Inverted Bow Design

Discussion in 'Boat Design' started by Nico Crispi, Aug 6, 2017.

  1. Nico Crispi
    Joined: Jun 2017
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    Location: NE FL & SOCAL

    Nico Crispi Junior Member

    The following is an article on various bow designs on multihulls:

    A Look at Wave-piercing Bows on Multihulls - Sail Magazine http://www.sailmagazine.com/multihulls/a-look-at-wave-piercing-bows-on-multihulls/

    The inverted bow design and its variants are now seen frequently on all kinds of boats and sizes, from small sailboats to large powerboats.
    I will be soon starting construction on a 40ft long distance cruising trimaran in West epoxy system and I'm giving these designs a lot of thought.
    The boat's designer is conservative and stops short of embracing the trend but is open to consider my preferences and design accordingly.

    What are your thoughts on the subject?
    Sorry if this has been discussed here before but a search didn't reveal any such thread.
     
  2. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    The way an inverted bow hull strikes the waves is completely different from a traditional forward bow.
    You should not start a design by the shape of the bow. You define SOR perfectly and, as a consequence of it, the need for an inverted bow will arise. The designer can decide the bow that best suits the characteristics of your boat. Done that, if you want, change the bow as you like. The designer, I am sure, will be able to make the relevant changes in the hull and will show you the advantages and disadvantages of your decision.
     
  3. Nico Crispi
    Joined: Jun 2017
    Posts: 47
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    Location: NE FL & SOCAL

    Nico Crispi Junior Member

    Thanks TANSL. It appears to be a developing science much as the pitchpoling of the NZ AC45 showed us.
    I am interested in the Farrier 39 shape of bows as I'm aiming for a lesser pitching motion and thus a more relaxing ride for the occupant and the rig.

    Maybe somebody will chime in with direct experiences or a link to such.
     
  4. TANSL
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    TANSL Senior Member

    The great old warships already had inverted bows. It is not, therefore, an invention or a recent fashion.
    In my opinion, for speed catamarans is very suitable because it greatly reduces the bow waves and the interaction between hulls as well as the vertical movements of the hulls.
     
  5. Nico Crispi
    Joined: Jun 2017
    Posts: 47
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    Location: NE FL & SOCAL

    Nico Crispi Junior Member

    Right you are.

    Plus ça change, plus c'est la même chose.
     

  6. TANSL
    Joined: Sep 2011
    Posts: 6,481
    Likes: 386, Points: 93, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

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