Design in progress: 26 ft center cockpit Catboat with aft pilothouse, Comments needed!

Discussion in 'Boat Design' started by valery gaulin, Aug 7, 2018.

  1. valery gaulin
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    valery gaulin Senior Member

    This design is the study of a Center cockpit catboat with an aft pilothouse, intended for coastal cruising (weekend and week trip) with a family of 5.

    Lenght: 26 foot
    Beam: 13 foot
    Draft: 2 ft (board up), 6.5 ft (board down)
    Displacement: 11 500 lb
    Sail area: 500 to 600 sq ft
    Engine: 25 hp high trust outboard
    Dummy: 6 ft. 3 in. tall

    In the pilothouse, there will be a small galley with a small dinning area and a interior helm station. Forward each side of the cockpit there will be on each side a full size double berth. Forward in the bow area there will be the master bed with a small toilet on port side and a shower on starboard side.

    Sleeping capacity: 8 total: 2 on the dinning table in the pilot house, 2 port side berth, 2 starboard side berth, 2 master bed in the bow. Optimal number would be 5 person ( 2 adult and 3 kids).

    The cockpit (6.5 ft long) is self draining in the centerboard slot.

    I am at the early stage of drawing but any comments is welcome to improve my design.
     

    Attached Files:

  2. Peter Vella
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    Peter Vella Junior Member

    What material is it to be built from?
     
  3. gonzo
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    gonzo Senior Member

    You should build it from whatever material you are more proficient with. Secondly, whatever is available locally. By the way, the drawing you show is a yawl, not a cat. Another important point to consider, is that the material you will build with determines, to a great extent, the best shape for the boat.
     
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  4. valery gaulin
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    valery gaulin Senior Member

    If I ever built the method will be cold molded construction. Douglas fir plywood covered with Xynol cloth set in epoxy. Maybe for the bow and the bottom a Kevlar layer. All ballast will be under the cockpit sole on each side of the centerboard. Probably to keep cost down cast iron brick would be used. Also because it is a shallow draft sailboat it is important in an emergency if ever running aground to be able to empty the ballast brick to float higher. The reason is that when someone venture in the shallow area there is not many other boat that can come help you if you get stcuk in a remote area!

    @gonzo : Actually because the mast is in front of the pivot of the tiller it would be consider a ketch! More precisely a cat- ketch... But in the early design options I considered a pure catboat, (one large sail). It seams that the mizzen will be more user friendly. Especially when motoring, at ancor and while raising the sail, it will keep the bow facing into the wind.
     
  5. Peter Vella
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    Peter Vella Junior Member

    Unless you already have iron bricks of the right weight and shape to fit in the bilges it is not really a cost saving over lead bricks. The lead itself is more expensive but you can cast the bricks yourself whereas you would have to pay a foundry to cast your iron bricks. The cheapest option would be scrap iron in concrete, but that would take up more space in the bilge.
     
  6. fallguy
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    fallguy Senior Member

    Have you done the hydrostatics? I am no sailboat guy, but it looks fat and slow like an old rowboat I own.

    Please don't be offended. I really don't have anything other than the hull speed calc in my peabrain.

    And the displacement and beam sort of makes it seem like it could be slow for you. Slower than hull speed max? I don't know.
     
  7. JamesG123
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    JamesG123 Senior Member

    See all the foiler and scow bow threads.
     
  8. valery gaulin
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    valery gaulin Senior Member

    @Peter Vella : I am sure there is a company that produce cast iron brick! Other wise a fat steel rod rectangular shaped cut into brick would work. Very similar density. Otherwise I know for sure, because I cheched, it is possible to buy lead brick, already made.

    @fallguy : No I have not run any hydrostatic. The dimension and ratio are in the catboat tradition, beam = half LOA, but with a more modern and unorthodox twist to it. The beam gives excellent initial stability, I could probably double the sail plan for light wind area! But it is not the purpose of my design. It should achieve hull speed with around 20 hp.

    This hull shape is not intended for offshore cruising. It is intended for coastal crusing and short passage in the Caribbean.
     
  9. gonzo
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    gonzo Senior Member

    There are a few companies that sell used lead shot quite cheap. You simply need to put it in bags, and they will take the shape of the bilge.
     
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  10. Peter Vella
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    Peter Vella Junior Member

    Is there a reason for the tugboat style bow? It will be harder to build than a pointy bow and seems like it could be a detriment when sailing into a head sea.
     
  11. valery gaulin
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    valery gaulin Senior Member

    @Peter Vella : The rounded bow for this type of design should give more advantages than a pointy bow.
     
  12. Peter Vella
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    Peter Vella Junior Member

    In that case you have to consider how you are going to build that shape and if the extra effort is worth it. I think the current hull shape will preclude anything other than cold molded wood construction or GRP. If you had a conventional stem then you could consider strip planking, or glued lapstrake if you want to use plywood.
     
  13. BlueBell
    Joined: May 2017
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    BlueBell Ahhhhh...

    Hmmm, kinda like a non-piercing bow.
    I don't care for it but don't let me slow you down.
    Build it and post lots of pictures!!
     

  14. JSL
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    JSL Senior Member

    Lenght: 26 foot
    Beam: 13 foot
    Displacement: 11 500 lb <---- *

    I agree with some other 'replies': this does not look like much of a performer and the layout description is like squeezing a quart into a pint. (or a liter into a milliliter)
    re: ballast. Iron is okay but can affect your magnetic compass if you have one.
    *That's a heavy 26' boat
     
    Last edited: Aug 10, 2018 at 11:06 AM
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