New folding mechanism for old Texas Trimaran

Discussion in 'Multihulls' started by Texas-Tri, Sep 27, 2007.

  1. Texas-Tri
    Joined: Sep 2007
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    Texas-Tri Junior Member

    I am a newbie poster but a long time lurker on this forum (I’m not sure if lurker is the right word, but I’ve been reading all your posts for a long time). I have just taken the plunge and purchased a beater 24 foot trailerable trimaran. It needs lots of work but it has good solid fiberglass amas and main hull. I plan to re-design the folding mechanism, and possibly the cabin if I get real enthusiastic. I’m sure that I will have lots and lots of questions for ya’ll, but for starters, I’m trying to find out something about the boat I bought. It is a “Texas Trimaran” or “Tex-Tri” I believe it is late sixties or early seventies vintage. A Google search comes up with very little on these. Has anyone ever heard of these? Any comments on the basic hull design? Is it worth the energy to bring this thing back to life? Also, any ideas on home built folding mechanisms? I’d like to come up with something relatively simple that can be folded/unfolded on the water. The Corsair/Farrier design is nice, but may be too difficult to make on my own (I am trying to do this on the cheap).
     
  2. Chris Ostlind

    Chris Ostlind Previous Member

    Get that digital camera out of the bag

    How about some photos of the boat as she sits right now... inside and out from several angles? Really can't make any comments, except in a very general sense, without knowing what the issues might be.
     
  3. Texas-Tri
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    Texas-Tri Junior Member

    Pictures of Texas-Tri

    [​IMG]

    I've inserted a Snapfish link to a photo album of the boat. I hope the link works ok. It’s a 24’ Texas Trimaran. These were built in or near Corpus Cristi Texas in the late 60’s and early 70’s. This particular boat hasn’t seen the water for ten years and has rotted a back yard since then. The hulls and amas are solid fiberglass. The deck and cabin are plywood/fiberglass. The folding system seems to utilize wood 4x4 technology :confused: , and I am amazed by the flimsy hinge and locking mechanism. I can’t believe that this system held up in any kind of weather. All of the fiberglass seems pretty solid but the wood deck on the amas, and some of the wood in and around the hinges is rotted. I want to redesign the folding mechanism so that the amas can be folded/unfolded while on the water. Any comments would be very much appreciated.
     
  4. Texas-Tri
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    Texas-Tri Junior Member

  5. Lt. Holden
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    Lt. Holden Senior Member

    Texas Tri- Ama Hinges

    Interesting looking boat! I agree the hinge setup looks shaky at best. Have you considered "Ratcheting Ladder Hinges" (used on folding/multi-configuration ladders)? They are very compact, strong, and can be set to various angles(if you wanted to adjust the weight distribution between the main hull and the amas. You might even consider buying a ladder unit and cutting it into sections so you could use a ladder section with its attached hinge as its own frame.
     
  6. Texas-Tri
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    Texas-Tri Junior Member

    I hadn't ever considered using ladder hinges. It's actually an interesting idea though. It would definately fall into my "doing it on the cheap" philosophy. Do you know if anyone has ever tried that before? Does anybody know what kind of forces should be anticipated for the beams on a 24 foot trimaran?
     
  7. Texas-Tri
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    Texas-Tri Junior Member

    Moving amas out and forward? good or bad?

    Thank you to all of you who have helped me id my boat. I believe my Texas Trimaran is a fiberglass version of the Piver Nugget 24. I will be reworking the cabin, the beams, and the folding mechanism. I have two questions that I would love to get some feedback on:

    Is there any advantage or disadvantage to moving the amas out from the current beam of 14.2 inches to an increased beam of about 16 feet? My thinking is that this would make the boat more stable and increase deck area slightly. I think I could do this and actually decrease the weight from what it is now. (The existing deck is very over built). What are the advantages and disadvantages of doing this?

    It would help make the accommodations more comfortable and the folding mechanism easier if I moved the amas forward so that the fronts are exactly even with the bow of the main hull. It seems like this is the trend in more modern designs. are there advantages or disadvantages to doing this with an old Piver design?

    I have posted sketches of the proposed changes on the following link: http://www.flickr.com/photos/14273927@N03/
     

    Attached Files:

  8. GTO
    Joined: Jul 2007
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    GTO Senior Member

    I just noticed your post and since no one else has replied, I'll toss out my thoughts on the matter.

    First, I would not increase the beam. The hinging posts acting as levers, any increase in length is going to greatly increase the force on the hinges. If you did increase the beam, I certainly would not reduce the structural strength of the supporting structure, unless you did some number crunching.

    Second, if you do move the hinging point forward, make sure the hull structure at the new location is strong enough for the new forces. I'm thinking of hull twist as the biggest worry.

    Next, I would not move the amas forward (without more number crunching) as this would change the weight/balance of the hull.

    I would rebuild the deck as you have shown, moving the hinge post forward on the hull/deck structure and on the ama. Then for peace of mind, I would ensure that the hull framing around the new hinge point (for both main hull and ama) were at least as strong as the original support structure.

    I just received plans for a 16' open daysailor trimaran (an old Popular Mechanics article) and I am not happy with the large truss structure it details for the ama supports. So like you, I'm currently trying to figure out how to rework the support structure before I actually start building. Good luck and post pics of your final solution please.
     
  9. Texas-Tri
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    Texas-Tri Junior Member

    I Won't move amas forward

    Thanks for the input. I have had the opportunity to talk with a couple of people who have sailed Piver Nuggets. Based on their feedback I have decided not to adjust the position of the amas. The Nugget tends to drop at the stern as the speed increases so moving the amas forward would certainly be a mistake. When I first had the idea of moving the amas, I didn’t realize that my boat was based on the Piver Nugget design, which is a well-proven design. The Nugget owners also seemed to think that the beam was appropriate so I will probably not change the beam although I’m not 100% sure yet.

    My design priorities for this boat are:

    1. Easy to launch
    2. A big enough cabin for three people to overnight in
    3. The best sailing performance possible

    My design challenges now will be to make large enough accommodations for three while keeping the weight low enough to have good sailing performance. I will probably have to make a small cabin that is expandable somehow. Any comments would be appreciated.
     
  10. GTO
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    GTO Senior Member

    It sounds like we have a common interest. I hope to find or build a trailerable boat suitable for a few weeks of sailing in the Bahamas, launching from Florida, with a couple on-board.

    I had thought a tri would be just the thing, but now I'm not so sure. It's the light weight and narrow hulls that give the tri its performance, but neither characteristic makes for a comfortable RV cruiser. Plus the trailerable restriction causes more trouble.
    However, I'm looking at something around 28 to 30 feet, so I might find something yet. Used Telstar 28 maybe.

    Three people in your 24' tri is going to be tight, no matter what you do. Looking at the interior photo, it looks like you could fit a folding bed frame that would allow at least 2 people to rest in some comfort across the 2 wing bunks. The third could then have a single bunk underneath. Somewhat tight, but I think a camping atmosphere is going to be inevitable.

    Following the camping angle, move the cabin forward as you propose, but then shorten it to just a galley, port-a-potty, and storage area only. Add a sponson bulge on either side under the wing deck for more storage. Then, have a water-resistant cover made (or modify a tent) that would allow you to convert the expanded cockpit into a big tent after a days sail. With the extra rear deck area you propose, plus the area freed from the cabin, 3 people might have room to spread out with some comfort, while leaving the cabin area free for cooking, etc...
     
  11. RHP
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    RHP Senior Member

    Tex,

    Looking at your boat the Telstar 26 immediately strang to mind. Take a look at the folloiwing UK link and see what you can come up with ref the ama. To get the best advice, call Tony Smith himself at Telstar who know make the new model 28 and ask his advice?

    http://mlm.invictanet.co.uk/telstar/index.htm or for the USA www.telstartri.org

    On the other hand and possibly the simplest solution, before you spend any more hard-earned, why not simply buy a secondhand Telstar 26 for under $10,000 in the UK/US? I´ve been aboard a few and they are quick, safe and surprisingly spacious below - there used to be one moored at Meols, lads.... :))

    Richard
     
  12. catsketcher
    Joined: Mar 2006
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    catsketcher Senior Member

    Beams again

    Hello all,

    I tried putting my two cents in before but it didn't load. If you are keen to ressurect the old tri I would use a waterstay to make the whole thing much stronger. I had a Nugget for about 7 years - good boat for inshore waters and a little protected coastal stuff. Then again one did go to Hawaii.

    Look at Twiggys, Vals and the Ama 35 and Dragonfly for a good idea on waterstays. Chris White has a bit on it in his book on cruising multihulls. The waterstay converts your cantilever beam to a compression beam which is much stronger.

    Use epoxy glue to make very close fitting end caps when your beams are up in their position. Coat one beam end with wax and then add filler to the other end and lift up - the excess eopxy will squeeze out and leave you with a lovely fitting join.

    I would use composite chainplates for the waterstay ends. Use about 8 layers of 600gm uni 100mm wide and lapped onto a bulkhead or string point about 300mm. No leaks and nice and strong.

    cheers

    Phil Thompson
     
  13. Sailor Sam
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    Sailor Sam Junior Member

    Please can you tell me about Ladder Hinges

    Thanks
     
  14. Texas-Tri
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    Texas-Tri Junior Member

    Waterstays?

    Thanks for the advice about the waterstays on your Piver Phil. I'm starting to think that rebuilding the existing folding mechanism (with the addition of waterstays) might be the best solution although I still have a hard time trusting that this simple hinge is a strong enough joint to take all the load.

    Phil, would it be possible to get some more details about the composite chainplates and how they attach to the hull or bulkhead? I am only know about stainless chainplates. I assume that these would attach through the main hull to the bulkhead under each of the cross beam supports at some point just above the waterline (at maximum heel). On my boat, this bulkhead is a square and hollow fiberglass tube about 4" square that runs the whole cross section of the fiberglass hull. I'm not sure how to best attach waterstay chainplates to this. I assume that they could potentially have as much or even more load than the mast stays, and the last thing I would want is these pulling out and creating a hole at the waterline!
     

  15. catsketcher
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    catsketcher Senior Member

    Chainplate construction

    Can you post some more pictures of the bulkhead re inforcing?

    cheers

    Phil Thompson
     
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