Multihull Structure Thoughts

I believe that was the only Trice 3 built. She was built by a friend of mine in New York in the early 80’s. A very experienced multihuller.

 

The Trice 3 is a interesting boat, if you talk to your friend ask if he would share more about it. To be accurate it is has a stern cockpit with the small stern cabin seen on some Newicks.

 

A short one about the way New Zealanders have a can-do attitude. The jpegs below are real. A 65 foot “trailer sailor” hull. The guy is moving his part built 65 foot cat. Yes, the cylinder molded 65 foot cat is moving closer to the ocean indeed. Chris notes: “Just moving my “project” from Eureka, 75km closer to the ocean at Turua which is only 5kms from Kopu (Coromandel Peninsula) where I can reassemble and launch.”

The catamaran is a Kurt Hughes design that has been used as a cruiser and/or a charter cat. The cat is 65 x 36 foot with a weight of 28,600 lbs and a displacement of 47,600 lbs. The 75 foot mast is either an aluminium tube or wing mast that carries a 1,134 square foot mainsail, a 464 square foot jib, a 1,099 square foot screecher and a 1,250 square foot spinnaker. The length to beam is about 12 to 1. The underwing clearance is 3.9 foot. The design is optimized for short-handed sailing.

The accommodation is vast. There are 6 double berth cabins and 2 single berth cabins with 3 bathrooms is the hulls. The main saloon has seats and tables plus a full size galley and an entertainment navigation area. All this can be customised to suit your needs as long as the bulkhead structure remain in the same positions.

The first 65' bridgedeck cruising catamaran was built of CM epoxy/plywood in the hulls and plywood and timber in New Zealand and others have been built in the foam/glass.

These cats are very large builds and require a lot of money but some people do amazing things as you see in some of the jpegs.

 

Hughes “Bread Box” for sale in the PNW…

New to Market! Hughes 34 Trimaran - boats - by dealer - marine sale - craigslist https://seattle.craigslist.org/sno/bod/d/everett-new-to-market-hughes-34-trimaran/7667807349.html

 

Unfortunately there are packing crate elements in that build/fit out. I was wondering if angle iron was under the paint on some of that hardware or is it home store aluminum? Price to build quality might involve deducting some zeros.

 

I must say that I’m not impressed by the boat. Not even a little bit. Did Hughes really design those cross beams, rudders and daggerboard? I seriously doubt it. The interior is very agricultural. As is most of the exterior. …which is all fine if that’s what you want but for the asking price??? Sheesh, Carter can’t get 40 for his beautiful Chris White and I had no serious interest in my Newick at 25. Crazy.

 

This is an interesting piece of research that may be appropriate to smaller multihulls. Large power trimarans have a design problem of how low you can have the bridge deck hiegth versus the slamming loads that happen on the wing deck. The attached piece if research tried to quantify those slamming loads versus bridge deck heights.

A short summary: The higher the bridge deck of the water the lower the slamming loads, the slower the vessel the lower the slamming loads. The surprise was attach a 2 mm thick silica gel plates attached to the water side of the bridge deck, the slamming-pressure coefficient decreased by around 75–80%.

The 6 meg study can be downloaded from: Impact Force Mechanism of a Trimaran Model and Its Experimental Validation https://www.mdpi.com/2076-3417/13/18/10382

The following is the conclusion from the study.

This article aims to find a possible way to reduce the slamming pressure, in order to improve the safety of trimarans during navigation. In the model shown in Figure 1, the data measured for the two pairs of symmetrical measuring points on the outer connection bridges are large. On the contrary, the data measured for the two other pairs of symmetrical measuring points on the inner connection bridges are small. As the height changed, the slamming-pressure coefficient changed in a similar way. With an increase in the drop height, the slamming-pressure coefficient dropped slightly. The falling speed of the model decreased rapidly due to the force from the water. This was the most prominent after the slamming force reached its peak.

When flexible claddings of 1 mm, 2 mm, or 4 mm thick silica gel plate were coated on the model, it was obvious that they could reduce the slamming force significantly, especially when there was air between the model and the flexible cladding. Meanwhile, a thicker surface of flexible cladding could reduce the force more significantly. However, this led to a blunt effect. In the same working conditions, when the thickness was increased from 1 mm to 4 mm, the change in the measured slamming pressure was small. When the thickness was increased from 0 mm to 2 mm, the slamming-pressure coefficient decreased by around 75–80%. However, from 0 mm to 4 mm, it only decreased by around 80–90%. The thickness increased a lot, but the effect did not actually improve much.

The results from the force model and the main hull’s force-prediction model are in close agreement with those obtained from the experiment. Thus, our experiment confirms that the theoretical model is effective. For the same working conditions, the model with flexible cladding will reduce the pressure by nearly 50%. And our experiment validates that it is possible to reduce the slamming pressure of the trimaran to improve security by using flexible cladding.

The jpeg is from the study.

 

A short one for those who like the environment.
Genetically modified silkworms producing silk stronger than Kevlar in China.
Scientists in China say they have been able to genetically modify silkworms to spin silk fibres six times stronger than the material used to make bulletproof vests. The secret? Spider silk. "Silkworm silk is presently the only animal silk fibre commercialised on a large scale, with well-established rearing techniques," Junpeng Mi, a PhD candidate at the College of Biological Science and Medical Engineering at Donghua University, Shanghai, and the first author of the study published in the journal Matter today, said. "Consequently, employing genetically modified silkworms to produce spider silk fibre enables low-cost, large-scale commercialisation."
Spider silk is far stronger than silk naturally produced by silkworms. To spin spider silk from silkworms, Mi and his team introduced spider silk protein genes into the DNA of silkworms so that it would be expressed in their glands, using a combination of gene editing technology and hundreds of thousands of microinjections into fertilised silkworm eggs.
The spider silk fibres could also be used to create more comfortable garments and innovative types of bulletproof vests, Mi said, and they may have applications in smart materials, the military, aerospace technology, and biomedical engineering.
"We are confident that large-scale commercialization is on the horizon," he said.

 

This is about a trimaran and one mans determination to keep it sailing at all costs. In 1978 Olympus Photo sailed by Mike Birch finished just 98 seconds ahead of his nearest rival Michel Malinovsky’s mighty 70 foot monohull yacht Kriter V in the first Route Du Rum, after being several miles behind 20 miles from the finish. Mike Birch became a French national hero. This race put multihulls on the sailing map. There were 5 version of the Walter Greene designed Olympus Photo trimaran built, sailed and raced. We will focus on the 1981 build of ACAPELLA built for Charlie CAPELLE.

Why? Acapella has completed 8 Route Du Rums since 1982 and been wrecked and rebuilt 3 times. First wreck was after a collision in Brittany in 1998 and rebuilt by Charlie then wrecked in Canada and disappeared until discovered in Spain in 2006 and restored by Charlie. In 2009 Acapella capsized then was restored by Charlie prior to the start of the 2010 Route Du Rum. That is serious dedication to a boat. The last Route Du Rum Acapella raced was in 2022 and has finished as high as 3 rd in class. Acapella has won many other races in the interim.

Acapella originally was 36 x 25.8 foot with a weight of 5,600 lbs. The current versions after rebuilds is 39 x 27 foot with a sailing displacement of 8.280 lbs. The original rig has an aluminium mast of 55 foot, the latest version has a rotating carbon fibre mast of 55 foot. The mainsail is 538 square foot, the solent is 355 square foot, the staysail is 193 square foot and a 970 square foot spinnaker. The latest version has a 13 HP Volvo inboard diesel.

The accommodation is considered good for a modern racer but still still only has 2 single berths with some space for a galley and navigation etc. Acapella is not a cruiser but as a fast racer does very well.

Now we get to the build. We have a problem of variations over time. The original was a molded ply wood epoxy mainhull and crossbeams with plywood bulkheads and timber stringers. The floats were polyester e-glass foam sandwich which in 1981 was Walter Greene’s approach to trimarans float design. In later rebuilds I suspect the floats were done in vinylester or epoxy resin glass on foam. I also suspect the cross beams were modified to allow the wider beam. The tri was also put on a diet at one point with eg a carbon fibre mast and synthetic rigging with a carbon fibre mainsail.

Acapella is a famous tri in France as is Charlie Capelle. He is in his 70’s and is still in love with his tri. A very dedicated man who deserves respect. The jpeg are of the tri at various stages of sailing and rebuilds. The line plans are of the recent 39 foot version. A great boat.

 

This is about 2 racing tris that used the same hull moulds but were built 3 years apart. The first tri was built in 2020 and was named Planet Warriors then Ciela Village then Koesio and has sailed in many races including winning the 2022 Route du Rhum in the livery of Koesio. The second tri was built in 2023 and sails under the name of Réalité another Ocean Fifty built in the same moulds as Planet Warrior. These 2 tris are the same length and beam of 50 x 50 foot with a weight of 7200 lbs. The draft of both over the central daggerboard and float based C foils is 11.5 foot. The difference is in the rig. The 2020 design has a 67 foot rotating carbon wing mast with an upwind sail area of 1,904 square foot and a downwind sail are of 2,850 square foot. The 2023 design has a 73 foot rotating carbon fibre wing mast with an upwind sail area of 1,936 square foot and a down wind sail area of 2,900 square foot. The power to weight of these single-handed racing tris is amazing. And before you ask these tris can average 20 knots and peak at over 30 knots.

Now to the main point of this post. VPLP started with tools to allow them try out loads of configurations with the aim of optimizing weight. Weight-saving efforts also included the static parts of the boat, such as the fittings, the engine, the lines, the pipework and the wiring. As a result, Ciela Village is the lightest boat in the Ocean Fifty fleet. Next came the hull shapes, VPLP drew on feedback relating to foiling behaviour from the two previous Ocean Fifties designed by the firm (Solidaires en Peloton-ARSEP and Ciela Village, now Leyton), thus turning the research dial significantly towards enhancing performance. In practical terms, a lot of work was done on the longitudinal centres of volume, moving them aft to stop the boat from porpoising too much because of the lack of foiling surfaces in the stern.

Another innovation involved the K-shaped set-up of the beams, with the after beam extending to the foot of the mast. This freed up space so the cockpit could be twice as long and entirely shielded with plenty of room under the canopy. This has been a huge improvement for the skipper’s protection out on the ocean, but also for the Grands Prix because weight could be centred, the winches and other gear having been moved forward. “As a result, the crew are further forward, giving the boat a better trim overall,” said VPLP.

The 2023 Réalité features some innovations in terms of ergonomics and structure to ensure that she is easier to sail and more powerful, without exceeding the minimum weight required by the class rules. This means greater protection in the stern and a stiffer structure, making her more responsive. The cockpit has been entirely reworked to give the crew a dedicated handling and living area above deck which is comprehensively sheltered from the elements but nevertheless provides great outward visibility.

A comment from the Route Du Rum Ocean 50 skippers “The skippers talked about it at the finishing line. It’s obvious that, given the level of commitment and the intense pace, particularly in the first week, those who were better protected from the elements were able to maintain higher average speeds.”

A lot of work was also done on her aerodynamics with a view to reducing as much as possible air resistance, a factor that is becoming increasingly problematic for these boats which are sailing faster than ever.

The structure of these 2 tris are basically carbon fibre epoxy over foam with some fiberglass in secondary areas. The structural design is a combination of FEA analysis and pure design experience based on many years of racing designs. The builder is CDK Technologies in both tris.

The jpegs give an idea.

 

thanks again old multi...
if anyone has any photo's of realities (above) cockpit arrangement I would love to see them.
thank you.

 

Peterbike. Realities was also named Leyton Realities. There is a Youtube video of it doing 33 knots on the web. Here is a few shots of the cockpit area. The Realities sailing team has a facebook page as well.

 

Baltic produce very high quality monohull fast cruising yachts. They are a direct competitor to Swan yachts. Baltic yachts don’t talk to the common person, if you want a 50 foot to 170 foot yacht talk to Baltic and say how fast you want it to sail. Your carbon wonder monohull will be delivered in a year or so. So here comes your usual Baltic buyer. I want a fast day sailing yacht that I can cruise in occasionally. Garth Brewer the owners project manager said “The boat is primarily for pure enjoyment and the owner likes the challenge of doing something that hasn’t been done before. He really understands the technical elements and this will be a development project which will require a measured approach.” OK how fast? America cup fast and I don’t care what it costs Baltic gets to work.

Result: Raven a 111.5 x 24.25 foot monohull that has a light displacement of 121,000 lbs. The draft is 15.75 foot with a 20,500 lbs bulb at the bottom of the keel. Raven will be powered by twin Yanmar generators and a Swiss Phi-Power AG electric propulsion motor. The drive train is completed by a retractable propeller designed with carbon blades and a titanium hub. Nothing really outstanding so far, beyond a relatively low ballast ratio, for a boat that has already been launched. It the next phase of the build that is really Interesting.

America Cup type T foils that can be rotated outward from the hull sides to add stability and provide lift. The sail plan and rig is relatively conventional, with a Southern Spars carbon mast and North Sails 3Di headsails using Helix structured luff technology, plus a full complement of Code and asymmetric sails set from an 8m bowsprit.

This foil-assisted, ultra-lightweight superyacht will break new ground and Baltic says it is “one of the most extreme yachts” it has built in its 50-year history. Raven is designed to sail partly on her leeward chine, with giant T-foils providing the bulk of stability, plus some vertical lift, while a 9.3-tonne bulb at the end of a precision engineered 5m-deep fixed fin keel provides additional righting moment. The T-foils are mounted on hydraulically operated arms capable of supporting a sizeable proportion of the boat’s displacement, while fore and aft trim is controlled by vertical trim tabs at the transom. In addition, water ballast tanks in each aft quarter provide a further boost to righting moment when necessary.

Raven’s speed potential will be similar to a multihull. The apparent wind will be so far forward, even when the true wind is well aft of the beam, that the mainsail is expected to be permanently sheeted home, with minor trim adjustments made using the traveller in exactly the same fashion as MOD70 and Ultime trimarans. Raven’s potential performance data is subject to a confidentiality agreement, but it’s clear this yacht is one that has potential to break many records, including the 24-hour monohull distance record of 641.13 miles in 24 hours set by Team Malizia in The Ocean Race.

The construction is very weight sensitive. The boat is carbon fibre epoxy foam sandwich everywhere but the detailed weight study found weight savings throughout. EG lightweight seat fabrics, internal furniture, reduced lengths of lightweight internal piping and electric runs, lightweight deck gear, minimizing of sound proofing with the owner accepting this is going to be a noisy yacht when foiling etc. Raven’s weight savings extends to the shower doors, which have been reduced from 13.5kg-per-metres-square to just 2.3kg-per-metres-square. The result of all the weight saving is this 111 foot monohull is half the weight of similar sized monohulls.

Accommodation will be for four guests across two cabins, plus an owner’s cabin aft that includes a large double centreline berth that folds up against the interior bulkhead when racing. Jarkko Jämsén opted for a distinctive, industrial aesthetic for the interiors, featuring minimalist, but most importantly lightweight, rattan deckhands alongside exposed carbon.

The owner expects Raven will take from its launch, 2 years to develop and optimize to get to full speed and possible break records. If you can afford the first $100 million plus I suppose another $50 million in development will be a minor detail. Remember this is a daysailor, occasional cruiser for the owner.

 

Marcelo Penna Yacht Design together with Marcelo Penna Engineering, a Spanish design studio had a nice very rich client arrive wanting a support vessel for cruising yacht. He needed to have his 2 helicopters available on call. Result was the Yacht Shadow Vessel 60 (YSV60). The power trimaran is 197 x 68 foot that has a gross tonnage of 1,124 tons (2,517,000 lbs). The engine power is twin Caterpillar engines, with fixed-pitch propellers or waterjets, should permit a 23-knot maximum speed. Furthermore, the YSV60 should see transpacific range, between 4,948 nautical miles and 5,700 nautical miles, depending on conditions. Under power on just one engine, the vessel should achieve more than 7,000 nautical miles.

The YSV60 has significant stowage for spare parts and other goods. Climate control is provided for those areas, too. She can even provide bunkering services for her mothership. Extra crew, personal staff, or guests can stay aboard, in accommodations for 12. Of course, there are also plenty of places for tenders to 36 feet (11 meters), toys, and support craft to stay. They go on deck and in dedicated 2 hangars for the larger helicopters. Possibilities include a DeepFlight personal submarine, several PWCs, and kayaks. The crane in the illustrations here, directly behind the superstructure, can lift and launch the daily preferences. Boarding and disembarking occur either alongside the YSV60 or aft. Marcelo Penna Yacht Design has included opening platforms to make it easier. So why are Marcelo Penna Yacht Design confident about the performance of this design?

Because Marcelo Penna Yacht Design has done this style of power trimaran before. They have designed and had built a MP625 power trimaran designs that seek to compete with helicopters in the long-range crew transfer marketplace for example offshore wind farms. The design can be customised for a range of operational profiles, such as crew and personnel transfer, fast supply, emergency response and rescue, rig evacuation and oil-spill response. The MP625 (210 x 68 foot) is a diesel-direct vessel with four fixed-pitch propellers or four waterjets, according to the customer’s requirements, and two bow thrusters forward, one of them retractable. It is designed to maintain position in a sea state with waves of up to Hs 3.5–4.0 meter (up to 13 foot sea state). The design allows for up to 21 knots of max speed while providing full comfort for personnel and cargo transfers (between 1,000 and 2,000 kg) with up to 3,5m waves, compared to the industry norm of Hs 2.5m.

The message here is that some people are very rich, but more importantly these types of tris are more useful and comfortable than monohull equivalents in a seaway. The tris are also economical and can be designed to travel long distances at reasonable speeds. The first jpegs are of the MP625 blue work boat, The yellow tri is the “private” support vessel.

 

This is about a “lifestyle” trimaran. A trimaran that is about the accommodation space at the cost of all else. Yes, the tri would be able to sail but the engine power will be of great assistance, yes the tri will be stable, yes you will have more than enough accommodation. What you may not have is a comfortable sea motion in a seaway and good top speed under sail due to the very large floats and narrow tunnels between hulls. I sailed on a 48 foot Piver years ago that had similar characteristics (but less extreme) and it was not good in a seaway and going to windward was a struggle. If you want accommodation at all costs and plan to sail in quite waters this is the tri for you. If you plan to cross oceans leave it to the paid crew.

Designed and engineered in Australia, the Custom Trimaran 24m is built “to take on the world” according to the advertising. The “Custom Trimaran” is 78.7 x 52.5 foot of an unknown displacement (guess about 150,000 lbs). The masthead rig 75 foot mast that carries a 970 square foot mainsail and a 970 square foot fore triangle. The length to beam on the main hull and floats is about 7 to 1. The draft is unknown but I would guess low aspect ratio keels with a draft of about 6 foot. The 350kwh electric motor will quietly take you without the need to ever stop for fuel due to the solar panel arrays.

If the sail power to weight ratio and wetted surface to sail area is as I have estimated, the engine power will be used in any winds below 10 knots to get anywhere and I doubt this tri will get above 15 knots boat speed unless it is surfing down a wave. You will be have space and privacy, good views and toys to play with as an offset to the reduced fun under sail. This is not a NEEL trimaran.

The internal space in this design features a huge open plan salon with galley bar formal dining table for 12 with additional seating and entertainment area. There are 6 private queen staterooms with ensuite bathrooms, 2 bunk rooms that each sleep 4 and huge rear deck provide you a very large and comfortable, relaxed and uncluttered Custom Trimaran 24m lifestyle. There is even a “garden” room if you need to get away from the crowd.

The composite construction is of vinyl-ester, fibreglass, carbon fibre, and Kevlar that “will last 2 lifetimes”. I have no question of the structure if it is well designed.

The Custom Trimaran is a pure Motor Sailer cruiser that will provide a very large amount of accommodation for charter or as a cruiser. But I suspect it will need a lot of development in the planned engine power, a large amount of development in fail proof electrical and plumbing services of such a large vessel. If you want a mini floating hotel great, but if you want to cross oceans quickly there are other options.

The jpegs give the idea.