Extending a 31' Prout front +6' ,rear+4'

Discussion in 'Boat Design' started by jon haig, Jun 26, 2019.

  1. jon haig
    Joined: Jun 2019
    Posts: 20
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    Location: pompano beach,fl

    jon haig Junior Member

    Some opinions on speed if i extend a 31' prout by 6' bow,very sharp
    reverse entry wave piercing bow. and added 4' to rear for steps/stairs. i intend to do in solid fiberglass.
     
  2. Deering
    Joined: Feb 2005
    Posts: 477
    Likes: 22, Points: 18, Legacy Rep: 44
    Location: Juneau, Alaska

    Deering Senior Member

    I just finished such a project and it appears to be successfully meeting my original objectives. I did not appreciate the complexity of it. You’re talking about modifying the two most complex ends of the hull. There’s a reason why boats get lengthened by cutting them in half in the middle where the runs are parallel. The bow is complex but doable. If you get into having to modify the rudder...you just immensely increased the complexity.

    Plan on doubling your budget and tripling your time estimate. I wouldn’t do it again knowing what I know now.

    How would you do it in solid fiberglass? Do you have molds?
     
  3. jon haig
    Joined: Jun 2019
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    Location: pompano beach,fl

    jon haig Junior Member

    do you have a picture. the 4' at rear for sewage and water on other side. will be beyond the rudder.rudder stays as it is. The front will be sculpted to shape using styrofoam, then glassed to thickness and overlapped onto hull maybe 12" inside also glassed to hull.original bow remains inside intact.access port to view inside of front addition will be from top round hatch. for lightweight stuff.
     
  4. jon haig
    Joined: Jun 2019
    Posts: 20
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    Location: pompano beach,fl

    jon haig Junior Member

    styrofoam 2" panel for shaping. and glassing on top, BUT not directly to it, it will melt.
     
  5. Alik
    Joined: Jul 2003
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    Location: Thailand

    Alik Senior Member

    This would be significant increase in weight.
    Most of catamarans after such extension would experience structural issues as the structure is not designed for such increased weight.
     
  6. jon haig
    Joined: Jun 2019
    Posts: 20
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    Location: pompano beach,fl

    jon haig Junior Member

    Not to mention the increased buoyancy?will see when actually done and used in 10' seas.
     

  7. Deering
    Joined: Feb 2005
    Posts: 477
    Likes: 22, Points: 18, Legacy Rep: 44
    Location: Juneau, Alaska

    Deering Senior Member

    Here’s the bow extensions. They are aluminum 6FF79882-92E9-42FD-9F82-4CFB1E93E0C2.jpeg
     
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