Trimaran scow bow

Discussion in 'Multihulls' started by Sylvain Savoie, Apr 3, 2023.

  1. Sylvain Savoie
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    Sylvain Savoie Junior Member

    Any opinions on a scow bow for a trimaran or ever heard someone design one?
  2. bajansailor
    Joined: Oct 2007
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    bajansailor Marine Surveyor

    For the main hull, or for all three hulls?

    What are your thoughts re a scow bow for a trimaran?
    Are you looking to design and build one? If so, what size?
    Do you have any preliminary sketches that you could post if so?
  3. Sylvain Savoie
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    Sylvain Savoie Junior Member

    Thinking of the main hull only amas would be better i think having a sharp edge for wave cutting
  4. Sylvain Savoie
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    Sylvain Savoie Junior Member

    Right now just informing myself in new design see if anyone has som design out there
  5. oldmulti
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    oldmulti Senior Member

    Sylvain. For those who wish to try something different go to those who thought differently. Phil Bolger 23 foot scow based tri. I don't know if plans are still available but it may give some idea.

    Attached Files:

  6. seandepagnier
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    seandepagnier Senior Member

    Is the idea to surf even better as well as have an even lower draft than a typical trimaran?
  7. John Perry
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    John Perry Senior Member

    My thought is that scow bows are proving to work well on some monohulls at least in part because they allieviate some of the problems of hulls that have to sail at a large angle of heel. Monohulls have evolved to become wider (with some exceptions of course) driven by the need for form stability to maximise sail area to weight ratio and also driven by a desire for wide sterns to allow a wide cockpit and aft cabins. But increasing the width of a monohull that has a conventional pointy bow results in a close to triangular boat as viewed by a seagul. When a wide triangular boat heels over it is sailing on one of the long edges of the triangle so the stern lifts up and the underwater part is wanting to sail in a different direction to that which the keel is pointing. The keel wins, going the way it wants to go, so the rest of the underwater part is dragged slightly to leeward which is probably not so good. A scow mitigates these problems since when heeled over it sails more on one edge of a rectangle rather than on one edge of a triangle and if it has a flat bottom then heeling lifts much of that bottom out of the water reducing wetted surface. However, these advantages only apply to boats that sail at a considerable angle of heel, they are lost on multihulls that normally sail fairly upright.

    Multihulls can have a problem with pitch poling because their inherently high lateral stability encourages a big tall rig but the pitch stability of their typically narrow hulls is less than that of a comparable monohull and in an extreem situation the whole weight of the boat may go onto a single narrow lee bow resulting in the lee bow submerging then a capsize over the lee bow. A low freeboard scow bow, such as on the main hull of the Bolger design above, might perhaps tend to bury even more than a conventional multihull bow once the foredeck goes under? I note that Bolger only drew this style of bow on the main hull, the floats which are critical in the lee bow burying situation have a more typical multihull shape. Having said that, the floats on this design appear to be short and very low volume and one would think they would easily be submerged if the boat is sailed hard.
    bajansailor likes this.
  8. redreuben
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    redreuben redreuben

    Scow bows have enjoyed a renaissance with 6.5 mono racing as far as I can ascertain more particularly downwind racing and I think that is their niche.

  9. waterbear
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    waterbear Senior Member

    Neat! I wonder how bolger felt about the buoyancy of those amas? I know that was an issue with the Tremolino, and also the Strike 18 where they are not advised.
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