Bolger 50' Wyoming into trimaran

Discussion in 'Boat Design' started by ASM, Nov 15, 2010.

  1. ASM
    Joined: Sep 2005
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    ASM Senior Member

    I have recently stumbled over a 50' Bolger design which I like because of it's simplicity, just enough oom available for good comfort and of course the knowledge it coul be cheap to build (hey I am a Dutchman ... !).

    Years ago I was here as well and initiated the faux tri with a lot of help of another boatdesigner on this forum , but this is still on the drawing board as I might see too much lions and bears in this design. Simplicity is where i want to start.

    However, I thought t might be doable to add outriggers on the 50' Wyoming to add some stability and have nice bathing platform or widened outside seating area. But, they have to be simpy to construct....

    Is this Idea completly stupid or has it got some potential ?
     

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  2. mydauphin
    Joined: Apr 2007
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    mydauphin Senior Member

    Structurally you are going to have a hard time holding the three hulls together. The forces involved are pretty great. Probably not worth the effort.
     
  3. ASM
    Joined: Sep 2005
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    ASM Senior Member

    Mydauphin,

    Thanks for the reply.... I believe you if you say structurally it will be a hard
    time, that is not my expertise..... But if one would use alu tubing, would that be ok ? I men, overdimension it so one has a safety margin ? The intended cruising area for Wyoming was inland rivers with occasional chop, so I do not plan to alter this.... would that men less strain on the structure as well ?

    I found this interesting link btw for A bolger style trimaran...

    http://hallman.org/bolger/554/Bolger554CampingTrimaran.html
     
  4. Steve W
    Joined: Jul 2004
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    Steve W Senior Member

    If i understand you right you are talking about a power trimaran, not a sailing trimaran, if so your overall beam will be much less and without the forces imposed by a sailing rig alloy tubes would work fine.
    Steve.
     
  5. ASM
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    ASM Senior Member

    Thanks Steve, yes indeed a (low powered) cruiser, not sailing. outriggers added will only be there to get some more stability and additional recreation space outside.
     
  6. luckystrike
    Joined: Feb 2010
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    luckystrike Power Kraut

    Hello,

    I don`t see any advantages in the Trimaran configuration. Why do you want to put a lot of wheight, windage, drag, hours and euros into a boat that is stable and complete as it is by design. Just to have a trimaran? It will not go faster with the same horsepower, it will be slower and more expensive in the habour.

    If you want simplicity it's no good Idea to add difficulties.

    If you just want to have a big bathing platform you can build one of the hullsides aft to be swung down to the water level. Like they do on the superyachts ... in a small scale of course, but possible on the Whyo I think.

    http://www.charterworld.com/news/wp-content/uploads/2010/06/The-Ruea-Yachts-60m-Superyacht-The-Side-Tender-Garage.jpg

    Sorry for that long link.

    Grreeetings from the North Sea Coast, Michel

    P.S. I have found some information about Whyo in the Bolger Book: "Boats with a Open Mind". Do you have it?
     
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  7. ASM
    Joined: Sep 2005
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    ASM Senior Member

    Lucky,

    I see your point and partly agree... though in my feeling 2.5 m width at 15 m length is tiny... and I would like to add stability because of my non-boating wife ;-). They also make nice step-aboard sections and do not plan to make it extremely wide.

    No I do not have theBolger Book unfortunately...
     
  8. messabout
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    messabout Senior Member

    Wyoming, as designed, is sufficiently stable. If the weight of the contents is kept low, the boat will survive fairly serious weather. Making it into a trimaran is not only a breach of ettiquette but also a breach of practicality. If you simply must have a multi, then you will be better served by starting with a multi design in the first place.
     
  9. larry larisky

    larry larisky Previous Member

    it looks good like that.
     
  10. luckystrike
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    luckystrike Power Kraut

    Sorry, I have no scanner. But if you want to understand this design and the way it works, it`s best you purchase the book anyway.

    The secret of this design are three features.

    The slim hull ... with a length to beam ration of 6 to 1 this hull is automatically a low resistence hull, even with its box shaped bulkheads. If you want a little more deck space you can redraw the bulkheads to give them a little flare. Perhaps up to 3m on deck leven. But you have to be very carefull in doing this because ......

    .... this is a light-displacement-boat with a very restricted load carrying capacity. If you overload this boat you will loose all its good qualities.
    So you can not make a houseboat out of this and have a good performing boat at the same time.

    The simple construction and the simple concept is the third feature of the design and supports the first two points without beeing expensive due to the relative low cost plywood and the small and fuel efficient engine needed.

    I'am not very familiar with motorboat design, but in general you can say that a slim boat like the Whyo has a not worse motion than a normal proportioned boat in a rough seaway.

    Bolger discribes in the book that the Whyo could be built using his stepped bulkheads used in the Hawkeye- and Sneakeasy (half scale Whyo) design. This would make a wider boat possible with more space. But someone must design this, because this will be a complete cange of plan.

    Anyway, it would be interesting to talk to somebody who owns a Whyo and could tell us if the boat performes like Bolger has promised.

    Grreeetings from the North Sea Coast, Michel
     
  11. sorenfdk
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    sorenfdk Yacht Designer

    The tubing is not your biggest problem.
    The biggest problem is that the structure of the boat is not designed to carry the loads from the tubes. In other words, you'll have to beef up the hull plating (at least locally) and probably add some bulkheads too. Maybe even add frames to resist the torsion in the hull induced by the outriggers.
    The calculation of these elements is not something you should do yourself unless you're a qualified naval architect.
    If you're planning to only cruise inland waters, then I guess the boat is stable enough as it is.
     
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  12. sabahcat
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    sabahcat Senior Member

    I imagine you are only talking about small outriggers down aft like this?

    [​IMG]

    But bigger?
     
  13. RHP
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    RHP Senior Member

    Three coffins bolted together?
     
  14. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    I don't know what the 50' Wyoming's roll moment is, but I would suspect it's not excessive. In fact, I would expect, based on several obvious factors, she's pretty much a rock solid platform, in the conditions she's intended to ply. Therefore I think the idea of a "Tri-oming" isn't valid or warranted and possibly an over reaction of an inexperienced skipper. This isn't intended as an insult, but a note about asking for design goals, that aren't necessary in the real world. This is fairly common among the novice designers of the world, to design for the worst case or attempt every eventuality or possibly to get a squeamish loved one to sail more often. Some things (like squeamish loved ones for example) are much better left to extortion and out and out bribery, mostly because the issues make for imposable design goals.
     

  15. messabout
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    messabout Senior Member

    Par; that last remark was a thoroughly practical philosophic truth.
     
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