scarab trimaran

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Scarab 10 - A trimaran for getting into amateur building

Article published on 01/04/2021

By Emmanuel van Deth

published in n°177 may / june

Admittedly, this mini-multihull is probably one of the smallest there is - except little training boats for kids. And yet, one or even two adults (as long as they’re not too heavy) can sail it, as the central hull is beamy enough to offer significant buoyancy.

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Discussion in ' Multihulls ' started by Brorsan , Feb 6, 2011 .

Brorsan Junior Member

I'm thinking of building the scarab 16 ( http://www.teamscarab.com.au/scarab16/design.html ), but there is so little info about it. Seams like only 1 boat has been built. 5m tri at say 500kg fully loaded, that wount be very fast, will it? All info is appresiated. Thoughts of it? Is it simply TO small for a tri?  

I think i was rather unclear in my last post.... I'll take it from the beginning. I'm interested in building a small trimaran, and i dont want to spend a fortune neither spend to long building it, one year buildig time maximum, starting about half a year from now. I will use the boat mostly for daysailing but allso some weekend sailing. I got all fittings, mast, boom and sails from an flipper dinghy, that is a total sailarea of 11sqm upwind. So, i'm interested in building a scarab 16 and use the flipper stuff to build a really cheap boat for me, and i do know that this will be a little underpowered but i live on the west coast of sweden and a avarage summer day we got around 5-7 m/s wind. If it turns out to be a nice vessel and i find a used beach cat for a good price i will later upgrade to more sailarea. What i've been thinking of is if this is to small to be a good boat, maybe the interior is to small to be useble at all, and the waterline simply to short for getting up speed. I would like to sail at the same speed or faster than a 9m older monohull, could that be possible (with larger cat mast and sails)? I've allso been thinking that going up in size to the scarab 18 would greatly increase both performance and interior volume, but the cost would allso increase. Small boats small problems has been said alot of times. Farrier from f-boats have said that the F23 is the smallest trimaran he will ever build because of just speed, interior and seaworthiness. I should allso add that i have ordered and looked closly through the study plans for the scarab 16, and that i have built a monohull with pinestrips before(more like a bigger canoe). So i kindly ask for your thoughts about this, you dont have to know anything about it, just give me your thoughts. I have never sailed a multihull. The scarab 16 got a sailaway weight of 200kg, that sound pretty much to me, thinking of using thinner plywood and reinforcing it on the inside to save some weight. Sorry for that massive wall of text, but please give me your thought, especialy on the sailing performance and seaworthiness. Is this to be seen as a toy? Or is it really a micro cruser? Thanks in regard /Brorsan  

rayaldridge Senior Member

I don't think the size of the boat is the limitation you should be concerned about. Your proposed rig is very small-- about half the sail area of a beach cat. My little 16 foot cruising cat has been criticized as being under-rigged, but has 140 sq. ft. of sail-- more than the flipper rig. But Slider has that small rig because she has only 8.5 feet of beam. Still, even though she is a heavy boat-- may displace 1100 lbs when loaded for cruising, she still is faster than many monohull yachts that are much larger. I don't think you have to worry about the boat being slow, if you have an adequate rig. The question of accommodation is something you have to decide in personal terms-- can you overnight in a cabin that small? If so, it's big enough.  

Thank you Ray for your thoughts, discussion and thought sharing is allways good for decisions. I know that the proposed rig is very small, and it would only be used initialy i think. Also i was wrong about the wheight, 400kg (880lbs) is probably more likely crusing wheight. What do you (and others) think about the seaworthiness of the scarab 16?  

Well, the problem with any small multihull, when discussing seaworthiness, is that stability goes up so fast with size. Big multihulls can be extremely safe, because the forces needed to capsize them are enormous. Since multihulls do not recover from capsize as ballasted monohulls do, in that sense you are always taking more of a chance with a very small multi than you take with a very small monohull. On the other hand, it will be harder to capsize that multi than that monohull, and monohulls can sink. Much depends on where you intend to sail the boat. One good thing about a small multi is that it will be unsinkable (or should be.) If you have an EPIRB and an immersion suit, you should be able to survive a capsize, but most of us would not want to find ourselves on a capsized boat of any kind in cold northern waters.  

luckystrike Power Kraut

Brorsan said: ↑ Thank you Ray for your thoughts, discussion and thought sharing is allways good for decisions. I know that the proposed rig is very small, and it would only be used initialy i think. Also i was wrong about the wheight, 400kg (880lbs) is probably more likely crusing wheight. What do you (and others) think about the seaworthiness of the scarab 16? Click to expand...

Thank you again Ray, and a huge thanks to you Luckystrike, that was exactly the kind of thoughts and information i was looking for. I allso think it looks to be made heavier than necessary, and actualy mailed Ray Kendrick about it a few days ago. I will be very very glad if you would like to have a look at the drawings if/when i order the plans. Funny that you mention stretching out the mainhull, caus that thought have passed my mind aswell. I'll get back here a little later and ask some more questions when i got a little more time. Regards /Brorsan  

the scarab 18 is allmost the double wheight compared to the 16,a the sail area 16m2 compared to about 22m2 for the scarab 18. I guess this means that the 18 will cost aprox 70-80% more than the 16, does that guess seam fair? My plan is to build this boat and use it for a couple of years, and when i hopefully get children (about 5 years from now or something like that hehe) i'll sell the boat, and i guess i wount get much for it weather it is 16, 18 or 20 foot long. And some years after that there will probably be a bigger tri or cat, but that is to far from now to speculate on. I'll think about the scarab 16 for a while, but it sure looks lik a good multi hul entryboat for me considering cost and buildtime.  

Brorsan said: ↑ the scarab 18 is allmost the double wheight compared to the 16,a the sail area 16m2 compared to about 22m2 for the scarab 18. I guess this means that the 18 will cost aprox 70-80% more than the 16, does that guess seam fair? My plan is to build this boat and use it for a couple of years, and when i hopefully get children (about 5 years from now or something like that hehe) i'll sell the boat, and i guess i wount get much for it weather it is 16, 18 or 20 foot long. And some years after that there will probably be a bigger tri or cat, but that is to far from now to speculate on. I'll think about the scarab 16 for a while, but it sure looks lik a good multi hul entryboat for me considering cost and buildtime. Click to expand...

Hi, its me again ... the guy with the sick brain! Just played around a little bit :idea: , because I wait for a buisiness date, but have a look and have fun! The Data on the upper left corner are for the Original. The Mainhull seems to be a little fat now, but thats because the now black mainhull is "melting" together with the cabin windows. If you do the "stretching" the length of the Amas (floats, outriggers) should follow their mainhull in length, of course. I just gained 5 cm of sitting headroom too! To be honest, I would'nt tell this Ray Kendrick! Michel  

Attached Files:

Hehe, funny again, i've also played with the thought of doing a wavepiercing bow, and made some simple sketches. Your sketch show how i really would like the boat, but then the drawings would have to be redrawn completly for the hull and amas, right? It could be done relativly easy in "carsson hull design" though. How did you gain 5cm of headroom? Was it by adding volume under water?  

Brorsan said: ↑ Hehe, funny again, i've also played with the thought of doing a wavepiercing bow, and made some simple sketches. Your sketch show how i really would like the boat, but then the drawings would have to be redrawn completly for the hull and amas, right? It could be done relativly easy in "carsson hull design" though. How did you gain 5cm of headroom? Was it by adding volume under water? Click to expand...

Very informative and interesting i must say! The 2m cockpit leangth is a very good thought, really make sense, specialy in a boat with this low volume inside (and no foredeck hatch) can for sure be pretty hot as you mentioned. I get it all, except the deck part. Will the deck, the cabin, and the cockpit be strecthed too? (that means the whole boat streched leangth wise) And dont you think it will be rather problematic to cut off parts of the bow considering the 45 degree angled panels? (second from the deck)  

DriesLaas Weekend Warrior

how about 17 feet Hi Brorsan, I have just finished the concept sketches of a boat which I want to build for myself. It is 17 feet long, I think the Scarab 16 is just too small. I have a rig with 20 square metres of sail area (Prindle 18 beachcat) which is a lot, but I think the boat will sail really well. I have increased the size of the cabin enough to make comfortable upright seating, and there is two pilot berths for sleeping. The galley and toilet will all be removable for racing to keep the mass down. The volume of the amas is 670 kg, which is ample for even the cruising weight. I hope to build the boat of marine ply, to a weight of 250kg rig included. Racing weight is then 400 kg with two crew, and cruising weight is about 120 kg more (food, water, battery, sleeping bags, galley, porta-potti toilet etc.) The beams will fold in the style of Farrier and Scarab. The foils will be very nice modern 505 centerboards and rudder, racing mode will have the centerboards in the ama's. For cruising one centerboard in the main hull. Rudders mounted on the ama's for now, I want to try it to see. I can give you the drawings when they are done to have a look at.  

sr_multiview.JPG

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That look very nice DriesLaas But i must ask, dont you think it will be back heavy with the cockpit that far aft? And you also need some space for the rudderstick in the cockpit (about 1m) Are you building right now, or how long until planned building start?  

Folding system - like scarab trimarans

Possible rig for Scarab 18

Nacra 5.2 vs Solcat 18 mast. Which one for my Scarab 18?

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Astus Boats Are Now Available in the USA!

Jun 27, 2022

It comes with great pleasure that Red Beard Sailing is now the official US dealer for the brand new line of Astus Boats !

Design & History

In 2004 Jean Hubert-Pommois created Astus Boats. When they got started Astus was only making 7 of their first design the 20.1 in their first year. Now, 17 years later, there are over 400 Astus boats sailing all over the world!

Starting in 2015 Astus sought out a refresh in the model range. As a result, Astus hired world renowned naval architect firm, VPLP, to completely rethink and redesign the Astus range from the keel up!

VPLP is a premier naval architecture and yacht design firm based in France. The firm is well known for their pioneering sailboat designs that have broken numerous speed records. Successful racing sailboats from VPLP include Hugo Boss, Groupama 3, and America's Cup winner Oracle. Continuous innovations in hull forms and foil shapes have kept VPLP Design at the top of the leaderboard in the most challenging regattas in the world.

Performance

The new age of Astus Boats has ushered in a new definition of speed for these small portable trimarans. These boats offer exceptional handling and performance in a small and manageable package. These boats offer a few key design points that really make these  small trimarans exceptional:

Narrow Hulls: Skinny hulls slice through the water and waves with ease and provide better light wind performance as well as more comfort in poor and choppy conditions. Typically, narrower hulls means you have less buoyancy, but when used in conjunction with the inverted bows, these boats actually boast more buoyancy than your average production trimaran.

Inverted Bows: Hull speed is a mathematical calculation (speed in kn = 1.35 x square root of waterline length). Inverted bows maximize waterline length by making sure the longest part of the boat is the below waterline (BWL) length. This means the Astus boats will be faster in light winds and will get on plane in lower wind speeds than other boats with traditional overhanging bows. In conjunction with the narrow hulls, the Astus trimarans are very comfortable in a chop because they do not hobby horse as much as more common tri's.

Infusion Construction: The infusion method for constructing the Astus trimarans ensure that the hulls are as lightweight as possible. Less weight means that these boats are faster and can carry more weight, safely, than other similar sized trimarans.

Astus is famous for their telescopic carbon beams that allow their boats to be road trailerable. This style of beam offers a number of benefits over competitive folding and swinging style folding systems.

Less Weight: It doesn't take a big imagination to see this obvious advantage. Other folding / portable trimarans have overbuilt fiberglass beams in order to equal the rigidity of a simple carbon tube.

Fewer Moving Parts:   The Astus Telescopic Beams are a simple locking pin and slide, no special tools, parts or hardware are required to maintain or operate.  Complicated folding systems have many bushings and specific geometry that must be maintained. In addition to all of those extra parts comes lots of hardware that must be checked regularly. 

Easier Transport/Storage: Because the telescopic beams slide in a linear way, the bottom of all three hulls remain the bottoms. Unlike the Farrier designed boats, the Astus boats can easily be moored or docked in a monohull slip. This often means finding a slip is easy (shallow water monohull slips are hard to rent for marinas)! In addition to being easier to store in the water, getting a boat back on a trailer touches the bottom of the boat instead of beautiful painted sides gives you a little more wiggle room and less anxiety when launching and retrieving your boat. The beams also allow the boat to require much less height on a trailer which may make all the difference between indoor and outdoor trailer storage in the winter.

Less Intrusive: The Astus beams do not require beam boxes or mounting hardware that intrude on the interior cabin. This is a massive perk on trimarans under 30 feet where space comes at a premium. If you plan to do some weekend cruising with the family, you will very much appreciate the extra storage and sleeping space!

Manufacturing Process

Astus Boats is located in the Morbihan region in northwestern France , just near The Trinité-sur-Mer and the Gulf of Morbihan. It is no wonder they make such amazing sailboats!

Astus boats does everything they can to keep manufacturing and sourcing local, in France. They design and build the molds locally and even source sailmaking and other boat's components from other French manufacturers. In case you aren't aware, France is the sailing-est place on the planet. Keeping the whole boat French means that every Astus is imbued with the spirit and love that the French have for the sport of sailing!

Affordability

Astus has long prided itself in offering quality, performance sailboats at a price that will allow would-be adventure seekers all over the world, from all walks of life, to enjoy the passion and performance that you get with an Astus trimaran.

Without further ado, below are specs and base prices for each Astus model:

An ultra-portable personal Tacking Proa or Trimaran . You can choose to sail with two hulls or three with this exciting and affordable trimaran! Easy to car-top, this boat can go from car to water in just 5-10 minutes! 

A high octane beach trimaran that is easily portable but offers plenty of space and capacity to take the family out for a relaxing (or sometimes sporty ) daysail! This is a great boat for the family to enjoy and for Dad (or Mom) to race in local regattas.

The ultimate nomadic weekender. The 20.5 is a bit bigger still than the 16.5 and has a cabin! The addition of the cabin in the 6.0m category means that you get way more boat for your buck than other production trimarans on the market. You also benefit from the other features listed above that makes this the perfect family starter boat as well as being a great day / weekend charter boat!

The largest boat in the current Astus lineup . This boat features a much larger cabin than the 20.5 and a bit more speed. Down the line, this boat will be offered with optional foils in the floats to allow for higher speeds in rougher conditions. This wouldn't make this boat a completely foiling boat, just foil assist in the leeward hull. Red Beard Sailing currently has one of these boats in production for our demo fleet. It is slated to arrive in Baltimore in May 2023, so keep an eye out for our un-crating and first sail videos!

To learn more or to discuss the next steps to purchase your new Astus boat, please email us at [email protected].

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The adventure of the construction of a folding trimaran.........

SCARAB 22 by Ray Kendrick

I BUILT my boat in glass/foam sandwich panels. (why...)

Lessons learned .

Design Modifications.

Building time:1500 hours.

TRIJUL is sold and will now be moving to a new home for the 2011 season!

Summer 2010 : 4th season sailing.

Summer 2009 : Sailing.

Fall 2008 : Sailing, tuning.

June 2008 : New sailing season!

February 2008 : Redesigning diamond spreaders (many fun FEM hours!)

Winter, 2007-2008 : Merry Christmas! Nothing to report...Water is hard!

Some extra summer 2007 photos

September,2007 : Sailing...

August, 2007: Sailing...

July, 2007: Sailing, fine tuning, enjoying (as many hours as possible, not counting!)

June 24th, 2007: Launching (several hours but not counting anymore)

April, May and June, 2007 : Lots and lots of little things. (110 hours)

End of March, 2007 : Interior painting, cabin windows (48 hours)

March, 2007 : Centerboard, engine, stuff (46 hours)

January, 2007 : Installing fittings (69 hours)

October, 2006 : Boat assembly (60 hours)

End September, 2006 : Centerhull painted (21 hours)

September, 2006 : Both floats are 100% done (62 hours).

August, 2006 : One float painted, one almost ready to go(112 hours)

June, 2006 : Still mixing putty and sanding stuff (101 hours)

March, 2006 : Centerhull glassed (59 hours)

January, 2006: (38 hours)

December, 2005 : Centerhull stuffed. (54 hours)

End of October, 2005: Stuffing centerhull (18 hours)

October, 2005: Centerhull right side up! (22 hours)

September, 2005: Centerhull ready to be flipped over. (60 hours)

June, 2005: Centerhull assembly started. (45 hours)

May, 2005: Floats completed. (29 hours)

April 10, 2005: One float assembly done. (17 hours)

March 26, 2005 : Beam-float assembly, chine taping (22 hours)

March 10, 2005: 4 beams ready (85 hours)

November 14, 2004: 8 half beams ready (48 hours)

October 10, 2004: Done with the floats, making beams, mast (17 hours)

September 25, 2004: Progressing with the floats (19 hours)

September 15, 2004 : Light sanding, fitting "redesigned" transom. (2 hrs)

September 13, 2004 : Fitting float top panels, template adjustements,found a mast!. (7 hrs)

September 10, 2004 : I am becoming a putty expert...(5 hrs)

September 6, 2004 : Assembling top portion of floats.(11 hrs)

August  29, 2004 : Assembling floats, fillets and tapes.(23 hrs)

August 08, 2004 : Assembling floats !!!.

July 30, 2004 : Cutting beam cap laminated sheet.

July 24, 2004 : Laminating beam caps, ready to assemble floats and beams.

June 14 2004 : First 4'x 24'foam panel(3 hrs.)

June 11 2004 : Fwd spar web and Spar bushings(18 hrs.)

May 23 2004 : Aft spar web(6 hrs.)

May 20 2004 : Upper forward spar cap(2 hrs.)

May 16 2004 : Fwd spar cap2 (1.5 hrs.)

May 15 2004 : Fwd spar cap(2 hrs.)

May 09 2004 : Aft spar cap(6 hrs.)

May 03 2004 : Spars(10.5 hrs.)

April 27 2004 : Vacuum pump, first de-bag(2 hrs.)

April 25 2004 : Vacuum plenum, first panel(5 hrs.)

April 19 2004 : Peel ply, panel 01(5 hrs.)

April 16 2004 : Main spars templates(2 hrs.)

April 15 2004 : Fiberglass corner angles, laminating table (6 hrs.)

April 03 2004 : Received fiberglass, perforating polyethylene (2 hrs.)

March 28 2004 : Making holes in foam (7 hrs.)

March 26 2004 : Major valve! (1 hrs.)

March 22 2004 : Corecell foam delivery (2 hrs.)

March 21 2004 : Full size templates (8 hrs.)...

March 17 2004 : Full size templates idea (2 hrs.)...

March 14 2004 : Laminating table (5 hrs.)

February 26 2004 : Resin infusion, FEM.

February 19 2004 : Received epoxy.

February 14 2004 : Ordered the materials.

February 9 2004 : I received the plans!.

January 30 2004 : Waiting... (tube trimaran FEM results).

January 22 2004 : Plans mailed to me today!

January 16 2004 : Ordered plans for the scarab22.

Click on the buttons and watch the legs spread...(hahaha!)

One happy day it occured to me that a light trailerable boat would be ideal in North America, especially up north, where the season is so short. During winter, one can drive south and go sailing (Pensacola anyone?). There are also hundreds of lakes that make wonderfull destinations. For example, it took me 6 days of boring motoring up the St-Lawrence seaway in my old keelboat to reach Kingston, Lake Ontario, from Montreal. With a trailerable boat, only 3 HOURS are required!!!. It becomes a possible weekend sailing spot. When I discovered that small trimarans were available, I had the feeling that I just woke up!

Design/Construction/Technical info

Composite chine joining methods...

Essential links

Scaled Composites (check the "PROJECTS" tab for flying trimarans...)

Duckworks Magazine

Kendrick Design

Schionning Designs

Woods Catamarans

Mail to: Olivier Blanc