Multihull Structure Thoughts

Foiling is the future of sailing for many but now it is an expensive reality with the cost of foils for larger boats unrealistic. Why are they so expensive? Let’s look at a producer of foils for larger boats both monos and multihulls.

Avel Robotics has pioneered the use of AFP for increased reliability in complex-shaped and -loaded CFRP hydrofoils, used in offshore racing sailboats such as the new IMOCA-class racer. Luc Talbourdet the boss of Avel Robotics said “There was a problem, because some of the hand-layup prepreg foils were breaking.” Issues included variability in quality and delamination. Adrien Marchandise, co-founder and now Avel’s CTO, had been hired by Talbourdet to complete his PhD research on making foils using automated fiber placement (AFP). After significant investigation, the two saw a path for more reliable, high-performance foils and Avel Robotics was formed in 2017.

Avel Robotics owns two Coriolis Composites (Quéven, France) C1 AFP machines, each applying up to eight tapes with a layup precision of ±0.2 millimeters. The company has progressed from 15-kilogram foils for the first 26-foot catamaran for the Easy To Fly class (ETF26) to its current 300-kilogram foils for top IMOCA boats. For IMOCA boats, the foils can be described as C-shaped and are very long and thin. They have a somewhat S-shape, thanks to a “shaft” section that attaches into the hull and allows the foils to be extended and retracted. The 300-kilogram hydrofoil mentioned above measures 6-8 meters long with a 0.5-meter radius in the curved elbow. “One pair of hydrofoils takes one month for design and five months to produce,” says Marchandise. See the 60 foot monohull jpeg,

This software platform to design the foils includes Catia and SolidWorks plus other CAD and CAE tools. “Our design includes many different parts that will be assembled.” These include the main load-carrying spine, or stock, foam sections and a trailing edge and leading edge. “We produce all of these different parts using a variety of techniques,” says Marchandise. “We then assemble these 3D puzzle pieces.” The result is a very complex, highly loaded and weight-optimized hydrodynamic structure.

A foil profile is made up of 5 parts.
A layered series of central spars comprising of intermediate modulus carbon fibre laid either side of corecell foam
At the front and rear of the of the central spar a foam core with a high modulus carbon fibre nose and tail structure
Then the entire foil is wrapped in additional carbon fibre.

The central spar carbon fibre layers are laid up by the robotic arm ATP. “We AFP onto a flat mold table using tow steering to ‘draw’ the curved stock plies. The stock width is also not constant but narrows toward the foil tip. We use a variety of fiber orientations, designed to handle the loads in each region.” These include 0° plies that follow the longitudinal axis of the foils and 90° cross-plies. We also use 45° plies in the curve of the foil to increase delamination resistance from shear forces,” says Marchandise.

Completed layups are vacuum bagged, followed by autoclave cure at a pressure of 7 bar for 24-72 hours. Cure temperature ranges from 80-180°C depending on prepreg supplier and type. “Laminate thickness drives cycle time due to exotherm,” notes Marchandise.

The carbon fibre layers are epoxy glued to the Corecell foam sections and autoclaved again to form an integrated structure. The foil is then finished with the forward foam carbon fibre sections attached. “We hand layup dry quasi-isotropic plies around the bonded structure and infuse it with epoxy resin from Sicomin [Châteauneuf les Martigues, France],” continues Marchandise. “We can’t use prepreg because the foil’s chord length will gain two to three millimeters when it cures due to thermal expansion. This dilatation of the composite primary structure, which is positive through the thickness, causes springback issues in the skins [i.e., deviation in the molded shape due to thermal effects]. To avoid this, all skins are made using wet layup or infusion. To use prepreg, we would need one that cured at 40°C.”

Translation of all of the above. 5 months of design and intricate carbon fibre layup with the carbon fibre strength and fibre orientation laid up very precisely by machine and hand layup. The foil components are cooked in post cure ovens at a variety of temperatures, pressures and times. Before hand finishing the foils. This is not a cheap process.

Avel then successfully branched out producing some wing component products for the aircraft industry. These foils are successfully used on global racing Imoca boats. There is a reason they are expensive. The jpegs give an idea.

Additional edit. This is just one approach to building foils. AC racing catamarans have high strength carbon either side of Nomex cores then the hollow foil has a light foam filling. These work well for short course racing where the water is cleared of rubbish prior to an event. The HH series of cats use heavy carbon fibre skins and internal spars on there C foil daggerboards. Cost, a set of foils for an AC boat about $400,000. A HH 66 C foil daggerboard about $80,000. A set of foils for an Imoca 60 foot global racer $200,000 plus. I have to wait a year or 2 before I can go foiling.

 

Hi Oldmulti,
Thank you for taking the time for my adventure of finding the "perfect design" for me, or at least as near as possible.
With your knowledge about multi`s, i`m sure you would be the right person to advice me in this endeavour.
to answer yur question :

A cruiser/racer about 50/50 lets say. And in my opinion the KD105 would be 40/60 more racer than cruiser.

Strip planking would have my preferece only because i could use lokal (cedar) woood. Money wise that would mean a big saving above all other imported material.
But i could settle with ply. It would be design dependend i think, because it could mean far more construction time, for some designs i assume.

My ideal would be that i could build the whole cat in in my garden under a temporary shed. For launching at the waterside, it woud have to be transported in parts for just a short distance but due to some twists and turns the parts should not extend 40 foot long and maybe around 6 foot wide. Such as an individual, complete hull.
If for instance the nacelle or pod would be wider will not be a problem because it would be much shorter to maneuver.
At the nearby waterside are no facilities and i could only use it for just a day or two in the open, to align the hulls and bolt them together and call for a crane to launch. From there i will have to bring it a few miles to a protected bay. It should be by than as far finished that i could sail or motor it and be able to close up everything.

For any more work needed for assemble, join or finish, i wil have to transport all parts to a comercial shipyard more far away and rent or build a big shelter for cover against sun and rain.
This in my case here would cost me more than all the materal together. This money i could better use for all the equipment and rigging, needed to complete my boat.

Therefore i think a so called tube-cat such as the KD105 is the answer, but those come for obvious reasons in smaller sizes. Not really able to carry enough for two simple person to stay for longer periods of time and travel save and comfortable. Mostly island hopping and spending lots of time in bays on anchor or beached on sand. Longer distances with some extra provision, could be planed ahead. I would not like to sail a heavy loaded boat on it`s waterline and it would mean motoring due to low windspeed we often have here.
I don`t know how much a complete or customized design would cost me, but i would not mind to spend more on the design to my liking, than on imported core material. If that would envolve more work for me, i don`t mind, I`m for free.

Again thank you for your time and interest. regards voodoo child.

 

Voodoo Child. As a starting point look at Richard Woods Gypsy 28 design. It hulls can be built in plywood or strip plank western cedar or fiberglass. All options available. it can be made and virtually completed in a back yard in 3 parts and the crossbeams. All can be transported to the waters edge and if you are organized with a few friends the Gypsy components could be put together in a week for launch. Gypsy 28 are real ocean cruising boats and have crossed oceans. They can cruise 2 in comfort and can sleep 4 if required. Attached is the web site and the second web site has details.
Gypsy budget ocean cruising catamaran by Woods Designs http://www.sailingcatamarans.com/gypsy.htm
Gypsy study plan index http://www.sailingcatamarans.com/1gypsy5index.htm

Many have been built and have reasonable resale value. Also Richard and the Woods user group provide excellent support as people build. The smaller you can go, and still get your accommodation, the cheaper it gets. The speed of boats this size in real world use of cruising is not that important. They will all average 7 to 8 knots and hit 15 knots on the odd occasion.

 

Mike Leneman’s (MultiMarine) Minette is an example of a demountable 40’ Cat.

Interestingly from our conversation he mentioned he took a page out of Skip Johnsons book after seeing his arm and socket demountable beam design back in the day, and built his beams the same way, so they plug into sockets in the hulls versus using round aluminum tubes. The cabin/cockpit are then a separate component that attaches after the beams are inserted.

Here are some photos from his website along with some words from him about Minette:

“Before there was Corsair, before there were folding trimarans, there was a Concept 40. Minette is my take on a Concept 40 by Craig Ashby. Launched in 1984, Minette is a demountable, trailerable, 40 ft. catamaran made from cold-molded spruce veneer hulls and a composite and plywood cabin. Four bolts and 2 pins and the boat comes apart. On the racing end, she is the most “winning” multihull in California and at one point held the course record for the Santa Barbara – King Harbor race for over a decade. Today, after 30 years of sailing she is still winning races and going strong……a testament to wood/epoxy construction and advanced design.

On the cruising end, we have driven her, on our own truck and trailer to Florida (where we cruised to the Bahamas) and to Baja ( where we cruised the Sea of Cortez).

Major Innovations:
1. Ability to raise the 58 ft. aluminum, rotating mast without a crane, using the boom and boat winches for leverage and power.
2. Largest demountable, self-trailerable multihull in the U.S.
3. Very light construction, mixing modern composites with wood/epoxy simplicity to make a very durable boat. “

 

Here is another idea on the foldable multihull. This concept is a monohull power boat that turns into a trimaran when moored or in very calm conditions. The concept was submitted in a design ideas group. The folded boat is 23.5 x 8.5 foot folded and can unfold to 23.5 foot wide.

The FINES foldable multi-hull boat can accommodate 4 to 6 people and expand itself into a trimaran with double the deck area. With folded hull, FINES is a power boat able to fit into marinas or docks, when unfolded it becomes a “mini island” offering its guests a spacious platform and freedom of movement on deck. When in closed mode, those 3 hull elements are interlocked into each other resulting in compact size.

The helming position is located at the centre of the boat but a removable handheld control unit can provide you with great flexibility, you can easily operate the boat from a sitting position or from outside. You can lower the helm/control panel when not in use to get more deck space. There’s an autopilot feature as well. Spacious lounging areas at the front can be pulled out to create chairs and a table. There’s a built-in grill at the middle of the table for preparing warm dishes, storage space and drinks drawer can be found underneath. No mention of a toilet which on such a party boat may seem an oversite.

Back to the folding concept. As you can see from the jpegs the hull sides move out from the centre and as they do so, folded floor panels on either side unfolds to form a flat deck area. The “control” of the unfolding or folding is a secondary beam system fore and aft which operate by “taught control lines”. I suspect some hydraulics or electric motors would be a better option.

Now there is the basis of a good idea here that would need a bit of modification. The first item is the volume in the outer hulls (boat sides) would have to be reasonable to support the weight of 6 partying people looking over one side. Second how that float shape is integrated into a “monohull” overall shape would be interesting. The beams to get to 23.5 foot wide is the equivalent of having to sliding beams 8 foot long attached to the hull side floats, those beams would have to be staggered fore and aft at EG the rear. That means the float/side could only be 150 mm wide. Not much buoyancy. Result I would suggest an unfolded beam of EG 17 foot and have 1.5 foot wide hull side/floats.

An interesting idea. Back to reality tomorrow.

 

The Gougeon brothers of West Epoxy fame designed and built many designs over their lives. Here is a quick overview of some of the boats. The jpegs show each boat.

The first craft is a kids barge but the basics were there. It sailed but was not fast. As the brothers grew up, they went ice yachting that sparked their interest in speed. Some ideas of ice yachting were tried in E-1 an experimental tri that was very light and had to many moving parts. Meade considered this 1963 multihull “a disaster”. Meade’s constructed his second experimental trimaran, Pencil, in 1964. Built much too light, Pencil broke under her own weight shortly after her launched.

In 1965, Jan built a new tri Wee Three II to be sturdier, and to meet IYRU Class-C rules. The tri was rigged with a wingmast, much like a DN iceboat.

In 1965 Omega, a 25′ tri built was built and was the first boat designed with articulating amas. This experimental tri performed very well at Yachting’s One-of-a-Kind Regatta in 1965. This success on the racecourse brought notoriety to the Gougeon name in multihull circles. Next came Meade Gougeon designed and built Victor T, which he launched in 1969. At just 320 lbs, she earned the distinction of being the lightest Class C competitor in the 1969 Nationals in Hamilton, Ontario. There, Victor T took home the win against a strong field of wingmast-powered catamarans. These 2 tris had an ability to sail faster than the wind in very light airs. Very few people thought it was possible to build wooden boats of these dimension so light that would hold together. This was the fore runner of some very famous boats.

Now we arrive at a very famous tri. Launched in 1970 and pictured below in 2018, Meade Gougeon’s 35′ trimaran Adagio was the first large, all epoxy bonded and sealed wooden boat built without the use of fasteners. Meade and Jan Gougeon constructed her in just six months. She’s still competitively sailing 50 years later. Adagio is proof that epoxy-bonded monocoque structures can last for generations.

In 1977, they built Rogue Wave, a Dick Newick-designed tri, for Phil Weld to race in the 1980 OSTAR challenge. This 60′ cold-molded trimaran was among the larger boats the Gougeon brothers built.

This 1979 Gougeon-designed and built Flicka , a wooden cruising tri that capsized in the Atlantic in 1980. Sailing solo, Jan Gougeon spent four long days in Flicka’s capsized hull. He had plenty of time to think about rightable trimaran designs before a passing freighter rescued him. Flicka had to be abandoned at sea.

In 1980, Jan began building Splinter, following his terrifying experience aboard Flicka, he designed this developed plywood trimaran to be rightable if capsized. Splinter was launched with a wingmast. This was followed in 1984 by Ollie which was built using the Gougeon brother’s developed plywood technology. The design was the Stressform™ 35 along with Stressform wingmast plans. Ollie’s design further advanced Jan’s ideas for self-righting multihulls. After the Atlantic capsized of Flicka, every boat he designed was self-righting. Splinter and Ollie had wide beam for power but had small floats which allowed the tris to righted if they capsized.

Adrenalin was built in 1987 for Formula 40 racing. The tri performances unsettled European sailors so much after its first races that they changed Formula 40 rules to legislated Adrenalin out of contention. Adrenalin is a Formula 40 Trimaran with articulating amas. This boat amazed the sailboat racing world by taking an extremely close second place during her first regatta: the Formula 40 Grand Prix circuit in Brest, France, in 1988.

The G-32 is a 32’catamaran designed and built by the Gougeons in the early 1990s. These production boats feature a water-ballast system, are self-righting, and are trailerable. The masthead float doubles as a wind vane and prevents the boat from going completely upside down if capsized. The Gougeons conceived the G-32 as an affordable cruising and racing vessel but it didn’t achieve market success. The 14 built are still racing and sailing today.

Jan Gougeon’s final boat was Strings, a 39’7′ “folding cat with a fuselage. He launched her in 2011. She has long, narrow hulls and a center cabin that rides above the water. An elaborate network of lines (aka strings) makes this ingenious boat perfect for solo sailing. Although Jan passed in 2012, Strings still competes in regattas on the Great Lakes.

All off these boats are light, innovative and are designed to sail fast. The early failures lead to some very fast self righting boats with features that worked. The only issue is the majority of the boating public wanted more accommodation for a given size of boat. Well done.

 

Astera 42 is a volume production cat designed by Berret-Racoupeau Yacht Design for Fountaine Pajot. This is a sportier pure cruising catamaran. The Astera 42 is 41.3 x 23.7 foot with a weight of 23,000 lbs and a maximum displacement of 35,000 lbs. The 60 foot carbon fixed mast carries 710 square foot mainsail and a 430 square foot roller furling overlapping headsail. Other sail options are available including a Code 0 and spinnaker. The length to beam on the hulls is about 8 to 1. The draft is 4.2 foot over fixed low aspect ratio keels. The engines are 2 x 30hp Volvo with saildrives.

This cat is about accommodation and reasonable performance at a reasonable price. The accommodation is vast for a 42 foot cat. 3 or 4 cabins in the hulls with attached toilets. The 3 cabin version has one full hull dedicated to a master suite. This could be a home for some. The bridge deck cabin has a galley/kitchen area that would not be out of place in some apartments. The galley is placed between the main cabin and cockpit which both have seating for dining etc. The helming and sail handling position is on a raised portion of the starboard forward in the aft cockpit. This cat does not come with a self tacking jib as standard, so electric winches may be required for some folk.

Now down to the structure. The hulls below the waterline are solid glass as are the fin keels and are glued on so they can be replaced if involved in a serious accident. The infused hulls employ balsa core in the topsides. The decks are built using the RTM approach with injected decks and are cored with foam. The RTM method has an inside and outside mould so when you infuse the polyester resin into the fiber glass etc you get a smooth outside and inside (gives a clean roof). All the bulkheads are composite laminates, though Alpi wood is used for the furniture and trim. This is pure production building. A real production 40 foot cat can be built in 2000 hours, a “custom” production using hull moulds may take 6000 hours, a home build may take 10,000 plus hours to achieve the same finish. The initial costs to start up a real production run are considerable.

The performance of an Astera 42 is good. To quote “We test sailed the boat in light fall weather on Chesapeake Bay, when the breeze failed to rise above 6 knots. Still we had a nice sail, nearly notching 4 knots of boat speed both upwind and on a reach” “In light air, it delivered 3.6 knots of boat speed in 7.1 knots of apparent wind at a 60-degree apparent wind angle. As we hardened up to 45 degrees off the wind, we still kept up 2.8 knots in 6.3 knots of breeze—not bad for a cruising boat in these kinds of conditions.” In 15 knots of wind in a 4 foot chop “With a minimum of effort we were doing between 8 and 9 knots, which was not bad at all! Later under screecher (a gennaker in spinnaker cloth) in a slightly gentler breeze, we bore away to 140° off the wind which was between 8 and 9 knots, sometimes, 10 and instruments reported a peak at 12.1 knots.”

This is a good potential global cruiser that has some performance capability. The jpegs tell part of the story.

 

A drawing of Adrenalin's articulated ama.

 

Thanks, very interesting drawing . I think "Drag Strut" is not the adequate name, obviously it counteracts yawing moment on the ama,
related to lateral force (lift !) , not drag force ! I wonder why this system had no follower ! Adrenalin had some success in F40 circuit.

 

patzefran. Adrenalin independent hull movement has been done by a few others but it has a few issues. The get the balance between a hull moving in a differing wave sequence is hard. The float may be climbing a wave being pitched up as the main hull nose is still going down. Each component needs to be design as independent components to a point. When Rob Denny designed his light weight W cat that has one beam which allowed the 2 hulls act independently he found less problems but there is a limit to how much movement you can have.

Next it took a little time to learn how to sail Adrenalin to get the best performance. It like foiling cats and tris, it takes time to learn how to drive new things.

Finally JSYD discovered that with correct distribution of the center of buoyancy between the floats and mainhull a rigid platform can reduce pitching in a trimaran. That pitch reduction may have been of more value than allowing independent hull movement. We need more information.

 

I am going to present one main jpeg to you. This is the reality of home boat building. Many people start with a dream and good intentions, then you reach this point. What you are looking at is the cockpit area of a F 32 trimaran. This appears to be a carbon fibre foam glass build. Ian Farriers plans are some of the best in the business (if you can find an unused plan and want a tri, they are worth owning).

I am not saying there is anything wrong with the structure but look at how many parts and actions it would have taken to build this cockpit area alone. In this jpeg there are over 40 individual parts that needed to measure to have foam cut out, cloth and resin done on both faces, trimmed and fitted. If there are any access openings you either have to put a hard edge in or rout out foam to put in bog or a strengthening material to reinforce the access hole edge etc. Then the panels needs to be bogged into position have any rounded rounded corners applied and then faired before tapping into position. This is before you fair the surfaces inside and out before you do final paint preparation and finishing.

There are at least 100 tape joints that need to be done in this cockpit jpeg and some of them are in difficult to access locations. And the joy is each one has to be sanded and finished. As Fallguy has said about his Woods cat build, incorrect taping can add weight and time to a build. Having many parts that need to be aligned can add time and when you get to EG completed hulls that then need to be aligned with crossbeams to allow the completion of a structure some times requires cranes.

But prior to building the parts in the cockpit you need to know what deck gear is going to be used and where it is going to be placed as hard points need to be put in the foam glass sandwich to absorb the winch loads, turning blocks etc. Also you need to understand your engine installation, helming solution, instrument layout etc so any hard points or access points are allowed for. Finally are there appropriate points to store winch handles, extra rope, immediate access to safety gear, clip on points for safety harnesses etc.

Next comes the real trick, even good plans sometimes specify hatches, ports, deck gear etc of products that existed when the plans were drawn but 10 years later that product doesn’t exist. I know some people have a garage full of boating gear that was purchased at the time of the plan buy and have an unfinished boat. And I know others who have a near finished boat that requires modification because the add on parts specified in the plan does not match the hatch size that is currently available. Be warned.

I am not trying to depress anyone but look realistically at a boat build. The fewer the number of parts the easier the build, the smaller the boat the easier the build (no always but in general). If you can create a full length flat panel foam glass hull side that has a clean ready to paint external surface you made life easier. If you can plan how to build a large deck panel with all the inserts pre set in and things like hatch sizes understood life becomes easier. Just building a shell then adding things later sometimes is a lot more work than planning as much as you can prior to building.

Good designers do a lot of the planning for you providing a design that includes hard points etc and the deck gear etc that is required. You the builder, need to build the boat sensibly according to the plan sequence (if available) and understand if the deck gear etc is still available. Boat building is not hard, just long and at times intricate and messy.

Have patience do it properly first time without short cuts and you will be proud of your achievement.

 

I saw an interesting drawing of a TS3 cat (first jpeg) and read the item where a person said he was “currently working on a similar boat, lighter and with a little extra power, for her to be sailed in Finland. I've you're looking for a more "modern" touch.” Interesting comment.

So, I looked up the author of the comment Alan Cattelliot and found the second jpeg. It is of Franck Martin, Jack Michal, Gilles Ollier, Yann Penfornis, Alan Cattelliot. The team associated with Multiplast a world leader in composite multihull design and construction. A yard that has produced high tech multis like Crédit Agricole III, Jet Services I, II, IV & V, Elf Aquitaine II & III, Commodore Explorer, Région Haute Normandie II, Biscuits La Trinitaine II, Club Med, Innovation Explorer, Team Adventure, Geronimo, Orange II and now Groupama 3. OK, I am listening very hard.

We have mentioned TS3 before which is a Christophe Barreau design, and is a demountable catamaran that is 36 x 18.2 foot that weighs 4,200 lbs and displaces 6,000 lbs. The 48 foot wing mast that carries a 475 square foot mainsail, a 205 square foot solent jib, 538 square foot genoa and a 775 square foot gennaker. Length to beam is about 13 to 1. Draft ranges from 1.3 foot to 6.8 foot over the very high aspect ratio dagger boards. The rudders are kickup on the stern. Engine power can be electric outboards.

TS is short for Tres Simple (Very Simple in French). The boat is basically 2 hulls with minimal internal accommodation, 2 carbon fibre main crossbeams, a fore aft central spare for the forestay attachment and an accommodation nacelle that contains 2 double berths, seating and a basic galley. The accommodation cell has sitting headroom. The accommodation cell is a maximum size of 18 x 8 foot. The result is the total boat can be disassembled and towed on a trailer. It would need a crane to assemble and disassemble it.

The TS3 is built by resin infusion of glass, PVC foam and vinylester resin. The Carbon fibre box beams are full width of the boat and are strapped to the hulls at the gunnels. The TS3 is fast, in the initial tests in Lorient the TS3 reached 18 knots in 12 knots of wind speed. I could accept this with new sails and an empty boat with smooth water. Back to the original comment, Alan said he is “currently working on a similar boat, lighter and with a little extra power”. In the TS 3 we are dealing with a very fast boat able to exceed wind speed.

Now there is going to be a lighter version with extra sail power. This will be a real racing weapon that has 2 double berths, seating area and a small but effective galley in the main saloon (not full headroom). There are toilets in the hulls. I would imagine with Multiplast skills, the new design will be mainly be carbon fibre foam epoxy and I have seen 36 foot cats with 55 foot masts. Result we have a cat that is approaching very fast speeds for a non foiling cat, which will exceed wind speed across a broad wind speeds.

Hopefully we can get more details on this cat when it is completed. The jpegs are of the current TS 3.

 

This is about a home designed and home built series of tris to suit one person’s needs. Hans Schipper wanted a tri and initially started with some modified boat parts (EG Finn mono main hull and Coolcat floats) to form a tri called Cool Finn which was later named Triple A. Triple A worked well with speeds up to 13 knots in force 5 winds. Unfortunately, when on a trailer a Force 10 wind arrived and blew the tri of the trailer cracking the deck area. Result a new main hull was started after an acquaintance offered an unfinished hull from another project.

The maximum size Hans could trail was 19 foot so a tri was born that would be 19 x 10 foot that had sliding beams to reduce the beam for sailing. The floats are the hulls from the Coolcat catamaran The 31 foot mast carried a Nacra 18 square mainsail (193 square foot) and a variety of jibs. The main hull weighed 330 lbs the total rigged boat weight is unknown. The outboard is 4 HP. Hans wanted foils on the floats from the initial design to add stability to the 10 foot beam. He thought about best shape for canards (foils on the float and main hull rear) to minimise resistance and maximum lift. He did not want a fully flying tri just some additional stability and minimising leeway.

The foils contribute well to stability and provide noticeable lift from a boat speed of 8+ knots. The antifouling wears off visibly faster on the front of the profile. Thanks to the 45 degrees backwards, no aquatic plants will stick to it. The top speed I measured is almost 12 knots at gusts of 4 Beaufort. The average speed over a longer distance is around 6 knots with a wind of 3 Beaufort. The wing profiles give slightly less lift than expected. With the 45-degree angle, they release the water plants well.

The construction of the main hull looks like a solid glass external shell to the gunnel with plywood decks and strengthening shelves etc. The cross beam support tubes in the main hull are PVC with Hans saying “As I experienced with the Cool finn I am glad with the pvc-tube layer that covers the sliding ama tube. That makes sliding lighter (easier).” The cross beams are aluminium tubes permentaly connected to the floats. The original mast collapsed after the wooden mast step failed and was replaced by a metal structure. Hans is willing to develop the tri until it works the way he wants. Good effort.

There are several short videos of Triple B sailing and it appears to sail and handle well. A good 2 person day sailor with a small cabin area for storage etc. The jpegs give the idea.

 

I am curious about the steering controls on the TS3. Second last image (ts3 cat 11) shows tiller steering with rudders/tillers connected via the tiller bar, with a yoke on the starbord rudder with one or two connections into the hull. I am guessing this is for an autopilot?

 

Stefan, Alan Cattelliot is active on the "Self Righting Multihull" and "Demountable 30+ to 40+ cat" threads. I would suggest you put the question to him there or DM (PM) in the inbox (conversations) at the top of the page. He knows the details of these boats better than most. Good question, if you get an answer please let us all know.