Multihull Structure Thoughts

bajansailor. The 4 links I have are below. Some are 2 pages some are a few comments. Also there is a jpeg of what may have been a Youtube series. Links are:
How a proa works / I'm making a 45ft one in Aluminum https://www.boatdesign.net/threads/how-a-proa-works-im-making-a-45ft-one-in-aluminum.63285/

Building a 45ft Aluminum pacific proa! https://sailingforums.com/threads/building-a-45ft-aluminum-pacific-proa.41810/

How a proa works/ building a 45ft aluminum proa https://forums.ybw.com/index.php?threads/how-a-proa-works-building-a-45ft-aluminum-proa.532963/

Building a 45ft Alu proa https://forums.sailinganarchy.com/index.php?/topic/214165-building-a-45ft-alu-proa/

 

Minimus 11 is an open deck catamaran design, 23.75 x 13 33 foot, which is about as small as one can go in an ocean-crossing multihull with enough weight-carrying capacity for a crew of two. Her carrying capacity is around 1,200 pounds, which the designer builder said is sufficient for the crew, gear and provisions for 4 to 6 weeks at sea. Her hulls are dory style with narrow flat bottoms and V-shaped sides. The rig is unusual, with 4 masts, two mounted in each hull. Minimus 11 has been mentioned several times before on this thread as it is an interesting design and build. This item is about its first planned cruise and the outcome.

The first trip was intended to be from California to the warmth of Mexico. Minimus was trailed from Oregon assembled (like a Tiki 26) and launched at Oceanside harbor, California. The trip ended only 250 miles down the coast with “issue of boat and humans”. They stopped due to strong winds and or cold conditions and beam lashing issues. From here I will do an edited quote of the owner builder:

Minimus II's strong points:
--Self steering ability: This is primarily due to the rig. During the 100+ mile sail from Oceanside to Ensenada, where we had light but steady winds, she self steered most of the way, generally broad reaching and downwind.
--Motion: On the second leg, from Ensenada to San Quintin Bay the wind varied from light and variable to calm. Despite often not having wind, the motion was easy and absent the usual slatting of sails I've too often experienced in similar conditions on a ballasted monohull.
--Large deck space: We were happy with the deck boards as they provided much more solid footing than trampolines or nets I've experienced on other multihulls.

Construction: Her 1/2" ply construction gave a sense of solidity as compared with the 1/4" ply typical of most multihulls her size, including the Wharram Hinemoa I once had.

Rig: The most notable feature of her 4 masted rig is its self steering ability. Because she has 4 masts, each one is small, making stepping them an easy process. A related advantage is the ease of handling her small junk sails. Pearl (65 years old) was completely comfortable with raising and lowering sails, something she never was with the Bermudan rig on the original 27 foot monohull Minimus.

Minimus II, Lessons Learned:
--Assembly and disassembly: Full assembly, including stowage of gear and provisions for extended sailing, requires a couple days. She's best suited for extended sailing in which assembly and disassembly are only occasional tasks. We're always pretty tired by the end of assembly. Disassembly is quicker, but still takes half a day or more.
--Exposure: Her small cabins and lack of covered bridge deck mean that her crew are mostly on deck and exposed to the weather. Going into the trip we knew that she would be a warm weather boat, at least for extended sailing. It was the cold weather we didn't expect. Although the cabins are fine for sleeping and sitting, being confined to them for extended periods led us to refer to them as "coffin cabins". Pearl, being 5'4" tall, found them comfortable, but for me at 6' 2", it was tighter. We slept feet to feet in one hull and there were many times that I banged my head where the end of the cabin meets the deck at the head of each cabin. We'll be foam padding those parts of the cabins before going out again.
--Lashings: The lashings between the hulls and the fore and aft beams loosened up a bit in the course of the trip. We weren't sure why and that was a concern, as we weren't sure whether it would continue. Partly, it may have been due to the pressure of the lashings denting the wood on top of the beams. Upper corner of a main beam showing dents where lashings went over it. Both the fore and aft beams had similar denting, the center beam not as much. Beams were Douglas fir with 3 coats of epoxy. Before going out again, we'll route a larger radius in these areas and further reinforce them with fiberglass. Although I've given thought to replacing the lashings with another fastening method such as ratchet straps or metal fasteners, I'm still interested in giving the lashings another try with the above modification.
--Centerboard support lines: On each side of the centerboard are two dyneema supporting lines that keep the centerboard vertical. These lines were knotted at each end and, as happens with dyneema under load, the knots slipped, allowing the board to angle to the side. Our plan is to instead use eye splices in place of knots and to pre-stretch the lines.

Minimus 11 is a well conceived to be a minimal ocean crossing cat but the lessons learnt are important. The owners are 67 and 65 years of age and have designed and built an easily handled cat capable of ocean crossing. But they needed more comfort to suit their age. It’s not about the boat size but its internal functionality. You need real sitting room, bunks that have length width and headroom, space for a functional galley that can be used in any conditions and a toilet that can also be used in any conditions. This can be achieved in an under 25 foot cat but internal layout has to be mocked up tried and tested prior to building the real thing. Also, the exposure issue is really important. Almost every non racing open bridgedeck cruising cat I know has after a short time some form of protection on the bridgedeck or around a cockpit to minimise sun, wind and spray exposure. Human comfort is paramount to a successful, safe cruise.

Mnimus 11 beam issues are important but is just a function of the development of the cat into an ocean crossing boat. To learn more about the boat and its development please refer to the Web site at: Sailboat Project http://omick.net/adventure/minimus_ii/description/description.html

The jpegs give an idea of the boat.

 

This was to be a simple one about Elementarry and the E 25 Harryproas but due to a question I have been asked it will become more complex covering the hull shape and the build method. Basics first. The Elementarry 25 was 25 x 12.33 foot (with a 10 foot smaller hull) with a weight of 264 to 330 lbs with a payload capability 350 lbs. The schooner rig carries a sail area is 225 square foot. The draft varies between 0.35 to 3.35 foot over the daggerboard rudders. The construction could be strip plank Western Red Cedar, flat panel foam glass or Intelligent Infusion. The resulting build weight varies according to the construction method. Strip plank building time is about 300 to 400 hours. The resin infused methods build take between 150 to 200 hours according to the designer.

Rob Denny continuously develops his designs so the next version of the 25 foot Harryproa is called E-25 which is 25 x 13.35 foot with a 15 foot smaller hull. The weight is 310 lbs with a payload capability of 350 lbs. The schooner rig carries a sail area is 236 square foot. The draft 0.2 to 3.35 over the daggerboard rudders. The construction is Intelligent Infusion with a build time of about 150 to 200 hours.

Rob Denny has developed his hull shapes over time whilst also looking at improved build methods. Rob in his initial Harryproa builds used bendy ply which was great for a round bilge shape but not good for inducing rocker in hull shapes. After sailing the first Harry Rob understood that a shunting hull did not require any or minimal rocker. Next Rob starting to put higher prismatic coefficients into his hull shapes. The full ends helped minimise pitching and the higher prismatic coefficient hulls had less resistance when sailing at higher speed length ratio’s. This all added up to better performance. A monohull has prismatic coefficients of 0.5 to about 0.6, normal multihulls have prismatic coefficients of 0.55 to about 0.65 and Harryproas started with prismatic coefficients of about 0.6 but now are as high as 0.75.

At the same time Rob improved his build techniques eventually developing Intelligent Infusion. The Harryproa hull shape with minimal rocker and very high prismatic coefficents has one big advantage. A very simple hull shape can be a fast hull shape in a proa. The length to beam ratios of the latest Harryproas is 16 to 1 to about 19 to 1 on the longer hull, again a very easy shape to build. Result the mould for a Harryproa can literally be a chipboard box with a filler corner trowelled in to form a soft chine. You can do a female mould for a E-25 hull can be made in a day, finalised and waxed the next day and be ready to pull the first hull half on the third day. Intelligent Infusion is a fast build technique that suits the Harryproa hull shape. If you are going to build a catamaran hull the hull shape will be more complex, require a more complex hull mould even if it has a chine shape. Again, I emphasis that Harryproa’s hull shape allow an easy build approach with very simple female moulds, more complex EG catamaran hull shapes increase the build time for a similar length of boat.

More on Harryproa's tomorrow as this is getting to long.

The jpegs give some idea of the build and shapes. The original Harry is the first jpeg.

 

Sailing Harryproas come in many sizes from 25 to 80 foot. Many sizes have been built but the one that impressed me the most is the EX 40 which is 40 x 20 foot which weighs 1,760 lbs and can carry a payload of 1,760 lbs. The schooner rig has two 40 foot carbon fibre masts that carries 645 square foot of sail in 2 square top mainsails. The windward hull is 27 foot long and carries the majority of the accommodation. The length to beam on the leeward hull is at least 18 to 1. The draft varies between 200 mm and 3.8 foot with the dagger rudders fully down. The rudders have a kickup facility if required.

Now we get to a tricky part. There is a second Harryproa 40 footer called AIR 40. The AIR 40 has a different accommodation layout but is basically the same as the EX 40. The AIR 40 has a raiseable roof over the galley and seating area. I have shown the jpegs of the design as they reveal a little more about the basic hull and rig concept. Also the AIR 40 had an interesting folding beam concept if required. I don’t know if this is a “current” design but I think Rob would accommodate a request if it suits your need.

The EX 40 has a practical accommodation layout for 2 people cruising or 4 for a week or 6 for a weekend if you put 2 berths in the mast hull. Your cruising limitation is not space but the amount of payload you can take. 2 people there personal gear, 200 lbs of food, 200 litres of water, 50 litres of fuel, a few toys is already about 1,200 lbs of payload. You have to want to travel light and simple.

The reward is a boat that can travel at windspeed up to about 15 knots of windspeed when reaching and running. Look at it this way. You get the accommodation of a 32 foot Farrier in a cheaper, simpler to build package and get a boat that can match or exceed a Farriers performance with less sailing effort. No spinnakers or screechers required.

The real advantage of proa’s, (if they are correctly designed), be they Pacific, Atlantic or Harryproa’s, is they are light for their length, they have fine hulls, they can carry moderate rigs, still have reasonable accommodation and they perform very well for their size. Anyone who still has doubts about a proa’s safety need only look up Russel Brown’s designed and built Jzerro’s travels. Jzerro, a Pacific proa, has crossed the Pacific and recently under its new owner Ryan Finn has just completed a 12,000 mile single handed non stop trip from New York to San Francisco around Cape Horn. Any boat that can make it around Cape Horn in rough conditions deserves respect and further investigation. There are many “famous” production catamarans I would not try that trip in.

The ease of build of a Harryproa and its performance are the real reason I am attracted to the concept but also, I have learnt you do not need to bring your land lifestyle sailing with you. As Tony Grainger said to me “all you need is a well built boat, some spare rope, a second compass with a bit extra food and water and you should be able to sail anywhere.”

The construction of the EX 40 is foam glass using intelligent Infusion moulds and flat panels. The composite materials list for hulls, beams, masts, rudders and booms, ex wastage which varies from 0-10% depending on material and usage:

400 gsm double bias glass: 310 sq m; 400 uni glass: 28 sq m; 300 carbon uni: 89 kgs; Peel ply: 154 sq m

12mm H80 foam: 112 sq m; 8mm H80 foam: 4 sq m

Infusion resin: 327 kgs; Glue and bog powder: 1 kg of each

The jpegs are of the EX 40 first then the AIR 40.

 

Unfortunately Jzerro didn’t make it non stop as they had to stop for repairs on the way down.
Legendary voyage none the less.

 

Reality disconnect. Designers Pieter van Geest and Rob Doyle have conceived the Domus concept, a 40 meter luxury trimaran with the majority of the accommodation on 1 level. The Domus 40 is a 131 x 115 foot trimaran that displaces about 200,000 lbs. The Domus is listed as having a Gross Tonnage of 750 tons, that does not mean it displaces 750 tons. Gross tonnage is old fashion way (1800’s) of assessing displacement based on a few things like length, width and freeboard height. People were then taxed on the gross tonnage. The modern issue is safety regulations, navigation rules etc were based on gross tonnage with a “magic” number of 500 tons. Over about 500 gross tons requires a lot of safety equipment, firefighting stuff, lockable steel doors, separate watertight bulkheads, electronic reporting AIS, radar, annual inspections, certification for insurance etc. This can be a multimillion dollar impost on a design and build.

The rig has a 97 foot wing mast that carries a 4400 square foot mainsail and a 2460 square foot foretriangle. The length to beam on the mainhull is 10 to 1 and the floats are 20 to 1. The draft is unknown but assume 8 foot plus. The power is hybrid that uniquely combination a vast array of Solar power, Hydro Regeneration & Hydrogen Fuel cells giving Domus unlimited range with Zero Emissions. The optimised system of Solar Power and Battery Storage, allows the yacht to motor during daylight hours and then transfer over to the Battery system at night. This also means that Domus is fully silent with Zero Emissions while at anchor as there is no generator noise and exhaust emissions.

Being a trimaran, it has one major advantage, it only requires a single “engine” room and battery storage area etc reducing the need to duplicate everything as would happen in a catamaran. Also, the structural loads can be reduced by having the mast on the mainhull not on a cross beam structure between 2 hulls. This simplifies the design and total structure but it is only a marginal gain. A 115 foot beam requires real engineering and the rig with stays going out to the edges again is puts strains across a total structure, not just on the mainhull. There is no mention of the build materials but I would imagine foam glass with a lot of carbon or very well engineered aluminium.

The accommodation is vast and is the equivalent to a 260 foot monohull. The designers studied what would be the smallest size vessel they could design with the 1 floor layout without making it look too bulky. While RDD has been focussing on the naval architecture, performance, and structural feasibilities VGD developed the styling and layouts. Domus is an amalgamation of ideas that were discussed daily over the development period. There are vast cabins for the owners and guests with crew having their own completely separated quarters and their own galley seating area etc. on a lower deck in the main hull. There is sufficient space to allow a completely covered cockpit area aft that is 135 foot wide and from 10 to 30 foot deep. Your internal fabrics, entertainment and furniture will probably cost a million dollars. The tri is designed not to heel any more than 2 degrees when sailing to suit the “older clientele” that are likely to be able to afford such luxury.

The yacht has its control cockpits in the floats and main hull roof top. There would be power winches galore and a lot of push button controls etc. This tri would be easy to sail as long as you had a full time electronics and mechanical engineer on board to keep everything running.

So, this is your dream boat and you have a big enough back yard to build it. It could be done with a lot of flat panels, a 50 ton crane mobile crane, a giant build shed, 100,000 plus man hours and maybe $50 million. Are, next weeks Lotto win should cover it? I need to reconnect with reality. The jpegs give the idea.

 

Catmaris is a manufacturer of aluminium custom catamarans based around a few basic models. The cat chosen is a 64 x 31.4 foot with a weight of 98,000 lbs and a load capacity of 15,000 lbs. The 77 foot fixed aluminium mast carries a 1100 square foot genoa, 1500 square foot screecher and a 1000 square foot in mast roller furling main. The hull length to beam of the hulls is about 9 to 1. The draft is 5 foot over low aspect ratio keels. Engines are Volvo Diesel D 4 (latest version) 2 x 160 hp. Options are stronger engines or electric "Green Power Supply" hybrid system. Economy cruise 8 knots, cruise 10 knots and a maximum of 12 knots.

Catmaris cats are designed for EG passing through the NW passage, sailing expeditions in the Antarctic or island hopping in the Caribbean. In short, they are designed and built strongly as is reflected by the 98,000 lbs weight.

The accommodation can be anything you want with a total living and usable area 205 sqm: Exterior 109 sqm, interior 96 sqm. A basic layout would be 3 double berth cabins with attached toilets and a smaller skipper’s cabin with its own toilet. There is one version with a vast owner’s cabin forward of the main beam for those who want the ultimate comfort. The advantage of custom internal builds is they can meet special request such as a wheelchair friendly layout. Also the weight of 98,000 lbs should give the hint that you can have a luxury fitout with any furniture, appliances and toys you want. The main saloon and lower cockpit allow a very large galley and lounging space. The flybridge can be small or very large with all controls leading back to the flybridge. There is an internal navigation and steering area. There is a roller furling forestay and mainsail which allows you to have a warm time whilst sailing by push button.

The cat is a very well built structure with 5083 H 321/H111 aluminium that is certified by "Germanischer Lloyd, Bureau Veritas or Lloyd's Register". 5083 has the best resistance to corrosion and seawater. The designer of the 64 footer is Marc Lombard, a designer who really knows multihulls and what is required to achieve fast strong multihulls. The builder is Catmarais, a German based company that outsources its builds to "Dijkstra Jachtbouw" in Harlingen (Holland), founded in 2003. Dijkstra is highly specialized in aluminium and certified by "Germanischer Lloyd" and "Bureau Veritas".

The jpegs give the idea of a very well designed and built cruising cat.

 

Part 2 of Catmarais build jpegs

 

Be warned you are going to feel bad as you read this because you are going to feel inadequate, don’t worry, this is the third guy I know who has achieved an amazing boat building outcome. Read on you may be the fourth.

I said I would get back to reality, so we will discuss a home designed and built aluminum power. Clyde was a rancher and sold his business and wanted something to do. In 1989 Clyde moved inland 85 miles out of San Diego where there is some open space, drew up some basic plans of a power cat, built a model and floated tested it. It floated on its lines and when towed had good characteristics. So, Clyde, who has good welding skills and a strong work ethic, decided to go ahead. 5 years later the aluminum power cat was launched in 1994 after a lot of working alone with occasional help from a friend. Good so far.

So to start he laid down the 100 foot long building pad to place a few temporary wooden frames to check the build shape and confirm stringer positions. Huh 100 foot build pad!!! Oh, I forgot to mention the cat’s size. Clyde built, almost single handed, a 100 x 40 foot aluminum full wingdeck power cruising catamaran. The other dimensions are unknown but a guess would be a displacement of about 180,000 lbs and a length to beam of about 12 to 1. A draft of about 5 foot with propellers in tunnels in the stern. The 2 engines are 340 V6 diesels that drive it at cruising speed of 9.2 knots. Having propellers 31 foot apart allows maximum mouverability in tight marinas.

Back to the build, first build your 8 x 10 foot aluminum building frame from 160 x 12 mm plate and put 30 V shape notches around the edge, drill 30 holes in the frame to lighten it a bit. Now you move the about 200 lbs frame into position and start on the next frame. After 70 plus frames you have the shape of 2 hulls. Next you put on the hull 30 plus 100 foot long 50 x 50 mm L shape stringers at 300 mm centrelines. Simple so far, next you put on 5 x 20 foot 4.8 mm thick 267 lbs aluminum sheets on the outside and weld the skins to the hull frames. Now remember this cat is being built in the desert 85 miles inland where it gets a little hot. Clyde did a lot of welding at night to minimise his and the aluminum heat distortion. PS this means doing 12 to 14 hour days for 5 years.

Next came the wing deck structure. The underwing has the same build structure as the hull on the top and bottom of 300 mm beams. At one point Clyde was crawling and welding inside the 300 mm gap between the top and bottom skins. Once the underwing was built the deck cabins were built. Now we have the shape of the cat complete there was the minor detail of getting a smooth finish on the outside. After putting a chemical surface cleaner over the entire exterior, Clyde put a 4 to 6 mm layer of Bondo filler on the outside of the cat and start fairing the 14,000 plus square foot. After a very short time Clyde developed 4 different sanding machines to assist him doing the fairing. He in effect had a power assisted long board. Are success! Now we had a good looking structurally sound shell with engines installed. After 5 years of work now all Clyde had to do was shift the cat 85 miles to the water.

Small problem you cannot shift a 40 foot wide cat down normal roads. No problem to Clyde. Just cut the cat up into 7 pieces to move the cat. It only took a couple of days to cut the wing deck cabin structure off the hulls into transportable components. Hire your massive mobile crane, 7 big semi trailers and move the whole lot to a marina in San Diego. Now on the same day float the 2 individual hulls on the water (each hull stayed upright without support) then crane on to the hulls (which were floating in position) the first of 5 bridgedeck parts. Then crane on the next part etc. Finish the job at 6 pm on the same day you left your build plot 85 miles away. A few days later all the major cut lines were welded up and final finishing of the structure and other basic installations took anther 4 months at the dock.

About now I am not only amazed but in awe of Clyde’s work ethic, building skill and most importantly his organizational and planning skills. This is a massive undertaking that took 20,000 plus person hours to have a viable in the water sailing shell. The cat sat in the marina for another 6 months having a basic internal fitout before motoring to another marina for the final basic fitout in ply and chipboard etc. After that “Kalelidoscope” went on a cruise to Mexico then through the Panama Canal to the West Indies and Florida before being sold to a couple about 3 years ago for charter work. If you have 30 to 150 people you can do a nice day cruise on the cat.

All to unbelievable for you, head to Youtube and type into the search function the following: WORLDS LARGEST Homemade backyard boat, yacht build by one man from concept to completion in 5 years

There are 7 video’s showing the build, transport and travels. Also, there is a video of the boat for charter. The jpegs are nothing compared to the videos.

 

The Vision 444 is a South African built James Turner designed composite cruising catamaran. The Vision 444 is 44.3 x 25 foot with a weight of 20,160 lbs and a displacement of 25,760 lbs. The fixed aluminium mast is 62 foot high, carries a 720 square foot mainsail and a 313 square foot self tacking jib. There is optional screechers and spinnakers. The hull length to beam is about 7.7 to 1. The draft over the fixed low aspect ratio keel is 3.8 foot. The underwing clearance is 2.3 foot. The engines are 2 X 38HP Nanni Diesels with 24V 75amp house bank charging alternator and 12V 120amp Alternator starter battery charging.

The accommodation 4 double berth cabinets with attached toilets in the hulls. The engines are under the aft berths which have a thick insulation layer under the mattress’s. The main saloon contains the galley, dinette, seating and navigation with a large opening to the cockpit allowing an integrated space. The steering “cockpit” is a step up from the cockpit allowing access to all ropes required to control the rig and sails. This cat has a well thought out and practical layout for real cruising for 4 people. There is sufficient storage and external lockers to carry the additional stuff that one brings cruising.

Performance is not mentioned but the load carrying hulls with moderate sized rig indicates an 8 – 10 knot average type of cruising cat with peaks around 18 knots.

The structure of the cat is vacuum resin infused Crystic Vinylester resin used throughout with e-glass and foam core. The moulds have Crystic Spray Gelcoats sprayed on first before the vacuum infusion. Foam glass sandwich furniture is structurally bonded to the hull shell. The composite rudders are on 60.3mm Stainless Steel rudder shafts with a solid section at the through hull point. Through hull Acetyl rudder bushes are on the rudder shafts. Tie bar connected steering with vectran or cable system to a composite steering wheel. The Vision 444 has a state-of-the-art 24v DC system which is as easy to maintain as it is to understand. The lightweight installation has convenient access points throughout the yacht which enables you to identify the source of any electrical problem, in the unlikely event you ever have one. The system is simple and effective, and you don’t need an electrical degree to keep it in perfect order.

The jpegs give the idea, full production will start later in 2022 but 7 are already in the water.

 

Seven Sisters was a very unusual design in that she had a main hull like a monohull, but with two wave-piercing floats, thus the 'hybrid' name. The catamaran or trimaran was 40 x about 20 foot with a small rig thast has a Nacra 5.5 loose footed mainsail, a jib and a spinnaker. The boat was built by 2 brothers in 1998 in Hawaii, and is equipped with three propulsion sources: Sails, a 10 KW solar panel powered electric motor, and a high efficiency 70 HP outboard engine, capable of generating 15-17 knots, with virtually no wake. The electric motor was placed onto an outboard that originally had 115 HP engine. Under sail the boat cold sail at 7 – 8 knots downwind.

Seven sisters travelled the seas for 16 years until it visited in Costa Rica last April 2014 where many items were stolen including batteries, a 70-hp outboard engine, refrigeration components, and even the steering wheel. The owner decided to single handed back to return to California for repairs to the boat “He was sailing directly for Cabo San Lucas but would have no way to get weather forecasts for the Tehuantepec, which is blowing most of the time at this time of year. From his last reported position, he was 100 miles south of Huatulco on the edge of the Tehuantepec winds and seas. Our guess is that the boat could not handle the waves and turtled." There were many signs that he had been trying to survive atop the overturned hull and in one jpeg you will see a mattress and sail sunshade set up on the upturn main hull. The owner was never found.

The boat was built in foam glass to a “home design” to try many new ideas. I have deep sympathy for all people associated with this vessel but a few comments. This vessel was ahead of its time with an electric auxiliary motor “powered” by a small solar array of low powered panels. The battery bank would have been limited. The sails were the main motive power during sea passages.

The design has a narrow main hull bow widening into a very flat wide monohull type stern. In light conditions and a light load there would have been minimal wetted surface but the when there is an overload and or any wave conditions it pick up a large amount of wetted surface. This is not a logical design model. The wave piercing floats are OK when motoring but have a major issues when under sail. Low buoyancy floats are not good in heavy seas. The fat aft on the main hull would probably help stability. Again, not really logical. Now, we get to my real issue, although this boat had travelled the seas for 16 years there was some form of structural failure. If the boat hit something with a float bow I would expect a broken bow but if you study the jpegs you will find the bow and stern of one wave piercing hull broken off at the crossbeam connection. The actual crossbeam web bulkhead that goes into the hull was broken in half and looks like a timber structure. This could be a maintenance problem or a design failure in rough seas.

Message from this, please understand sailing offshore is risky. Do not go out single handed into rough conditions (time of year) in an ill prepared boat (due to theft of items). Do yearly checks on your entire vessel, do not assume because your boat has sailed for years it will be OK. All boats deteriorate over time, I had a 50 foot mast crash down 6 foot from me just after the owner assured me the rig could take the strong winds. Finally, this design is original and ahead of its time BUT it is not a logical design. It configuration is a half breed neither a good wave piercing catamaran nor a good sailing trimaran, it has good accommodation, interesting powering options and a small auxiliary rig. Do not be to inspired by this concept as there are better options.

 

A gifted trimaran maintenance worker, David Reard decided to design and build his own trimaran. The tri he built was a Bebox 333 design that is 32.5 x 27.7 foot with a weight 6160 lbs. The 46 foot fixed aluminium mast carries a sail area in the mainsail is 516 square foot, a self-tacking jib of 290 square foot, a gennaker of 540 square foot and an asymmetric spinnaker of 1022 square foot on a furler. The floats are very high buoyancy. The draft is 2 foot to 7 foot over the daggerboard. The engine is a 15 hp outboard.

A small detail. The numbers above are a combination of 3 Bebox 333 tri’s for sale (there was only meant to be 2 built but you will 3 tris in the jpegs). Each have slightly different rigs and displacement figures. The builds also vary slightly.

The accommodation is 1 double berth at the rear, 1 single berth forward, 2 berths in the saloon with a folding saloon table. Cold water foot pump in the kitchen, Stainless steel sink and a Gas cooker with 2 stainless steel burners. It has 6.5 foot headroom. This is an effective minimalist accommodation layout for a high performance trimaran. The reported performance is peaks of 19 to 20 knots with 10 knot averages possible on the fixed aluminum mast version. There is one with a carbon rotating mast which has a slightly larger rig which may go faster.

The build of this tri, as best I can understand, is for the main hull strip plank e-glass and carbon in epoxy below the waterline, plywood sides and decks with timber framing and stringers glassed on the outside. The floats are Airex Epoxy infused. The cross arms are in Strip Planking with carbon fibre in epoxy in one of the tri’s. There appears to be composite cross arms on another of the tri’s. The built dates vary between 2003 and 2007 of the 3 boats.

An interesting design that would form a very nice cruiser racer. The jpegs give the idea.

 

The interior of that boat seems to work very well. it would be interesting to see sections of the main hull. The interior shots make the hull look quite wide.

 

Russell. The closest information I have is a few additional jpegs. The main hull appears to be 8.2 foot at its widest point on deck with a waterline width of about 4.7 foot (scaled from jpegs so a educated guess). David Reard has a facebook site at: Log into Facebook https://www.facebook.com/archireard A contact for him maybe:
davidreard@gmail.com If anyone else can help, please do so.

 

So it's the really wide, shallow underbody that makes the interior work so well. I wonder how it sails.
Quite an interesting and simple boat. The ama's don't look simple, but the rest of the boat looks easy to build and affordable.