Multihull Structure Thoughts

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

  1. patzefran
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    patzefran patzefran

    "So, you have a very fast cabin cat in the TS5 but speed can have one downside. Hallucine, with 4 crewmembers in November 2020, off La Coruna, Spain struck a partially submerged container at 20 knots and pitch-poled, with one crewmember lost. The 1600 plus lost containers per year if hit at 7 knots would do damage but may not cause a capsize. Hit the container at 20 knots and you’re dealing with a lot of momentum which in this case resulted in the pitch pole."

    Please, what is the origin of your capsize diagnostic ? Looking at the photo, there is no sign of collision on the under water hull or any appendage ? To my knowledge, sometimes ago there was no reliable diagnostic ?
     
  2. oldmulti
    Joined: May 2019
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    oldmulti Senior Member

    Patzefran. Source was from the attached web address TS5 Hallucine capsizes off Spain, hit UFO - Page 2 - Cruisers & Sailing Forums https://www.cruisersforum.com/forums/f158/ts5-hallucine-capsizes-off-spain-hit-ufo-242326-2.html by oscarkramer "I just received word that my brother-in-law, known French racer Regis Guillemot with 3 crewmembers, struck a partially submerged container and sank, with one crewmember lost. They were off La Coruna, Spain on the way to Martinique. The cat was a new (< 2years old) Marsaudon Composites 50' all-carbon cruising cat. They were likely sailing around 20 kts when they hit the container and pitch-poled. The details are sketchy still, but it sounds like one hull was severely compromised, while the other kept the boat from sinking immediately. The surviving crew made it into the life-raft and managed to send a signal. They were recovered 12 hours later by a cargo ship and taken to the Azores. This is the same boat, "Hallucine", that was first over the line in last year's ARC. Pics of the boat can be googled.

    This is a horrible tragedy for all involved, and it has me wondering. Firstly, fast cruising cat sailors (including my bro-in-law) argue that there is safety in speed: being able to out-run the weather and minimizing time exposed to the elements. That made sense to me until this event. Now a slow aluminum hull sounds a lot more attractive.

    Secondly, here is yet another story of a tragedy caused by the clear negligence of the cargo industry. Why aren't there regulations on tracking individual containers, providing mechanisms for fast sinking, emergency lighting, etc.?

    Is there a commercial product available to cruisers for looking ahead for submerged obstructions? My googling indicated one IR LIDAR device that seemed to be the ticket, but I don't find anyone selling it for the commercial market. Anyone have any experience with this?"

    The jpeg is of the boat when it was washed ashore as it hit the container in mid ocean. I agree there is a lack of clarity about the accident but I suspect it is under investigation due to the death of a crew member. The remaining crew were reputedly picked up in a raft by a passing ship. Any further details would be appreciated.
     
  3. oldmulti
    Joined: May 2019
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    oldmulti Senior Member

    The final comment on Hallucine during the ARC 2019 and its capability of doing 350 mile days. PBO report "The lead yachts in the Atlantic Rally for Cruisers are now arriving in St Lucia, with 50ft multihull, Hallucine, being the first to cross the line on Friday 06 December. Led by experienced ocean sailor Régis Guillemot, the four crew had a blast across the Atlantic, clocking up a record day of 385NM, an average speed of 15.2 knots, and sailing under main and asymmetric the whole way."

    The Seawind 1370 cat has “pre sold” 55 boats of this model with the first 1370 sailing in late 2020. The designers are François PERUS and Romain SCOLARI of YDC. The 1370 cruising catamaran is 45 x 25 foot with a weight of 24,250 lbs. The displacement is not specified but I would assume a maximum of 30,000 lbs. The mast is 64 foot high with an 861 square foot fat head mainsail and a 387 square foot self-tacking furling jib. There are optional Code 0 and spinnaker available with the “possible introduction” of a storm jib. Hmm, they claim this boat is a global cruiser. Seawind have said that the basic jib and main will satisfy most sailors. The hulls have a length to beam of 9.6 to 1 with fixed low aspect ratio keels with a draft of 4.25 foot. There is no daggerboard option. The rudders are spade. The underwing clearance is 2.75 foot.

    The sheets and halyards run under the deck in tunnels (with turning blocks) around the edge of the bridge deck cabin base to the edge of the cockpit so that the helmsperson can control the boat from the helm. This keeps the deck clear of any ropes whilst sailing according to the design team. There are hatches to clear any rope jams at turning blocks etc. The entire boat has been designed to centralise weights near the centre and be placed as low as possible. The aim is to minimise pitching and enhance stability.

    To give a feel for the Seawind 1370 it is 6,000 lbs (34%) lighter than the Lagoon 450 with only 150 square foot (12%) less sail area. Translation. The 1370 will be a higher performance cat compared to most other production cruising cats of the same size. There is a performance chart in the jpegs.

    There is a large door between the cockpit and main cabin allows open-plan living with the saloon, galley, cockpit and helm all on one level on the bridge deck which has 6.8 foot headroom. The hulls have 3 or 4 double cabins, 2 bathrooms and a single optional berth. This is a comfortable boat for its size. The 1370 carries 600 litres of water, 600 litres of fuel and holding tanks of 240 litres.

    The structure of the cat is a PVC foam e glass sandwich which is resin infused with vinylester resin in female moulds. There is carbon fibre reinforcement in selected areas of the hulls, strength bulkheads and forward prodder. There is a Kevlar layer in the hull layup forward underwater. The main forward collision bulkhead is horizontal to allow some light storage above it forward.

    The production plugs were robot cut from a foam block which then had a paste layer placed on top. The robot then did a final cut on the harder surface to provide a finished plug for the female moulds to be produced.

    This is an interesting design that is a half-way house between a French accommodation cat and a TS42 type very high performance cruising cat. The jpegs give some idea.
     

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    Last edited: Apr 4, 2021
  4. SolGato
    Joined: May 2019
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    SolGato Junior Member

    This a great thread and a fantastic resource Oldmulti!

    As you stated in your opening post, lots of ideas have been tried over time, some good, some not so good.

    This thread is a really great resource for anyone interested in Multihulls who has an interest in understanding the purpose of various design elements, whether they are looking to purchase or build their own.

    I’m a big fan of trailerable designs mainly due to our lack of marina infrastructure and my concern for hurricane season. I like being able to store my boat on my own property where a I can work on it at will, and fill it up and strap it down in the even of a potential hurricane.

    Prior to my purchase of the Seawing 24, I studied a number of designs that I found interesting that would have likely fit my needs.

    I did a quick search (I haven’t read through all 112 pages yet!) of a few of those designs, but didn’t find specific mention of them here and thought I might offer them up as possible topic suggestions. I have photos of some of them that I’ve collected from sales listings and internet searches of various forum and discussion posts.

    The designs are the Condor 30, Maine Cat MC22, and TomCat 20. The Condor like my Seawing is a demountable Tri design (I came very close to buying one), the Maine Cat is a really cool folding design, and the TomCat a demountable.
     
  5. oldmulti
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    oldmulti Senior Member

    SolGato. All information welcome. The Mainecat 22 was featured on page 38 of this thread but the TomCat 20 and Condor 30 tri have not been done. I will do a little research and feature them in the near future. Thanks for your input.
     
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  6. Dejay
    Joined: Mar 2018
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    Dejay Senior Newbie

    Wow what a brilliant design! And only 1450kg! I know they use carbon but how do you design multihulls to be that lightweight?

    According to their numbers at 7 knots they can go 35nm on a 8x100Ah battery (12V? So 9600kWh) which would mean they use about 1920kWh at 7 knots. You'd "only" need about 8 high performance glass solar panels (160kg) to reach that in sunny conditions.

    Too bad it only has 175cm headroom.

    Thanks for this thread oldmulti.
     
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  7. SolGato
    Joined: May 2019
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    SolGato Junior Member

    Whoops, I somehow missed the MaineCat feature. Had also forgotten it was a Newick design!
    I can’t imagine they’d be running a 12V motor system. You’d need to run higher voltage to efficiently produce the thrust necessary to safely maneuver a boat that big.

    I also wonder if these specs take into account the battery chemistry and the safe discharge factor in order to ensure life longevity of the bank.

    Although a lot of the newer LiFePo4 batteries can be discharged to zero, for reliability and longevity of life discharging down to 20% is a more realistic number to use when considering capacity and calculating traveling distance.

    I have future plans to scale up my Solar Electric Sailing Catamaran design and will be looking to build as big a boat as possible that can be quickly reduced to a legal trailing width like this design. Waiting for the right set of hulls to come along. There are a few project Stilletto hulls in the islands that change hands every so often that I’ve had my eye on.
     
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  8. patzefran
    Joined: Feb 2011
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    patzefran patzefran

    According to "https://voilesetvoiliers.ouest-fran...rescapes-491bc45c-237e-11eb-97e1-64af5fb563fa", According to Marc Guillemot, brother or Skipper Regis Guillemot, they were not doing 20 kt, nor pichpoled, but hitted something (UFO) while sailing conservatively and undercanvassed (two reefs) in 16 / 20kt wind and relatively flat sea. One hull flooded and they were pieces of carbon around, likely the capsize occured with vertical stem after flooding one hull .
     
  9. patzefran
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    patzefran patzefran

    I may add, from my own experience , it is not necessary to go fast to get damages sufficient to flood the hull when you hit something with a daggerboard. It happens to me on my Twiggy Trimaran in 1983 doing 7 kt to windward , fortunately, on a Trimaran with the mainhull fooded, you stay afloat thanks to the outriggers !
     
  10. bajansailor
    Joined: Oct 2007
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    bajansailor Marine Surveyor

    + 1 re Dejay's endorsement above - this is a very neat design indeed.

    Here is a link to the Builder's webpage -
    Innovate Freedom | Outcut 29.5 https://www.outcut.world/
     
  11. oldmulti
    Joined: May 2019
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    oldmulti Senior Member

    The Tomcat 6.2 (or 20) is a day sailing camp cruising catamaran. The Tomcat 6.2 was designed by Ted Strain and first produced in 2004. The Tomcat is 20.25 x 11.2 foot that can be disassembled to 8 foot wide for trailing. The minimum weight is 850 lbs but weighs 1100 lbs with a motor, rig and some fittings. The cat is also capable of 250 lbs water ballast in each hull. The rig is a Hobie with a 26.25 foot rotating aluminium mast with 210 square foot in the main and jib or 260 square foot in the main and genoa. The hull length to beam is 11.8 to 1. The hull draft is 200 mm. The central bridge deck mounted kickup centreboard when down draws 3.5 foot. The twin rudders are kickup and mounted on the rear of the bridge deck as is the outboard motor. About 40 TomCat 6.2 were produced.

    The concept of a Tomcat 6.2 is to cross the comfort of a powerboat with the sailing capability of a catamaran. The bridge deck can have powerboat type seating that folds down into 2 single bunks for overnight camping. The wind shield protects the crew from spray when sailing upwind. The windshield with a Bimini top and tent arrangement will provide a “enclosed cabin” space for overnight stops.

    The trialability of a Tomcat 6.2 depends on a special trailer. The custom TomCat 6.2 trailer includes all of the mechanisms required to assemble or disassemble the boat for highway travel. Twin hull racks roll out on extension bars and rotate the hulls upright, with the hull “bunks” now providing side to side positioning. Use the winch to lower the bridge deck into the hulls, fasten the bolts between the hull upper side notches to the bridge deck unit, and then you are ready to raise the rig and go sailing. The level bridge deck means that the motor, batteries and gas tank can remain in place during trailering. The assembly or disassembly task according to one owner takes 1 to 2 hours.

    Construction of the Tomcat 6.2 is mainly e-fiberglass PVC foam core sandwich composite for the hulls. The decks are reinforced with plywood in a glass sandwich. All glass is done by vacuum bag lamination in female moulds. Aluminium spars and stainless steel wire rigging. One weakness in the design commented on by several owners is the cable steering system from the steering wheel to the twin rudders. The cables tend to wear and break requiring replacement.

    There are limited tests of the Tomcat 6.2 sailing but the performance is considered good in light to moderate airs. One owner report said “I've sailed at 8-10 knots for sustained periods with occasional bursts above that. The bows do not plow in, and the helm is light.” A tester said “The bay is flat and the wind only 8 or 10 knots so the sailing is pleasant. With the large centre board, the cat sails upwind well. A large free-luff headsail could be set, doubling our sail area off the wind. "A prepared and capable crew could handle the boat easily in 20 knots without reefing," says Ted Strain. At that point, 30 gallons (250 lbs) of water ballast could be let into the windward hull to increase stability.” As with all Hobie rigged heavier cruising boats the limitation is likely to be the rig strength, not the boats stability, especially if water ballast is used. A 9.9 HP outboard will drive the cat at 8 knots.

    This is a practical camp cruiser for a short “cruise” for 2 or can carry 5 or 6 people for day sailing. A different but sensible approach. The jpegs give the idea. If you like the idea of the Tomcat 6.2, Richard Woods 22 foot Wizard catamaran design offers a home build foldable catamaran with more accommodation.
     

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  12. oldmulti
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    oldmulti Senior Member

    The Condor 30 trimaran was designed by Mick Price in 1988 for Condor Ltd. The Condor 30 is 31.4 x 24 foot with a claimed weight of 3,000 lbs. One Condor 30 was weighed for racing and came in at 5,152 lbs. Displacement unknown but assume 6,000 lbs. The 40 foot aluminium mast carries a 524 square foot rig in its basic fractional rig. The mainhull daggerboard draws a maximum of 5.75 foot. The mainhull rudder is a stern kickup.

    The 30 was meant to be an improved design on the Condor 40, and more flexible in use. It was made to be trailered, after “de-mounting” the amas and akas. Raising and lowering the mast uses the winch on the trailer, which is easy. Only four Condor 30’s were made. The accommodation has 4 berths, a toilet and galley area with full headroom. There is limited space but an owner had a Farrier 31 previously and found the Condor more comfortable.

    The designer Mick Price said “The design of the Condor 30 is a direct development from the Formula 40s and offshore race boats. The center of gravity, and thus the center of buoyancy, is slightly more aft, as is the rig, reducing the forces over the ama bows. This allows for the bows to be narrower, with the buoyancy distribution letting the boat take a bows-up attitude as it is being pressed harder. The water line beam is wider for its length, and shallower than the Condor 40 trimaran, which increases its water plane area, making it less sensitive to added weight. With the cockpit farther aft, the water line beam was carried farther aft to prevent squatting. In keeping with the recent design trends, a proportionally larger rudder was designed which gives the boat great handling and manoeuvrability with virtually no cavitation at high speeds. It also increases upwind performance by being able to load the rudder up with the mainsail.”

    The Condor 30 hull is constructed with Baltek’s AL 600 sealed balsa with uni-directional and biaxial glass. The decks and interior are all foam core and the entire boat is built exclusively with vinylester resin in female molds. The main hull is a one piece hand-laminated fiberglass with internal hull-deck flange using unidirectional, biaxial and triaxial E-glass with vinylester resin and an AL-600 epoxy sealed, end-grain balsa core with daggerboard trunk molded in hull. Floats are one piece hand-laminated fiberglass with internal hull-deck flange using unidirectional and biaxial E-glass with vinylester resin and an AL-600 epoxy sealed, end-grain balsa core. Structural bulkheads are hand-laminated with biaxial E-glass and vinylester resin with a PVC core. The bulkheads are fiberglassed on both sides to both hull and deck. Main hull and float decks are one piece hand-laminated fiberglass using biaxial E-glass, vinylester resin and cross linked foam core. The crossbeams are aluminium extrusions on the Condor 30.

    The interior is a one piece hand-laminated fiberglass using mat and core and then fiberglassed in main hull. The daggerboard is a 2 piece hand-laminated fiberglass using unidirectional and biaxial E-glass, vinylester resin and a vacuum-bagged AL-600 epoxy sealed, end-grain balsa core with spruce stringers. Rudder is a 2 piece hand-laminated fiberglass using unidirectional and biaxial E-glass, vinylester resin and a vacuum-bagged AL-600 epoxy sealed, end-grain balsa core with spruce stringers. Main hull and float hull deck joints. An internal flange bonded with 3M 5200 and thru-bolted through genoa tracks on the main hull and riveted with 6.4 mm SS rivets fore and aft of crossbeams.

    Performance is very good according to reports with excellent upwind capabilities and capable of hitting 20 knots under the right conditions. One owner said “we power-reached across the Bay to Santispac. It was the first time we sailed Quetzal in the high teens, and I was glad it was so dry, stable and well-behaved.”

    The original design was intended for coastal cruising and racing. An interesting design. The jpegs give the idea.
     

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  13. SolGato
    Joined: May 2019
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    SolGato Junior Member

    Interesting to read how overweight the 30 was. From what I understand, the same thing happened with the Condor 40 and that was partly the reason for developing the 30. I think the 40 was supposed to come in around 5800lbs, so hearing that a 30 was weighed at 5000lbs+ is surprising.

    I talked to one original long term owner about the procedure for mounting and demounting, and they mentioned they tried a number of methods including modifying the trailer to slide out and support the outer hulls, etc.. I wouldn’t be surprised if most owners just leave them assembled now knowing their true weight. In fact the only photo I could find of one disassembled on trailer is the same one you posted.

    If you want easy trailer-ability, I guess an F31 would certainly be a better choice although from what I’ve read and heard from owners, the Condor 30 is more comfortable and has a lot more storage.

    Here are a few more photos. Some of a Condor 30 and a couple of F31’s that sailed together to the Bahamas I believe out of Texas. It’s always neat when you see two different takes on design sitting next to each other dockside.
     

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    Last edited: Apr 6, 2021
  14. CocoonCruisers
    Joined: Dec 2015
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    CocoonCruisers Junior Member

    Here is the IR-cam + image recognition AI based one used on a few IMOCA's in this year's Vendee Globe
    Products – OSCAR NAVIGATION https://www.oscar-navigation.com/index.php/products/ I heard the ULTIM's use it too. It's pretty new still, and has been mentionned a few times with mitigated enthousiasm in the sailor and designer interviews; Sorry i don't remember the video links. Bottom line was they were all glad someone is taking on the problem, also seeing serious limits in larger waves (no sightline no detection). They thought such systems would soon be generalized in ocean racing and sounded pretty confident that they would mature quickly.
     
    Last edited: Apr 7, 2021

  15. Scuff
    Joined: Nov 2016
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    Scuff Senior Member

    Cocoon I checked the link you provided .. I tried to convert the pricing from euros to dollars but google says less than $100 for the brain and optics that can't be right.
     
    Last edited: Apr 7, 2021
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