Bolger's Prince William Sound Yawl

Discussion in 'Boat Design' started by Tom Painter, Jun 11, 2020.

  1. Tom Painter
    Joined: Jun 2020
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    Location: Maine

    Tom Painter New Member

    Hi gang,

    I hope I have posted this in the right area...

    I'm thinking about building Bolger's PWSY from Different Boats. The design brief was for a light weight beach cruiser that could be car-topped. The original construction detail (IIRC) was two courses of 1/8" cedar double diagonal sheer to sheer. No inside stringers(!) which seems very, very light, maybe too light. I can't remember if he called for a sheathing as I don't have the book in front of me (on vacation), just some scans of the lines, construction plan & sail plan.

    Anyway, I was thinking about building her foam core fiberglass because she's a bear of a shape to make in any wood method, but I'm much more knowledgeable about wood construction than glass composites...

    What would be some appropriate scantlings?

    3/8 divinicell core (H80?)

    What should the skins be? Would 2 layers of 10oz FG cloth inside and out be adequate? Keep in mind she's a light weight 16' (680# disp) car top beach cruiser.


    [​IMG]PWSY model by T P, on Flickr

    [​IMG]PWSY sail plan by T P, on Flickr
  2. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    If you didn't sheath the original; it'd be short lived.

    I'd say your lamination plan is a bit light on the glass. All I can offer. Definitely going to need some stitch fabrics.

    you might need to give the details like length on water, beam, etc., even then developing the boat from ply unknowns to foam is really not just dartboard stuff

    I am only smart enough to tell you you are too light. You also need to use some HD foams, etc.
  3. Tom Painter
    Joined: Jun 2020
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    Location: Maine

    Tom Painter New Member

    Here's the original construction plan.

    She's 16.25' LOA, 4.5' Beam

    [​IMG]PWSY construction by T P, on Flickr
  4. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    I don't usually like Bolger's designs, but that is a beauty. Get Dave Gerr's book for scantlings and reinforcements. It's a cookbook system where you simply enter the boat's dimensions and the formulas give you everything you need.
  5. Tom Painter
    Joined: Jun 2020
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    Location: Maine

    Tom Painter New Member

    Yeah, I've got it sitting at home on my bookshelf...
  6. JSL
    Joined: Nov 2012
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    Location: Delta BC

    JSL Senior Member

    "car-topped?" make sure you have a large car and the proper setup to load the boat.
  7. Squidly-Diddly
    Joined: Sep 2007
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    Location: SF bay

    Squidly-Diddly Senior Member

    See my latest post.
  8. Wayne poulsen
    Joined: Apr 2018
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    Location: Australia

    Wayne poulsen New Member

    It was a long time ago...but its a timeless design.
    Two years of covid later...

    A friend of a friend built this boat, unfortunately i never saw it.
    They were reportedly happy with it.
    I always admired the design, make a fine dayboat/dinghy cruiser.
    When it was first finished they were not happy with the flex in the 1/4" bottom.
    Bolger was contacted and was not phased or surprised, he endorsed more stiffening.
    I dont know how.
    That foam/glass scantling would be best tested.Bear in mind the 1/4" ply is only inadequate on the large flat bottom. Only the bottom needs some extra material.
    I would love to hear that the boat was built.
    Fremantle Australia

  9. wet feet
    Joined: Nov 2004
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    Location: East Anglia,England

    wet feet Senior Member

    It wouldn't be too hard to add stiffening to the bottom of the wooden version.A pair of bilge keels,say 3/4" deep and the same width,laminated in place and extending a few inches beyond the bulkheads and tapered away at the ends would help a lot.Additionally,it wouldn't be a huge project to laminate 3" wide strips of 1/8" veneer internally in the least supported areas.A close look at the cold moulded hulls of older International 14's would probably give some inspiration.I don't suppose it would add more than 5lbs which you would notice if you had to car top such a big hull.
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