Multihull Structure Thoughts

Discussion in 'Multihulls' started by oldmulti, May 27, 2019.

  1. CocoonCruisers
    Joined: Dec 2015
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    CocoonCruisers Junior Member

    Awesome thread oldmulti,
    so much to learn so quickly from all these compact real-world case-studies,
    and what a delight to still see generous people fostering transparence, like in the early days of the www.
    Thank you so much !

    I'd also be curious to read your thoughts and stories about design pressures, slamming loads, and greenwater impact failures.
     
  2. oldmulti
    Joined: May 2019
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    oldmulti Senior Member

    Yesterday we spoke of an old foiling design Spitfire. Today we will speak of a very advanced foiler. The Gunboat G4, a foiling “cruising boat”, underwent successful sea trials looking an exciting boat. Then, in its first regatta, the G4, capsized in 30 knots of wind. The boat was being sailed by an expert crew when a puff hit and the fully powered-up G4 went over.

    The G4 is 39’10” x 22’3”; Draft 1’10” (boards up), displacement is 5,950 lbs with a sail area of 1,378 sq. ft. With boards down the draft is 8 feet. The boards are L-shaped, hooking inboard at about a 90-degree angle. T-foils are mounted on the deep rudder tips. The hulls have wave-piercing bows and almost a chine aft and are purely designed for high speed. The accommodation is limited with the saloon headroom of 5 feet. There are settees port and starboard with double berths outboard. The head is in the port hull with sitting headroom. You cannot access the areas in the hulls from the saloon. The G4 is vacuum molded using epoxy pre-preg carbon skins on Nomex honeycomb coring. Designed payload capacity is a generous 1,600 kg (3,530 pounds), although performance will doubtlessly drop when the G4 is loaded to the max. The boat has done 25 knots in 14 knots of true wind speed and has done higher top speeds.

    Now back to the capsize. Multihulls stability, for a given length and beam, is partially controlled by a low centre of gravity and a low as possible centre of effort in the sail plan. When a boat like G4 gets up on foils it centre of gravity and centre of effort rises 5 feet and due to L shaped foils the effective centreline of “hulls” (read foils) narrows. The G4 also increases boat speed on foils increasing effective wind speed over sails and over turning moment. In short the righting moment of the boat reduces as the G4 gets up on its foils or the faster the G4 goes the less stability it has. America Cup foilers crew train full time for 2 years to sail there boats for 40 minute races in controlled conditions and they occasionally nearly capsize.

    The latest version of the G4 has semi automated adjustable foils and the one design racing version called the F4 has an even more advanced foiling control system.
     

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  3. oldmulti
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    oldmulti Senior Member

    The Eagle 53 cat began in 2016 when Donald Sussman, owner of a 90 foot Gunboat cat, discussed the prospect of a new boat with his big cat’s captain, Tommy Gonzalez. They were talking about a new foiling cat. Sussman casually said, “Wouldn’t it be great if we could put a wing on it?”

    When Sussman said “wing,” Gonzalez’s had a sketch he had made long before, of a special “wing mast” rig. He knew that somehow it must be able to weather vane into winds from any direction. Discussions with Randy Smyth resulted with the notion of cable rigging leading to the very top of the mast. It would attach to a swivelling mast cap that would not rotate but instead allow the wing mast to rotate beneath it a full 360° without hanging up on its supporting stays. The masthead-only standing rigging would create an unprecedented span in the wing, from cap to step. They knew the physical properties of unidirectional carbon-fiber laminates (especially in compression) and a generous cross-sectional area, could be successfully engineered into a wing mast structure.

    To more than double working sail area for efficient performance, a special fabric mainsail would be set on the trailing edge of the spar. When set, this sail would not permit full rotation of the wing, but it could be reefed (needing only one reefpoint); and when downed completely, the soft sail would be totally detached, thereby permitting the wing to freely rotate 360°. They dubbed it the hybrid wing. It could be depowered and left standing when the boat is unattended or when running in gales at sea. With only three synthetic rigging cables and its super streamlined shape, this wing would have absolute minimal windage on all points. Gonzalez and Smyth believed in the concept but had no place to apply it until Sussman said, “Wouldn’t it be great if . . .” The eagle 53 concept was born. The boat is 54 x 28 foot weighing 13200 lbs and displaces 16,600 lbs with a 78 foot carbon hybrid wing mast.

    Her construction is lightweight prepreg carbon-fiber skins over honeycomb and foam cores, with very specific layup schedules and lots of unidirectional carbon reinforcements, which, according to structural analysis, are arranged to parallel the load paths. All components were vacuum-bagged and post-cured in an oven. Some parts were autoclaved. Eagle’s overall configuration exemplify Bieker’s approach. The stems angle is reversed, so the hulls are longer at the water than at the deck. The upper forebody is sharply crowned, whereas the forward underbody is almost flat. Also, the highest point on the freeboard is way aft. Even without hydrofoiling, the long, low, wave-piercing bows can steer their way right through crests without asking the whole boat to climb over them. In rough going, wave piercers work their way through a seaway better. And if the boat is steadier, so is the rig. The air can establish stable flow over both sides of the wing to draw the vessel forward instead of pushing it aside. This yields improved windward ability, deeper reaching, and less stress on the boat (40% less load on the mainsheet), plus a smooth, dry, and quiet ride. Eagle began life sailing on C-foils. In this “semi-foiling” mode, she power-reaches at boat speeds in the high 20s with winds in the mid-teens. When showing off her C-foiling in more wind, she can skip along at boat speeds in the 30s with one hull flying high and the other is still partially in the water. To fully foil the boat is going to need T-foils and automated ride control that will allow amateurs to successfully take the helm at 30 knots, and safely depower the boat when conditions become excessive. According to the design brief, such foils should make the Eagle 53 fly flat with all foils in the water and all hulls out, with boat control at speeds approaching 40 knots.
     

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  4. oldmulti
    Joined: May 2019
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    oldmulti Senior Member

    We are going to talk about the future of boatbuilding. 3D printing. 3D printing is a technique of using a “computer” printer to build a 3D object. It can be a plastic figure, a metal car part, a rocket motor, artificial skin or part of a boat. 3D printing depends on special “inks” and temperature controlled environments to build the parts layer by layer. The layers are about 0.1 mm thick so it takes some time to build an object. The success of this approach also depends on the suitability of the printer’s feedstock—a polyamide with 25%–30% of carbon reinforcement called PA12. Small 3D printers have put the layers onto a base plate that can be heated up to “cook” the plastic ink as the part is built. Large 3D objects require a temperature controlled environment (room) to cook the part as it is built.

    The huge advantage of 3D printing is a designer can design a boat on a CAD program then feed it into a 3D printer and the boat will be printed out very accurately. In theory no humans required. Reality is we are not there yet. The first 3D print was for a power cat lower hull mould, but the most advanced is a 650 mini racing mono of 21 x 10 foot that weighed 2000 lbs. The winner of the last Mini-Transat weighed 1650 lbs. The hull shape and basic 3D structure is shown in the jpeg’s. The structure is printed in four parts that will be joined with structural adhesives. Added to this base isogrid structure is carbon skins of biaxial 300 gr (8.8 oz) and uni-directional 150 gr [4.4 oz], with a vacuum-infusion system and is post cured. Also important is the reinforcement of high-load areas such as the keel box, the shroud, and the rudder attachments. The mast and boom will be built from prepreg carbon and cured in an autoclave. The rudder will be 3D-printed with a hollow structural core and sheathed with woven and unidirectional carbon fiber. The keel fin will be produced with a 3D-printed mandrel for the central structure comprising thick laminated carbon layers, while the fairing will be added later with minor composite reinforcement.

    These are early days in 3D printing, but as the technology develops, on demand custom boats will be able to be ordered and printed in a few weeks without any shape compromises for ease of building. The 3D hull mould took 8 days to print.
     

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  5. oldmulti
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    oldmulti Senior Member

    John Marples/ Jim Brown make a great design pair. The Seaclipper 20 day sailing tri is an example. The boat is 20.5 x 15 foot sailing or 8.5 foot wide when trailing. The base weight is 800 lbs with a load capacity of 600 lbs. The sail area can be from 170 to 240 square feet depending on which beach cat rig you choose. The mainhull and floats have dory bottoms. And are designed for easy construction. Marples tends to design strong boats capable of absorbing a few knocks. The mainhull bottom is 10 mm ply, main and float hull sides 6 mm ply, main hull transom 19 mm ply, bulkheads 6 mm ply. The hulls have a stringer, chine and gunnel timber. Main hull decks are 9 mm ply. The folding component of the forward cross beams are 250 x 50 mm timber on the flat. They could be laminated from 2 layers of 25 mm for extra stiffness. The mainhull beam support assembly is 2 layers of 250 x 50 mm timber. The rear beam components are 200 x 50 mm timber. Look at the PDF’s on the net to get the idea. The folding crossbeams use 12 mm stainless steel bolts as pivots and lock bolts. The float decks are 12 mm ply. There are additional 12mm ply discs on the float deck and support timbers on bulkhead under the deck where the cross arm attaches to the float. The float also has vertical ribs about every 500 mm for further hull support. These boats sail well and are a lot of fun for there owners. But like all designers Marples wanted to improve the concept and built Syzngy a round bilge 21 foot version of the tri for himself. Syzngy has strip plank cedar bottoms on the hulls and curved laminated cross beams of 250 x 50 mm. Marples will not sell the design as he considers it too much work to get the curves for the size of boat, but he is very happy with its performance. The following blog tells you a lot about a Seaclipper 20 build. Building a Seaclipper 20 in Italy http://seaclipper20.blogspot.com/
     

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  6. oldmulti
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    oldmulti Senior Member

    Cacooncruisers asked “I'd also be curious to read your thoughts and stories about design pressures, slamming loads, and greenwater impact failures.” I am NOT a naval architect, take the following as an amateur response and I am sorry it will be in PSI (pounds per square inch). There are conversion factors on the web to translate it into Kpa or kgN/m2. The base information came from https://espace.curtin.edu.au/bitstr...5859_Grande K 2002.pdf?sequence=2&isAllowed=y and another source later.

    For all sea states the maximum number of water slams are seen in head sea, and drops when the vessel bears away from head seas. And the most frequent slamming occurs in sea states with waves closer together. Also practical experience of ship’s crew show when slamming occurs at full speed the problem is made worse by reducing speed. Finally the number of slams are seen to increase with increasing wave height. Slamming is a highly non-linear phenomenon, increasing the significant wave height EG from 3 to 4 meters results in a dramatic increase of the number of slams. If you are going at 10 knots up wind you may hit a wave every minute, down wind you may hit a wave every hour. The number of slams per hour is highly dependent on the speed, wave height and wave period. Studies found Crowther’s 318 is vulnerable to short period waves, at low speed. It is seen that the number of slamming incidents on the pod is much larger than the number of slams on the main beam. The average impact velocity follows a similar trend, with most severe impacts at low speed in short waves. The main beam is shown to experience larger impact velocities than the pod, even though the pod will experience more frequent slamming.

    The average impact velocity varies according to boat speed, wave speed and wave height. But assume a max of 3 knots to 5 knots above the sailing speed. Sailing at medium speed, 10 knots results in more slamming than sailing at high speed, 15 knots or low speed, 5 knots. This result is different from the result obtained earlier when the boat was sailed on one hull for all speeds, and it is obvious that modelling the ship motions at a proper sailing attitude is important for slamming. It is also clear that the pod experiences the most frequent slamming. The pod is obviously slamming quite severe both in the 1.5 meter sea state and the 2.25 meter sea state while the main beam is in a much better position. It can be clearly seen that most slamming impacts are light, with a smaller number of more severe slams. Slamming pressures can range from eg nil PSI to 3.2 PSI at 8 knot impact speed with a maximum of 32 PSI if you have a very large ocean wave with a breaking crest. These hits last for under a second. Slamming pressure and the number of slams change with different wave heights, wave period, speeds and headings.

    According to physicists, a breaking wave can apply a pressure of between 1.7 PSI to 41 PSI depending on its height. Some designers design for 4.5 PSI on their hulls to handle impacts. This is the classic case of what do you design for, a bullet proof boat that can withstand anything (even 50,000 tons ships have been broken in half by wave action) is going to be excessively heavy. A number has to be chosen that is realistic. Also the shape that hits the wave has a big influence. A flat plate hitting a wall of water will have the highest impact pressure. A bow shape will have far less total impact pressure.

    A second source tested GRP panels for a 30 foot 10,000 lbs power boat using a 3g loading on the bottom panels. The GRP panels were biax cloths with epoxy resin. The GRP panels were tested with pressures from 2.3 PSI to 6.9 PSI applied to the panels. Failures (micro cracking) started occurring in the panels glass fibre resin matrix at 4.7 PSI and complete failures started at 7 psi. The Effect of Slamming Impact on Out-of-Autoclave Cured Prepregs of GFRP Composite Panels for Hulls - ScienceDirect https://www.sciencedirect.com/science/article/pii/S1877705816340565

    Translation of the above. The power of waves can range from little to very large EG 6000 lbs per square foot (41 PSI). If you are in a boat in open ocean under a large breaking crest, good luck. You can only design for realistic sailing conditions. Some designers regard 4.5 PSI as a realistic maximum hull pressure to design too. Designers then say the hull structure should only deflect 1% of its length when 4.5 PSI is applied. The shape of the structure hitting the wave or water at speed significantly influences the impact.

    Experience of a 37 foot cat had its 12 mm ply underwing punch in by wave action going upwind. But a 12 mm ply 27 foot wharram type cat I know can slowly go through anything.
     

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  7. BlueBell
    Joined: May 2017
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    BlueBell Ahhhhh...

    Was Sea Shepherd wave damage or a boat strike from the whalers?
     
  8. oldmulti
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    oldmulti Senior Member

    Sea Shepard power tri was "Bridget Bardot". The damage was done by wave action not hitting any other object according to articles I have read. The damage looks like a wracking strain not a solid hit on the outside of a hull.
     
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  9. oldmulti
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    oldmulti Senior Member

    A deviation the Aspen power catamaran is actually a proa. It was designed to have the advantage of a single engine power boat whilst having a catamaran type shape. The power cat is 42 x 14 foot displacing 22500 lbs powered by a single Volvo D6 330 HP engine with a top speed of about 22 knots. The proa configuration allows the single engine to be in one fatter hull and the second hull being thinner creates less drag allowing the entire boat to run straight.

    All cross beams, bulkheads, transoms, and stringers are constructed from CNC cut Coosa composite ranging in thickness from 19 mm to 60 mm, Coosa is a PVC foam and fiberglass reinforced panel that is 45% lighter than plywood; it is waterproof and cannot decay. The uniquely engineered integrated rib, stinger, bulkhead system is solidly fiber glassed in place. A hand lay-up process utilizes a combination of premium knitted fiberglass materials, yielding the maximum strength with the least amount of weight.

    Hull lamination starts with a stabilized gelcoat. This is followed by a skin of 600 gram CSM with pure vinyl ester resin. The following laminations are done with high strength Isothalic polyester resin and includes multiple layers of 600gsm roving, 450 gram CSM, 3 mil and 6 mil Coremat in specific areas, knitted bi-axial fiberglass fabric, 19 mm PVC Divinycell foam, and Kevlar. The bottom of the hull is reinforced by 3 additional layers of mat and roving, along with a double layer of Divinycell. Total thickness of the double bottom is just over 60 mm. The entire hull and deck are bonded with aircraft grade cross linked urethane adhesive, then fastened with 316 SS fasteners every 75 mm. Finally, inside of the deck-hull joint is fiber glassed with 1708 Nytex.

    The interest here is the hull design to be optimized for 1 engine. Good thinking.
     

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    Last edited: Oct 4, 2019
  10. oldmulti
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    oldmulti Senior Member

    NASA’s Structural Properties of Laminated Douglas Fir/ Epoxy Composite Material, gives a lot of information about epoxy wood, strength and fatigue characteristic’s. Meade Gudgeon company made 4000 wind turbine blades from wood epoxy and NASA asked for the evaluation of the technology. It discusses shear failure, compression failure, quality of timber, lamination strength, joint types and strengths etc of basic timber and epoxy timber. https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19910000814.pdf or access the same PDF document which is attached and is 142 pages (8 meg).
     

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  11. oldmulti
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    oldmulti Senior Member

    Bali 5.4 is 55.5 x 28.5 foot with a weight 47,000 lbs displacement 63,000 lbs. The sail is a maximum of 2200 square foot. Anodized aluminium mast of 82 foot. Bali is the cruiser offshoot of Catana catamarans. These cats are floating houses with the Bali 5.4 claiming 1384 square foot of accommodation. The length to beam of the hulls are 7.5:1. This boat is a cruiser with a capitol C. Expect 8 knots speed in 20 knots of wind and 200 mile days if things are blowing in your direction. Not a racing machine. What’s the interest? This boat is reverting back to the old English style of catamarans with the bridgedeck going from bow to stern. Bali's claim the solid foredeck is the strongest construction for a catamaran design because it is part of the bow structure rather than a flimsy joint between the hulls. This contributes to the rigidness of the boat, making it much stronger than conventional catamarans with two bows joined by a crossbeam and netting. The acute angle of the underbody of the solid deck and the buoyancy of the solid foredeck cause the bows to lift up rather than dive into the waves which improves performance and safety even further. Bridgedeck clearance as a rule of thumb is 5 to 6% of the overall length. Bali meets this.

    The Bali catamaran is full-composite construction with Divinicell closed-cell foam core and is vacuum-infused, polyester resin. Anti-osmotic vinylester in underwater sections for protection. The Bali has substantial bulkheads throughout for structural strength. All the bulkheads are tabbed and laminated onto the hull and deck which ensures a very rigid construction. The structure is built on a matrix of box sections in the bridgedeck which enables an open-plan layout with no intrusive bulkheads in living spaces. The boat is built in 3 main parts with joint localised at the keel junction. The bridgedeck and inner sides of the hull built in one part for a maximum of rigidity. Hull made in GRP infused PVC Foam Sandwich, Deck in GRP infused Foam Sandwich with monolithic / plywood reinforcements. Partition walls made of layers of fiberglass and PVC foam. The photo’s give an idea of the plywood box structure in the wingdeck area. A great cruiser that can take your airconditioner, dishwashers, microwaves, multiple TV’s, 8 friends, wine coolers and because your environmentally aware your hybrid drive system and massive battery bank. Also everyone wants a 1200 litre fuel tank and 1200 litre water tank to support your 8 friends needs.
     

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  12. oldmulti
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    oldmulti Senior Member

    Now for something different. Frenchman Sébastien Roubinet and two crew plan to sail a hybrid iceboat/sailboat 1,620 miles from Alaska to Spitsbergen. French composites company Resoltech has provided materials for the several versions of the boat, called Babouche. During trials, the first, measuring 249 x 1610 (7.5m x 5.1m), was deemed too heavy, and then, in 2011, an 18 (5.5m) version sailed for 45 days in Alaska. Employing basalt fibers, Innegra (a lightweight high-performance olefin fiber; www.innegratech.com), and Resoltech’s “flexible epoxy system” R1600/1606 helped reduce the weight of the third one—a 20 (6.1m) prototype—to just 330 lbs (150 kg). That served as a platform for Roubinet to gain experience over two months on the Arctic Ocean, prompting a redesign for the current version: Babouche 2 is 2211 (7.0m) long and 710 (2.4m) wide. Sail area is 484 sq ft (45m2); off the wind it expands to 914 sq ft (85m2). Weight is 440 lbs (193 kg).

    For sailing on ice, the boat rides on two slides made of carbon/Innegra/basalt, and Resoltech 1020, engineered for flexibility and elongation. The skins of the pneumatic hulls were laminated with Innegra and basalt fibers, using 1600/1606 epoxy. The hulls must be able to withstand significant impacts as they bounce over cracks and sharp ice features, as well as changes in inflation pressure.

    Sébastien made the floats by hand, shaping a large piece of foam, and then laying up carbon reinforcements all over with a soft epoxy matrix to resist inflation pressure. He then had to destroy the polystyrene plug from the inside to get an empty float and close the transom to make it airtight as an inflatable tube. Everything—mast, cabin, rudders, and skis—is carbon, made with wet laminations by Sébastien but with the help of some prepreg fabrics, in eg the mast. The first photo on ice is of an early prototype, the other photos are the current boat.
     

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  13. oldmulti
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    oldmulti Senior Member

    The final on Norm Cross trimarans. The Cross 45 R was a preliminary design, I do not know if one was built. It appears to be a good structural compromise between his larger racers and his smaller designs. The tri is 45 x 29.5 foot weighing 7500 lbs with 930 square foot of sail area on a 51 foot double spreader aluminium mast rig. The hulls are cold moulded WRC timber 3 layers of 3 mm. The cross beams top and bottom timbers are 160 x 80 mm with ply fore and aft webs. The forward cross beam is 550 mm deep at the main hull, the aft beam is 400 mm deep at the main hull. It has the coke bottle main hull shape to allow for the fin keel displacement as was normal for Cross.

    The Cross 18 PDF is the best description I have seen of this very popular model. I know there are people who would love to get access to a set of plans for this boat but the guy who was “selling” the plans has disappeared. Anyone who can help with details would be appreciated. Enjoy.
     

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  14. oldmulti
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    oldmulti Senior Member

    More of the unusual. The following boat is fast, verified 37 knots in 18-20 knots of wind! But it requires a rethink of sailing. As kiteboarding has boomed globally so have some people been experimenting with kites on conventional boats. A Sydney to Hobart mono nearly got permission to fly a kite. A 50 foot tri that lost its mast in the Virgin islands sailed back to Florida using a kite as it was cheaper than getting a new mast to the islands. Rob Denny tried a kite on a proa. The Kitefoil boat comprises of two foiling out-rigger hulls supported by a central hull and controlled via crew on a large rotating disk. The entire boat is powered by a relatively average-looking kite controlled on board by a series of lines much like a standard kiteboard. Because they are prototyping and often pulling just one or two parts off a mold, they frequently machine molds directly, but for certain parts they will first machine a plug on a 5-axis CNC mill. To make the T-foils for the oceangoing Kiteboat, they machine plugs from birch plywood, and then laminate female molds off the plugs with carbon fiber biaxial fabrics.

    The actual T-foils are prepreg carbon fiber with a birch shear web. The hulls of the new Kiteboat are made from prepreg skins with a honeycomb sandwich core. Parts are cured in-house in a composites oven built into an insulated shipping container. For odd-sized parts, Montague and his team build temporary ovens to fit. The real advances in the Kiteboat are in the central control module which has hydraulic servo kite line controls and the variably controlled hydrofoils.

    Don Montague, principle of the Kiteboat project in SF. ''We made a lot of progress and realized hydrofoils were the best way to utilize the kite because of the lifting forces of the kite. It was also relatively dry and I was really tired of being cold and wet. Our first boat was a catamaran that flew on two T-foils and two J-foils. We worked on that for about three years and also built a bigger 30-foot boat.” Montague considers kiteboats are too complicated and dangerous for the general sailing public at this point. “On the latest boats, there’s a series of servos that the boat driver controls. Something you don’t see is that we’re actually changing the profile of the kite while we’re out there. We change it through pressure, but that’s all top secret. The way we depower and turn the kite is sometimes all done through an Android phone.”

    The team will attempt to sail the fifth prototype (currently under construction) from California to Hawaii in three days, a distance of approximately 2,100 nautical miles, ideally in a flat sea state and about 10 knots of breeze. This will have them traveling at around 30–35 knots until Hawaii. The photo's show several versions of the 5 boats. J foils earliest, T foil last.
     

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  15. oldmulti
    Joined: May 2019
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    oldmulti Senior Member

    This is not about power boats it’s about how they are built and its possible application to yachts. Marcel LaFond of Sympony boats in 2013 produced an all-epoxy 19 9 (6m) launch using a “hybrid composite sandwich” in which he vacuum-bagged a 1 (25mm) foam core to an inside skin of 4 mm okume plywood and to 0.09 (2.29mm) 5052 aluminum alloy sheeting for the external skin. Four panels, plus the transom, make up the hull, which is built over a jig and weighed 1000 lbs without the motor. The boat was outboard powered (115 HP) and capable of 40 knots. In 2015 his company produced a new electric powered boat. The Elektra model is a 20 6 x 7 6 (6.3m x 2.3m) center-console launch powered by an inboard Torqeedo electric motor. The boat weighs 2100 lbs without the motor and can travel at 15 knots. Its hull structure was the same as the 19’ 9” outboard boat.

    On the first Elektra boat rather than employ an okoume plywood in the deck structure, as in previous boats, LaFond used a product from Lamboo Technologies that is developed from bamboo. The laminated panels are marketed for exterior building walls and ceilings, trim, playground structures, handrails, screens, awnings, and—in what appears to be its first marine venture, thanks to LaFond—hull construction. LaFond thinks it can also be used for decks, railings, stair treads, and other components. It’s available in various colors; recommended finish is Sikkens Cetol. Here are a few mechanical properties of Lamboo Elements:

    · compression parallel to grain: 13,488 psi (93 N/mm2)
    · compression perpendicular to grain: 3,043 psi (21 N/mm2)
    · tensile strength parallel to grain: 21,465 psi–55,694 psi (148 N/mm2–384 N/mm2)
    · tensile strength perpendicular to grain: 543 psi (3.7 N/mm2)
    · flexural strength: 12,800 psi (88 N/mm2)
    · shear strength: 2,901 psi (20 N/mm2)
    · moisture content: 5%–9%
     

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