an interest in catamaran layouts and designs that define performance. Many others are also looking into either buying a cruising catamaran or designing and building one. While building a catamaran is no piece of cake, this article shows you how to create the perfect cruising catamaran layout. 

To create the perfect catamaran layout, carefully consider factors like a good hull design, optimal helm station placement, boat stability, and adequate load-carrying capacity. Excellent galley positioning, ease of handling, and spacious living and sleeping quarters are also crucial. 

The modern cruising catamaran is a far cry from the simple Polynesian double canoe of old. That’s because structural innovations and new composite materials have resulted in multihulls with impressive cruising abilities. Keep reading to learn more about exceptional catamaran layouts.  

The Changing Trends in Catamaran Designs

The early cruising catamaran designs resulted in boats that could sail much faster than traditional sailing boats. In addition, they could glide with ease in shallow waters and required less wind and crew. Unfortunately, these cruising cats were heavy, had small, cramped interiors, and boasted somewhat challenging handling abilities. 

Today’s cruising catamarans are different. They boast the utmost comfort, high speeds, and the safety of a well-designed cruising yacht. They are also more exciting, visually appealing, deliver the smoothest of rides, and sport more spacious interiors. 

Have a look at the below video showcasing the top ten cruising catamarans:

Features To Look Out for in Catamaran Design Layouts

Cruising catamaran designers understand what most sailors look for in a cruising vessel. They, therefore, design cruising multihulls that address these pertinent issues and more. Some of the features you might want to consider having in your dream boat include the following:

  • Responsive performance. Outstanding performance allows for pleasurable cruising and ensures your safety since you have more options during difficult weather.
  • Excellent load-carrying ability . This allows you to have an extended cruising vacation or ocean crossing.
  • Boat stability . Go for lightweight, robust construction, which results in a lot of buoyancy.
  • A low center of gravity for smooth rides and enhanced performance. Centering weight around a low center of gravity improves the overall sailing quality, reduces pitching movement and reduces the risk of capsizing .
  • Adequate bridgedeck clearance to reduce slamming and provide better performance in rough conditions. A high bridgedeck also means less noise and slapping action from the waves hitting the boat bottom, thus ensuring a quieter, smoother ride.
  • Comfortable sailing. To enjoy a quality life on board, you need comfort while at sea. Thus, elements like gentle movement, no creaks or groans, no bridgedeck slamming, and minimal pitching are essential for quality, peaceful and restful sleep.  

Now that you know what a cutting-edge catamaran features, let’s look at how to create the perfect cruising catamaran layout.  

Build a Larger-Sized Catamaran

The early catamarans ranged between 36-42 feet (10.9-12.8m). At the time, this appeared to be a good size in terms of safety and ease of handling. However, the boats were heavy, and the additional drag and displacement adversely affected their performance and windward ability. 

It’s now possible to make the new generation catamarans lighter, larger, and more spacious with excellent power-to-weight features. The current trend is larger-sized catamarans in the 45-50 feet (13.7- 15.2) range. Composite engineering and technologically advanced equipment such as furling systems, electric winches, and autopilot make it easier for a smaller crew to sail larger boats with confidence. And to do so without compromising safety or stability. 

Get the Best Catamaran Hull Design

A cruising catamaran’s performance depends on three main aspects; its length, the sail area, and the boat’s weight. Long boats are generally fast. A light boat with more sail area is also faster than a heavier boat with less sail area. In other words, you can make a multihull faster by making it longer, lighter, or adding more sail.

However, there are exceptions to this rule; a boat with too much sail area is more likely to capsize if there are brisk winds. Also, if the boat’s design makes it too light, it’ll be unable to handle much punishment, while a hull design that’s too slim would make the vessel incapable of carrying any significant loads. But that’s not all; if the boat is too long or too large, it’ll become grossly exorbitant. Narrow hull shape might also mean smaller cabins.

Nonetheless, these three factors alone are not enough to determine a cruising catamaran’s performance. While faster boats boast finer hulls, the wetted surface area tends to increase as fineness increases; thus, fine hulls end up becoming less fast in low wind speeds. Also, very wide hulls mean a reduction in actual performance.

The Prismatic Coefficient (Cp), a measure of how full the ends of the hull get, is the most essential design hull shape factor for any catamaran. A high Cp equals high speeds, although you can still use a lower Cp if you have fine hulls. Nevertheless, the key to a good Catamaran design is a higher Cp for fast sailing. 

To achieve a high Cp, there are several things you can do: 

  • Fit bulb bows . Unfortunately, the bulb bows tend to slam in a seaway when you do this.
  • Have an extensive planning aft section . However, this can increase the wetted surface area, WSA and lead to additional challenges. 
  • Flatten out the hull rocker and add a bustle aft. This helps to add displacement aft. 

diy catamaran hulls

Build Convertible Main Living Spaces

The open cockpit is now a thing of the past. Instead, pioneering designers for catamaran manufacturers like Nautitech, Gunboat, and Catana now replace traditional-style salons, cockpits, and cabins with spacious indoor and outdoor living spaces. The concept involves merging separate saloon and cockpit areas with duplicate lounge spaces and the use of hard-wearing composite materials. 

You can also design the cabin to suit your preferences. You may decide to add a cabin or remove one, add a bathroom, have the forward berth in the hull or on the wing deck.

  • The design enhancements boost usable space while opening up the living areas.
  • It reduces time and costs for interior maintenance and cleaning. 
  • Large windows bring in more light, increasing visibility. 
  • Luxurious, spacious, and airy owners’ cabins provide more comfortable living space. 

diy catamaran hulls

Bulkhead Helm Stations vs. Twin Stern Steering

Many catamaran owners have traditionally preferred bulkhead steering. This helm position remains popular, but twin stern steering positions come with more advantages since they provide greater sails visibility. The twin stern positions are also best suited for racing or day sailing since they often lack adequate protection for extended cruising. 

Exposed helms are not ideal for a long ocean passage. Go for a safe, secure, and well-protected helm station that provides good visibility and comfortable space for long watches. Again, it’s best to have all control lines at the helm to establish a static control station. Also, have all push-button-controlled winches, instruments, windlass, and autopilot prominently located inside the cockpit. 

  • Twin stern steering positions give you a better view of the sails
  • You get a better feel for overall sailing conditions.
  • Twin stern steering positions lack the necessary protection for extended cruising. 

diy catamaran hulls

Go for the Flybridge Design

The flybridge design is appealing because it offers excellent visibility, more comfort, and additional entertainment and lounging space for everyone on board. Unfortunately for smaller boats – those below 50 feet (15.24m), there is minimal protection from the elements. As such, you might want to consider adding enclosures to offer protection. The flybridge, thus the helm, remains cut off from the vessel, which makes communicating with the crew a challenge. 

  • It provides great visibility.
  • It offers comfortable spacing. 
  • It might be unsafe to move from the cockpit to the flybridge in bad weather.
  • It isn’t easy to communicate with the crew.

Daggerboards vs. Fixed Keels

Average cruising catamarans typically utilize fixed keels while high-performance cats have daggerboards . Fixed keels allow you to beach your catamaran easily, and your hull remains intact if a collision occurs. While you lose some angle when sailing upwind, you gain more interior space in the hulls that you can put to good use.

Daggerboards are essential in a performance cruising catamaran since they guarantee that the boat delivers good upwind sailing, including during difficult situations. During long passages, they allow you to point better upwind though the drawback is that they consume much interior space within the cruising catamaran’s hulls.

Since flying on foils ( hydrofoils ) isn’t that practical on cruising catamarans, designers of larger-sized boats have also come up with modified daggerboards. These daggerboards produce lift and prevent leeway, too, thereby improving performance significantly, as seen with the Catana 59’s curved daggerboards. These foil-like daggerboards lift the boat ever so slightly upon reaching higher speeds, making it feel less heavy and much faster. 

At the end of the day, calculating the performance of a boat sailing in a wide range of varying seas and winds might not be easy – despite a daggerboard or fixed keel configuration. This is because upwind speed depends not only on the sails’ quality but also windage and the height of the bridgedeck beyond the water.

  • The design innovations -curved daggerboards and hydrofoils- improve catamaran performance significantly.
  • Daggerboards enable you to access otherwise inaccessible anchorages.
  • Daggerboards take up hull space in the hulls of your vessel.

diy catamaran hulls

Galley Up vs. Galley Down

Galley layout are becoming more and more important as more people, including families, start sailing regularly. While at sea, your galley needs to be a safe place, well-ventilated, and functional. Everything should be well-thought-out for the sailor’s comfort, including handholds to make it safer to move around the boat. 

While the galley location can either be up the bridgedeck or down in the hull, galley up appears to be the most popular trend. This makes the galley the focal point of both the living space and entertainment areas.

If you have a family, this placement is ideal since you make your meals from the galley and get to spend most of your time here. Many cruising families and couples prefer this arrangement and find separating the galley down the hull unappealing. Besides, carrying hot food up and down the staircase is unsafe.

Still, galley down is ideal for charter boats since it offers a private cooking area and uses up hull space efficiently.  

  • Having the galley on the bridgedeck is ideal for families and cruising couples.
  • Placing the galley on a similar level with the serving area and cockpit is safer and less tiring.
  • There’s better ventilation on the bridgedeck, making for comfortable cooking. 
  • There’s less kitchen privacy galley up.
  • On smaller catamarans, this layout can impact the size of the saloon seating area significantly.

Production Catamaran vs. Custom

The choice of either a production catamaran or a custom design might seem pretty straightforward. Production catamarans from major brands come backed by proven designs, dependable construction, solid warranties, and many years of experience. The catamarans are easy to service, source for parts, and most – particularly the owner’s versions – hold on to their value, making them much easier to resell. 

On their part, custom boats are fantastic in that you can tailor them to your exact needs. However, they might be more challenging to maintain or service. That’s because of parts unavailability and lack of construction knowledge.

Choose Quality Construction Materials

The best quality materials to use on your catamaran are both light and robust. While carbon fiber is great, plywood, plywood/epoxy, and strip-cedar are excellent materials too. What’s more, they are also affordable, so you don’t have to get too hung up on cutting-edge building materials. What matters is build quality; thus, a well-built plywood catamaran boat can last as long as a boat made from more high-tech materials. 

Combining various materials also helps combat some of the issues that plague plywood boats in terms of resale value. At times, the design tends to make the boats appear pretty dated.  

  • Plywood and strip-cedar materials are affordable and provide excellent build quality. 
  • Plywood boats may have a lower resale value than those built with modern materials.

Consider Ease of Handling

An important factor in handling a cruising catamaran is deck layout. Most cruising catamarans sailed short-handed , so if your boat has one helm, all lines should run back here to allow for a static control station for the entire boat. 

The other essential element is visibility from the helm. The 360 degrees of visibility while maneuvering, docking, or underway is crucial to your boat’s safety, as well as life and property. As such, you should be able to view both bows, or at least the pulpits and sterns, while standing at the helm. If not, you may have challenges handling the boat due to blind spots.

diy catamaran hulls

Consider the Load Carrying Capacity

A well-designed catamaran is enjoyable to sail in all weather conditions. It’s also much easier to handle than a monohull because of its widely spaced twin engines. But when you immerse extra hull depth, the vessel gets sluggish and moves slower, maneuvering in tight spots or when docking becomes more challenging. Furthermore, the hull submersion reduces bridge deck clearance, leading to hull slamming. 

To allow for adequate load carrying capacity, you need a design that provides a generous displacement. This helps to ensure that you maintain reasonable bridge deck clearance even when fully loaded. It also allows you to avoid digging big holes in the water as you drag your transoms. 

Displacement refers to the amount of buoyancy designed into the hulls, which essentially means that your boat will cruise better if its weight is less than your designed displacement.

Note that an overloaded catamaran not only loses out on performance but eventually, on safety too. To counter this, choose a lightweight catamaran with hulls bearing cored construction and interiors made of lightweight materials.  

Remember, when you go cruising, you will need to carry fuel, extra water, supplies, equipment, and amenities, translating into thousands of extra pounds. Therefore, try and avoid the following design errors to ensure that your catamaran has an adequate load-carrying capacity:

  • Avoid putting in place too much accommodation space.
  • Avoid building a heavy boat ‐ use low-tech construction materials.
  • Avoid installing inboards in a small boat.
  • Lightly constructed catamarans perform faster and carry more weight.
  • Cored construction makes for a strong and stiff catamaran, thus enabling good performance.

Final Thoughts

A well-designed cruising catamaran is a joy to behold. Today’s modern technological advancements mean that you can buy or build a light but strong cruising catamaran. And as you can see from this article, there are many excellent cruising catamaran layouts that you can choose from. 

However, whichever layout you decide on needs to fit your sailing needs and purposes to ensure you remain comfortable and safe while at sea. Above all, ensure that you go for a vessel that you can handle with ease in all weather conditions.

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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Catamaran Hull Design

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

diy catamaran hulls

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

Rick

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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Catamaran & Small Boat Building

to my website. Here you’ll find photos, stories and information on building boats large and small, with tips and tricks I’ve picked up along the way. I built this website originally to accompany my YouTube channel . The blog section has information on various topics.

diy catamaran hulls

A 12m cruiser/racer catamaran – 2 yrs & 9 mths to build – launched 15th August 1997. Details of the build.

diy catamaran hulls

Small boats

Small boats you can build in your garage.  A good family project and a way to get a taste of boat building. See how they were built.

diy catamaran hulls

Plans to build your own boat. Packed with information for the first time builder. Start building your boat now.

Where to start

Building your own boat and sailing off over the horizon, is a dream that lives inside many. Well at least that’s the impression I get from the many people I met while building Tokyo Express (TE) and the feedback now f rom the videos on YouTube.  After years of dreaming, at 39 years of age I finally turned that dream into reality with the launching of Tokyo Express. This website is about my journey.

You don’t need expensive kits

or exotic materials to build a boat. You don’t need expensive tools or a degree in engineering either. I fabricated most of the parts and systems on Tokyo Express (TE) from scratch. Steering system, steering wheel, doors, hatches, fore beam, catwalk, daggerboard, rudders, engine mounting, generator, electrical system and plumbing.

Even the mast I bought as a kit. I had more time than money so I built everything I could. There were no exotic materials used and yet I ended up with a robust, lightweight and extremely competitive boat that was lighter than a typical production boat.

If I hadn’t been designing and redesigning many parts of the boat, learning for the first time how to do things and building a shed, the boat would have been finished a lot quicker.

On the Tokyo Express page

page you will find an overview of the steps I took building TE. If you are thinking of starting a similar project, this is a good place to start. It was a lot of work, but it was also the most rewarding project I have undertaken. It was well worth the sweat and tears. Please look around. Email me if you have questions…

Recent Posts

Catamaran vs Monohull

  • Catamaran vs Monohull

by Tim Weston | Mar 11, 2019 | Building , Cruising

Catamaran vs Monohull If you are thinking of building or buying a yacht, you have a significant choice to make, before you even start looking at individual boats. Do you want one hull or two? Deciding between a catamaran and a monohull is a big decision and one worth...

Going fast – in small boats – hull speed.

  • Going fast – in small boats – hull speed.

by Tim Weston | Sep 30, 2018 | Building , Plans

Going fast - in small boats (with a small motor) This article looks at how to go fast, in a boat with a small motor. Plodding along at snail’s pace can get a little boring. No matter how relaxed I am and how much time I have nothing puts a smile on my face quicker...

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DIY Styrofoam Catamaran

license

Introduction: DIY Styrofoam Catamaran

DIY Styrofoam Catamaran

This is a Styrofoam catamaran i built. I had been wanting to build this for a while, then in the last few days of summer i decided to build it. This only took 2 full days to build and one day to test. The catamaran costed me around 200 dollars (sail not included) and this is comparable to a store bought catamaran which would cost 2000 dollars

In this instructable i have included a few schematics (located on the last page) , a materials list, and various pictures and descriptions for all steps.

If you plan to build this project i suggest you check out the video and if you like this project be sure to check out my channel or my website for more projects like this.

Step 1: Materials

Materials

The materials i needed for this project were:

2"x4"x8' pieces of wood - 2

2"x3"x8' pieces of wood - 1

2"x2"x8'pieces of wood - 6

1”x2’x8’ Styrofoam sheet - 5

1.5”x14”x4’ Styrofoam sheet - 5

½’’x2’x4’ piece of plywood - 2

½’’x4’x6’ piece of plywood - 1

Sail and mast - 1

Epoxy (dollar store epoxy is cheapest and works well) - 7

Step 2: Assembling a Pontoon

Assembling a Pontoon

The catamaran will be composed of 2 pontoons. These pontoons will have a frame filled with the white, less durable Styrofoam in the center; then we will later add the pink Styrofoam to the outside.

To start off i lay out two 2x2 pieces of wood with the white Styrofoam pieces in the center. This will be the inside of the pontoon. Next i add a front triangle onto the pontoon. As you can see in the third picture i added 2 struts near either end of the pontoon. Once that is finished i fill the pontoon with white Styrofoam and cut it to fit in the gaps.

Step 3: Finishing the Pontoon

Finishing the Pontoon

to finish off the pontoons we must first cut 4 pieces of Styrofoam to size (2 for each pontoon). To cut them all at once i clam them together and use a reciprocating saw to cut the height from 2 feet to 17 inches (the height of the pontoon).

After that i use 1 - 1.5 tubes of epoxy as adhesive. I spread the epoxy on the wooden frame and then lay the Styrofoam down onto the wooden frame and add weight to it so the Styrofoam stays tight to the frame as the epoxy hardens. After that i use the saw to taper the bottom edge. I also add Styrofoam to the front triangle and taper that as well. Once complete you should go ahead and do that for both pontoons.

Note: The strut layout in the second pic is different then the layout of the of the struts in the previous page. The layout in the previous page showed the correct positioning of the struts.

Step 4: Completing the Pontoons

Completing the Pontoons

Now you can see both pontoons side by side. To complete them i add a wooden triangle positioned at the top, and lined up with each strut, this will be used for mounting the frame. To add some more buoyancy i also cut a full 2' x 8' piece of Styrofoam in half lengthwise (giving us two 1' x 8' pieces). I use epoxy to mount those onto the inside of the pontoons.

Now both pontoons combined give a buoyancy of 460 lbs when fully submerged. This seems like a lot but when you consider you wouldn't want more then 60 percent of the pontoon submerged (then you would be uncomfortably close to the water) and you might also have you weight towards one side of the pontoon then it seems this 460 lbs is just enough for one person to float comfortably. (i fit 2 full size people on but it sits very low). If you wish to be able to make this a 2 person boat you can add more Styrofoam sheets to the outside. Each 1"x 2' x 8' sheet once cut to a height of 17" provides 62 lbs of buoyancy when fully submerged.

These calculations are fairly simple to do on your own. First calculate the volume of the object (length in meters x width in meters x height in meters), this will give you volume in meters cubed. Then multiply the value you get by the density of water (1000 kg/m cubed) this will give you how many KG the object can float when fully submerged.

Step 5: Making the Frame

Making the Frame

To make the frame i cut my 2x4 s to 4.75 feet long and attached them to the pontoons using screws. I chose that width because it was just small enough that i would be able to fit the frame (when separated from pontoons) in the back of my van. Next i add the 2x3 piece down the middle of the boat. This is both for structure and to mount other parts off of.

Step 6: Adding the Keel

Adding the Keel

Now i cut out the keel out of a piece of plywood. Using the plywood, i also glue a slot so that the keel can be slid in and will be able to slide up and down within the slot.

The keel is an essential part of the sailboat and helps to turn the force provided by the wind into thrust in the forward direction. This is also the pivot point when you turn your boat

Step 7: Adding the Rudder

Adding the Rudder

The rudder will need to rotate so i decide to mount it off of a hinge. I add a hinge to the back of the boat and then cut the rudder out of the piece of plywood. The rudder should be fastened in place with 2 bolts and the bolts should have a washer in between the nut and the wood of the rudder. The bottom bolt will have to be taken while the boat is out of the water so that the rudder can pivot upwards when it is on dry land.

To finish off i add a handle made of plywood. The handle is to only have one bolt through it so that it can pivot up and down.

Step 8: Finishing Touches

Finishing Touches

To finish up i cut a piece of plywood to size and fit it on top of the catamaran to use as a seat.

After that we need to make somewhere to mount the mast of the sail. To do this i obtain a small piece of pvc pipe and heat the bottom of it so i can squeeze it down and make it thin. Once that is done i simply mount a few screws in it to attach it to the frame of the boat.

Step 9: Setting Up the Sail

Setting Up the Sail

Now i use a mast and sail that i had laying around and slide it into the pvc pipe. I secure the mast with metal cables that attach to various points on the boat. Once the mast is in place i rig up the main sail and the jib and it is now ready to sail

Step 10: Testing Out the Boat

Testing Out the Boat

Now that the boat is complete you can go ahead and take it out on the water and test it out. Be sure to wear a lifejacket and bring a paddle just in case you have a hard time getting it in using the wind.

To see the test you can also check out the video

Step 11: Schematics

Schematics

Here are a few schematics of the boat, they are not to scale. Beside the schematic picture i also attached a real picture of the boat

In order we have a top view of the boat, a front view, a side view, and a picture of the rudder and keel. All measurements of the schematics are done in meters.

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simple catamaran hull design

Discussion in ' Boat Design ' started by Ward , May 6, 2003 .

Ward

Ward Junior Member

I've been trying to design a simple-to-build catamaran, and I've come up with this hull design. This is just a sketch to give an idea of what I have in mind. I have never built a catamaran before, so I have no idea if this would be very efficient. The dimensions I have in mind are about 15' in length, and about 18" wide (beam). I would like to use 5mm ply for the entire hull as well. I've tried searching on google, but I really can't find much information on building catamarans, and especially not simple ones. Also, due to the deep-vee design, do you think it would be possible to have no daggerboard/keel and only have rudders? I imagine it would need oversized rudders however, since it probably wouldn't want to turn very well. Any comments/suggestions/information is greatly appreciated.  
Might help if I attach pic  

Attached Files:

emubo

emubo Junior Member

good idea - keep things simple I have just some suggestions: in my opinion the hull looks like one from a big boat (about 40 feet) - but on a 15' boat you will face other problems. The weight of your body relatively heavy on such a small craft. the v-shape plus the straigt sheer gives not very much bouancy for and aft. That means you would place yourself carefully on the boat and/or sail area is very small. Can you tell more about the intended use of the boat, can make things easier to discuss...  
Well, I live by a good sized lake, at its deepest part its probably 30 feet deep. Theres more than enough room to cruise for hours, and theres plenty of people sailing larger boats (20 to 30 feet) on it. I'm pretty much just looking to build a nice cruiser that can carry 2 people, but can be sailed by one. I would also like to fish from it, but thats not really going to effect the boat design very much. I'd prefer it to be as fast or a little faster than my friend's canoe with the 2 of us rowing. Is 10-15 knots unreasonable? I would also like to have something that can be disassembled easily and either car-topped or truck-bedded. My firebird doesn't have a trailer hitch and I dont plan to add one because it would just look like crap I can however borrow my dads pickup (also no hitch on it) for launching. Im open to all ideas, I am by no means set on this hull design. My ultimate goal is to simply have a working design, whether its of my own creation or not.  

icetreader

icetreader Senior Member

You may want to consider a cross section shaped more like a U than a V. It will reduce the wetted surface area, and consequently the drag.  

Ssharpsjc

Ssharpsjc Junior Member

shape is very important in hull design. The pic I saw posted would be easy to build but extremely difficult to turn and would have a terrible draft. For a simple hull construction in wood that is very inexpensive go to Kurt Hughes website at www.multihulldesigns.com and look at his cylinder molded process. This is not his exactly because I made a Tornado with this method in the early 70's from instructions I received in the mail form someone. This was a typical method for a quick construction of simple hull designs. I own a multi built this way and if I was going to build in wood, I'd use this method. Very inexpensive and very fast. A 30 foot hull will take a few days.  

emcmia

emcmia New Member

Catamaran keel design I have a P43 Privilege, 25 ft beam, 26000 lbs displacement with fixed keels. Each keel is approximately 14 ft in length and extend about 24 inches below the rounded hull form resulting in a total draft of 48 inches. The keels are essentially flat slabs with virtually no foil shape and average about 6 inches wide, flared into hull and tapered at the bottom to about 4 inch width. Underway, either under power or sail, especially in shallow water and hull speed over 8 knots, the boat tends to squat, progressively until the bow raises and the water line at the transom (i.e. swim platforms) is submerges as much as 12 inches. I have extended the swim platforms 48 inches which has resulted in adding at least 2 knots to the hull speed. However, the squatting effect has not changed. At the next haulout, I am considering changing the shape of the keels to a foil shape, similar to a conventional aircraft wing but symetrical on both side and tapering the trailing edges to less than 1 inch. The objective is reduce the negative pressure that I believe is occurring aft of the keels due to the turbulence created by the existing keel shape. That being said, I am concerned by the prospects of increasing the drag due to the increased width that will be inherent with new foil shape. Your comments and suggestions would be seriously appreciated. Thanx, in advance.  

gonzo

gonzo Senior Member

James Wharram desings cats that have a section and don't have keels or centerboards. I had a 34' and it sailed OK. Of course it doesn't point like a 12M. I think that you need less rocker and more freeboard.  

betelgeuserdude

betelgeuserdude Junior Member

Here's one simple catamaran design that sounds similar. It's supposed to be a pretty decent little boat. http://woodsdesignssailingcatamarans.com/quattrobuild.htm Building a Quattro 16 http://www.sailingcatamarans.com/quattro16.htm Quattro 16 DC  

sblevins

sblevins New Member

Plans are available to build the Taipan 4.9 from primarily 4mm ply. For its length it has very broad performance characteristics. A number have been homebuilt and the builders have posted their suggestions. Phillip Brander (Aus) has a site with extensive descriptions and pictures.  

Freestyle

Freestyle Guest

Catamaran You may well find that it is cheaper to buy a production catamaran. Hobie 14s (only for sailing solo) and Hobie 16s (for sailing solo or double) can be had for a couple hundred dollars, usually with a trailer (put a hitch on your dad's pickup). Check out E-Bay and BoatTrader. I have the Quattro 14 plans and they are very thorough. I bought them, not to build the boat, as a general "how to design and build a catamaran" guide. I'm currently designing a Formula 14 racing catamaran to be built in plywood. It will have canted hulls and dagger boards and hopefully blow every other 14' design (and some 16' designs) away. The first thing I learned is that 3mm is fine for the hulls. You'll use thicker on the deck and frames to strenghten the hulls. The lighter the boat, the better. Lighter boats will float higher and sail faster. The second thing I learned is that a rounded or elliptical hull shape is most efficient. A rounded-V, however, could be easier to build and is almost as efficient as the famous rounded U-shape. The V-shape is the worst hull design to date, giving the least amount of bouyancy and the most wetted surface. The third thing I learned is that 10" wide hulls would be better than 12" wide hulls for this racing boat. A 16' boat more concerned with cruising and carrying a load would do better with 12" wide hulls, but 18" is far too wide and will really slow the boat down. Catamarans need to have at least an 11:1 fineness ratio (11 units length per 1 unit width). The finer the hulls, the faster the boat, and the less weight it can support. I've more-or-less figured out the rig, and now I'm working on hull-rocker (the curvature of the keel is important to the maneuverability of the boat), and cross-sections next. Then I'll be able to start building balsa-wood scale models.  

sharpii2

sharpii2 Senior Member

Hi Ward A long time ago, I considered the idea of a dory like hull form for a catamaran. The advantage I saw was that it would be easy to construct and it would have less wetted area than a "V". Also (it was hoped) that the flat bottoms, which would be half the beam of the hulls, would get up and plane under really blowing conditions. Rather than bother with dagger boards, I intended to use long keels that were to be half the length of the hulls. These were to be slab sided and only tapered at the ends. What I had in mind was not a particularily fast ship. She was to be aprox. 15ft long and have about 100sft of sail. Her hulls were to have dry storage compartments too. Eight to ten knots was her goal speed. She might have been able to do better off the wind. I planned on a low aspect ratio rig which would be simpler, cheaper, and less hassle to set up. (I don't know how they manage with those 28ft hobie masts.) I was thinking more in the area of 18ft. A plain plywood box section which would be held up with a trystay arrangement. NO JIB. I hate jibs and usually sail without them. Besides, there is room for doubt how well one would stand with such a simple stay arrangement. Of course, any other catamaran on the lake would blow my design away in a race (but maybe not if it were asked to cary the same payload). But my design would be twice as fast as the same size mono (with the same level of crudeness) and would be able to be so, placedly. I applaud the idea of using the multihull concept for something other than pure speed. Why follow the crowd. Bob  

BIG MAC

BIG MAC Junior Member

hobie 16's have no dagger boards or keel. they use asymetrical hulls. they are light and fast and could be made drier if desired. they are a dime a dozen but watch for delamination at the forward pylons. much stress here and some fail. if you just want to build your own, look at the hobie 16 as a guide. you could easily stitch and glue the hulls and hobie sells (or at least used to) templates for the hulls for guides in re-fairing. if you build it and cruise rather than race, give the hulls a few inches more freeboard. the 16 is a wet boat.  

brian eiland

brian eiland Senior Member

emcmia said: I have a P43 Privilege, 25 ft beam, 26000 lbs displacement with fixed keels. Each keel is approximately 14 ft in length and extend about 24 inches below the rounded hull form resulting in a total draft of 48 inches. The keels are essentially flat slabs with virtually no foil shape and average about 6 inches wide, flared into hull and tapered at the bottom to about 4 inch width. Underway, either under power or sail, especially in shallow water and hull speed over 8 knots, the boat tends to squat, progressively until the bow raises and the water line at the transom (i.e. swim platforms) is submerges as much as 12 inches. I have extended the swim platforms 48 inches which has resulted in adding at least 2 knots to the hull speed. However, the squatting effect has not changed. At the next haulout, I am considering changing the shape of the keels to a foil shape, similar to a conventional aircraft wing but symetrical on both side and tapering the trailing edges to less than 1 inch. The objective is reduce the negative pressure that I believe is occurring aft of the keels due to the turbulence created by the existing keel shape. That being said, I am concerned by the prospects of increasing the drag due to the increased width that will be inherent with new foil shape. Your comments and suggestions would be seriously appreciated. Click to expand...
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BIG MAC said: hobie 16's have no dagger boards or keel. they use asymetrical hulls. they are light and fast and could be made drier if desired. they are a dime a dozen but watch for delamination at the forward pylons. much stress here and some fail. if you just want to build your own, look at the hobie 16 as a guide. you could easily stitch and glue the hulls and hobie sells (or at least used to) templates for the hulls for guides in re-fairing. if you build it and cruise rather than race, give the hulls a few inches more freeboard. the 16 is a wet boat. Click to expand...

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Boat Design Net

Electric boats

Flying electric ferries battle to smoothly sail commuters over the wave crests.

Avatar for Micah Toll

As electric boats slowly gain market share among recreational boaters, a different breed of silent, efficient speed boats is now targetting commuters. Hydrofoil electric ferries are coming to a river or lake near you, and multiple companies are working to make it happen.

I’ve had the pleasure of covering electric boats for years, where I’ve seen just about everything the nascent industry has to offer. But it’s the hydrofoil electric boats that are making the biggest departure from the norm.

Compared to traditional V-hull or catamaran vessels routinely used as ferries, hydrofoil boats use significantly less energy to travel the same distance on the water. Hydrofoils, which work like an airplane’s wing placed underwater, lift the entire boat’s hull into the air. With significantly lower resistance, the boat essentially flies while using as little as 20% of the same energy required by a planning boat.

candela p-12 ferry

Hydrofoil boats have been around for decades, but more recent advances have replaced older internal combustion engines with electric motors, taking these boats to the next level.

The biggest name in the game is undoubtedly Stockholm-based Candela , which first sailed its prototype hydrofoil electric boat back in 2016 and has been in production since 2018. The company began with multiple models of electric speedboats for recreational boating. Now, its newest model, the Candela P-12, is going commercial for use as a ferry in rivers, lakes, and archipelagos like around its home waters in Stockholm.

The P-12 has been undergoing water trials since last year , ahead of its first commercial operations.

One of its first operators will employ it on the world’s cleanest lake, Lake Manapōuri in New Zealand, where it is expected to replace 240 tons of CO2 emissions each year by replacing combustion engine boats.

diy catamaran hulls

While Candela undoubtedly leads the industry, other hydrofoil electric boats have cropped up in the last couple years. Vessev , an Auckland, New Zealand-based startup, has just announced the successful completion of two weeks of intensive water testing for its VS-9 electric hydrofoil ferry.

“We have been pushing the VS—9 less than two weeks after its first flight and she has been ticking all the boxes and more,” announced Vessev CEO Eric Laakmann earlier today. “On some of our test sessions, we had 25 knots gusting 35 with wind waves to match and she was cruising over the waves.

According to the company, which released the video below, the testing occurred in sea states featuring chop and waves averaging around 75 cm (2’6″) and peaking at 100 cm (3’3″).

The VS-9 is designed to transport up to nine passengers, though Vessev claims to be developing a much larger 100-passenger hydrofoil ferry for larger operators.

San Francisco, California-based electric boat startup Navier also plans to target the commercial ferry market with its first model.

Debuted in 2023 , the Navier N30 announced its first official pilot program earlier this year. The hydrofoiling electric boat was said to be partnering with payment platform Stripe to ferry its employees from San Francisco’s outskirts to the downtown area.

The plan would showcase how the normally one-hour drive could be transformed into a much more efficient half-hour ferry ride on a hydrofoil electric ferry.

diy catamaran hulls

Electrek’s Take

I’ve test-driven a few hydrofoil electric boats, and I’ve always been amazed by how easy they are to operate and how smooth the ride is.

On Candela’s electric boats, I’ve been able to cut right across the wakes left by cruise ships while feeling barely a ripple.

Ferries can replace a significant number of cars in waterside cities, but making the experience more pleasant and efficient is key to getting more drivers out of their cars. With hydrofoil electric boats, not only do the journeys use significantly less energy, but they’re also smoother and more enjoyable. I’ll admit to being prone to seasickness, yet I’ve never gotten even a tad bit queasy on a hydrofoil electric boat.

Check out one of my last hydrofoil electric boat test drives below, where I took the Candela C-8 for a spin around Stockholm.

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Electric boats

Micah Toll is a personal electric vehicle enthusiast, battery nerd, and author of the Amazon #1 bestselling books DIY Lithium Batteries , DIY Solar Power,   The Ultimate DIY Ebike Guide  and The Electric Bike Manifesto .

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diy catamaran hulls

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IMAGES

  1. DIY Styrofoam Catamaran : 11 Steps (with Pictures)

    diy catamaran hulls

  2. diy catamaran plans

    diy catamaran hulls

  3. Fast build plywood catamaran ~ Sailboat optimist plans

    diy catamaran hulls

  4. Wood WorkDiy Catamaran Plans

    diy catamaran hulls

  5. Diy catamaran fishing boat ~ Free tunnel hull boat plans

    diy catamaran hulls

  6. Building a Plywood Catamaran

    diy catamaran hulls

VIDEO

  1. New Product Prototype

  2. DIY RC catamaran with DIY RC outboard (Part 1)

  3. 22ft Janus catamaran built in Poland Part 2

  4. Broken forebeam while sailing Cape York. Seawind 24

  5. 22ft catamaran Janus sailing in light winds in Poland

  6. Building a Sailing Catamaran

COMMENTS

  1. DIY Cruising Catamaran: Complete Building Guide

    If you were to build a 40-foot (12.1-meter) catamaran, your cost of materials would range between 20-30% of the total cost. Therefore, for $300,000 total, the boat's materials would range between $60,000 and $90,000. The hull tends to range between 15-35% of the total build.

  2. DIY Building Catamaran Hulls (1)

    The BIGGEST DIY project ever...building catamaran hulls. The catamaran hulls were built first, made up of internal frames, stringers, plywood, and fibreglass...

  3. Our Catamaran Build Kits

    The first step to building your dream catamaran begins with a strongback - this is a square frame used to position the temporary frames that will be used to form the hull shape. ... Once both hulls are turned the tops of the bulkheads will be used to join the two hulls, and then the bridgedeck component will be installed underneath. STEP 6.

  4. Catamaran Kit Process

    STEP 1. The first step to building your dream catamaran begins with a strongback - this is a square frame used to position the temporary frames that will be used to form the hull shape. This frame will be set up and must be square and accurate, a string or laser level can be used to achieve this.

  5. How to Build a Catamaran Boat? (Step-by-Step Guide)

    Start by laying the fiberglass over the frame of the boat. Make sure to cut the fiberglass to size and overlap the edges for a strong seal. Once the fiberglass is in place, mix the epoxy and begin to apply it. It is important to apply the epoxy in a thin, even layer to ensure a proper seal.

  6. Catamaran Construction with a DuFlex Kit

    Step 1. Kit Design. Work with us to finalise the details of the design you have chosen including any design options or additional modules to be included in the kit. We will determine the laminates, the number of panels required for each laminate, create the cutting files and prepare a quote for the kit if it is not already priced.

  7. Catamaran Construction

    The lightest, most expensive hulls are made from carbon, but a catamaran builder may use carbon in places other than the hull to add strength and stiffness. Carbon boards, rudders, and reinforcing structures can enhance performance without driving the price of the boat beyond reach. Carbon is the fiber of choice for many custom builds, racing ...

  8. DIY Catamaran Building Internal Fit-out (2)

    Building a DIY sailing catamaran is very achievable. The cruising catamaran hulls are now complete, it is time to consider the fit-out style for cruising and...

  9. Build your own A Class catamaran! :: Catamaran Sailboats at

    This is the first step in building a catamaran. The 3mm Okume plywood must be scarfed together. The scarfes are saturated with epoxy and then placed in a glue joint to make a solid glue joint. A skill, known in boat building as lofting, the skins which will make the hull are cut out of the lengths of plywood.

  10. Building a catamaran

    catamaran sailing. DIY boat projects on Pure Majek from new navigation equipment, anchoring systems, rewiring yacht electronics diagrams, AIS and much more. Its been ten great years since launch and we look at things that have worked and those we would change. Join us and be inspired.

  11. Building Your Own Catamaran

    Axiom #1: The hours to build a catamaran is. in almost in direct proportion to its weight. Which brings us to Axiom #2: Axiom #2: It takes about 1 hour to create. 1 pound of finished boat. In our case we spent 3,500 hours ( click. here for full details on the construction hours) to build a 4,000 lb. boat.

  12. 15' Coastal Power Cat

    LOA: 15'-6"; LWL : 13'-9"; Beam: 6'-11"; Draft: 10". Weight of structure: 450 Lbs. Materials: Marine plywood, epoxy. Maximum capacity: 8 persons. The Flat Cat hull is a new and efficient concept and is within the capabilities of many amateurs to build. The hull is a "false" catamaran with a tunnel that's partially immersed.

  13. How To Create the Perfect Cruising Catamaran Layout

    The Prismatic Coefficient (Cp), a measure of how full the ends of the hull get, is the most essential design hull shape factor for any catamaran. A high Cp equals high speeds, although you can still use a lower Cp if you have fine hulls. Nevertheless, the key to a good Catamaran design is a higher Cp for fast sailing.

  14. Catamaran Hull Design

    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.

  15. Easy to build catamaran for amateur boat builders

    This easy to build catamaran is intended to allow anyone, no matter their background, to build a modern cruising multihull with a thrilling performance and an appealing design with a small budget.. The Bora-Bora 28 has a very practical interior lay-out with accommodation inside the hulls and a large platform to be used as a sundeck.

  16. Kurt Hughes Multihull Design

    Order the Latest Design Portfolio today to see over 85 multihull plans in stock. Besides illustrating my stock designs, for which I sell study plans and full construction plans, it also contains my design philosophy of multihulls; an article on the rapid Cylinder Mold (pdf) or Cylinder-molding (in html) multihull construction; examples of ...

  17. 24 Foot Sailing Trimaran : 27 Steps (with Pictures)

    The main hull is made from a pair of old 16' catamaran hulls cutoff and glassed end-to-end. Junked catamaran hulls are easy to get. If you can't find a free hull, build a hull like the Kenya Canoe but bigger. Use scavenged plywood from crates if you want it free. ... DIY Electric Kayak by BradenSunwold in Boats. 152 16K ...

  18. Bruce Roberts, CATAMARAN boat plans, CATAMARAN boat building

    This CATAMARAN was designed to be built using the FIBERGLASS panel construction & special pre-scaled drawings are supplied for each hull panel making it simple for the builder to build all of the hull and superstructure as one complete unit. This is a POWER-SAILER CATAMARAN .. the bias is about 60% power and 40% sail ...

  19. Home

    Step by step how to build a Catamaran. DIY small boat plans. Wooden boat plans. Videos of how I built a Catamaran - 40 ft. A 3 year. Tokyo Express. Tokyo Express; ... Do you want one hull or two? Deciding between a catamaran and a monohull is a big decision and one worth... Going fast - in small boats - hull speed. by Tim Weston | Sep 30 ...

  20. Catamaran and Trimaran Boat Plans

    Catamaran & Trimaran Boat Plans from Hartley Boats make it a reality to build your own multihull at home. Build with Plywood or Fibre Glass. 12-35 ft plans. ... There are some unique challenges building a multi-hull sail boat, the extra beam added by each hull for instance can create storage issues while under construction. Hartley boat plans ...

  21. DIY Styrofoam Catamaran : 11 Steps (with Pictures)

    Step 2: Assembling a Pontoon. The catamaran will be composed of 2 pontoons. These pontoons will have a frame filled with the white, less durable Styrofoam in the center; then we will later add the pink Styrofoam to the outside. To start off i lay out two 2x2 pieces of wood with the white Styrofoam pieces in the center.

  22. The $21K catamaran: Build a cat fast and cheap

    A new edition of The Coastal Passage has just been posted. Click on the image at right to download the PDF. Covid Cruising! From Tasmania to Greece with a boat built by the editor. For more information on this boat, see and check out The BareBones project. The $21,000, 30 foot+ Catamaran! "PLANS" NOW FREE!

  23. simple catamaran hull design

    Catamaran keel design. I have a P43 Privilege, 25 ft beam, 26000 lbs displacement with fixed keels. Each keel is approximately 14 ft in length and extend about 24 inches below the rounded hull form resulting in a total draft of 48 inches. The keels are essentially flat slabs with virtually no foil shape and average about 6 inches wide, flared ...

  24. Flying electric ferries battle to smoothly sail commuters over the wave

    Compared to traditional V-hull or catamaran vessels routinely used as ferries, hydrofoil boats use significantly less energy to travel the same distance on the water. Hydrofoils, which work like ...