Results 1 to 13 of 13

Thread: Plywood Dinghy Frame Material

  1. #1
    Join Date
    Mar 2018
    Location
    Delaware River, NJ, USA
    Posts
    6

    Default Plywood Dinghy Frame Material

    Hey All!

    I've finally got my hands on the plans for the Duster, and I've been studying for days. I'm planning on putting together a scale model first, just to get a feel for how all these bits go together, but there is one question that keeps rattling around my brain. On the plans, it specifies the kind of sheathing (3/8" Marine Plywood) and the material for the rudder and mast step (Mahogany), but it says nothing about the chines, clamps, frames, and deck beams.

    The Duster is designed to be built by amateurs, from readily-available lumber sources. Everything is 3/4" wide in some dimension. But what to use? White oak? Doug fir? Bubinga? Balsa? Okay, probably not the last two, but still. I know these things are designed to be light, but I don't think I'd trust anything, uh, pine-y for holding it all together.

    Thoughts?

  2. #2
    Join Date
    Oct 2013
    Location
    dfw
    Posts
    1,140

    Default Re: Plywood Dinghy Frame Material

    more information needed

    designer, size, style...

    sw
    "we are the people, our parents warned us about" (jb)

    steve

  3. #3
    Join Date
    Mar 2018
    Location
    Delaware River, NJ, USA
    Posts
    6

    Default Re: Plywood Dinghy Frame Material

    It's a 14 foot cat-rigged, centerboard pram called a Duster. Designed in 1933 in Riverton, New Jersey for the waters of the Delaware River just off...Riverton, New Jersey

    It's a local boat and part of my Yacht club's history, so I want to get one sailing out there regularly.

    They still sail 'em at the Lake Naomi Club out in the Poconos, but they fell out of favor down here around the time Lasers got big.

    Fun fact: The boat's beam is only 4'6", because it was designed and built on the third floor of 301 Main Street. The window up there only opened so wide, so they designed around the egress.

    Here's a photo of the Riverton fleet back in the heyday.
    Start_at_Riverton.jpg
    Attached Images Attached Images

  4. #4
    Join Date
    Oct 2008
    Location
    Walney, near Cumbria UK
    Posts
    41,005

    Default Re: Plywood Dinghy Frame Material

    Douglas fir, spruce, larch. Any straight grained knot free reasonably durable timber.
    How are the frames jointed at the deck, chines and keel?
    It really is quite difficult to build an ugly wooden boat.

    The power of the web: Anyone can post anything on the web
    The weakness of the web: Anyone can post anything on the web.

  5. #5
    Join Date
    Jan 2009
    Location
    se pa (Bristol PA)
    Posts
    3,061

    Default

    Cherry, or White Oak Haycock Sawmill Doylestown has millions of board feet of WO, but they mix it up with the red oak and it's hard to tell the difference on Lumber that's been sitting out in the sun and turned gray.

    Ash is great, but it rots in a heartbeat. if the boat is going to be in storage you'd be okay with that, if it's going to be in the water a lot and left in the water even longer don't want to use ash,

    You can get New Jersey Cedar also but it's just a little bit soft to use for scantling's.

    Doug fir, you can actually get in the big box stores but you have to look for it. Lowe's actually sells DG 4x4s 8 feet long.
    Delaware Valley, Delaware River,, a lot of the history of the boats has not really been preserved, I'm restoring a Delaware Ducker that's probably about a hundred years old,

    you would think Philadelphia's Independence Seaport Museum would have a lot of the history research, but I would say it's spotty at best.

    Good luck on your build, this your first?
    Denise, Bristol PA, Oday30, Anchor Yacht Club, On tidal Delaware River. my current project; http://forum.woodenboat.com/showthre...0-Ducker-Resto

  6. #6
    Join Date
    Mar 2018
    Location
    Delaware River, NJ, USA
    Posts
    6

    Default Re: Plywood Dinghy Frame Material

    Quote Originally Posted by Peerie Maa View Post
    How are the frames jointed at the deck, chines and keel?
    The plans call for various lengths of #10 screws. The boat has an internal keelson, all plywood bottom, and the frames only run from the clamp to the chine. The deck beams are set into the frames a bit to distribute the load.

    Quote Originally Posted by DeniseO30 View Post
    Good luck on your build, this your first?
    It is! I just moved to a new place with garage space, and much closer to the club. Now is the time!

    I actually remember talking to you over on sailnet way back when. We chatted about sailing O'Days on the Delaware

  7. #7
    Join Date
    Nov 2011
    Posts
    5,435

    Default Re: Plywood Dinghy Frame Material

    Go to the lumber yard and look thru the Doug Fir 2x10s and 2x12s. You should be able to find enough of them that have nice clear tight grained wood on one or both sides of the heart center. Don't use the sapwood, it rots easily.

    Once you've cut out the framing bits and pieces you can probably use what's left to build the ladder frame and the saw horses it sit's on.

  8. #8
    Join Date
    Dec 2003
    Location
    Sound Beach, NY
    Posts
    3,575

    Default Re: Plywood Dinghy Frame Material

    If you have access to any of the old ones you might be able to judge by examining them. I don't think that taking a shaving would be polite, but knocking on it, pressing with a fingernail, looking closely at the grain all would be clues.

  9. #9
    Join Date
    Mar 2018
    Location
    Delaware River, NJ, USA
    Posts
    6

    Default Re: Plywood Dinghy Frame Material

    Quote Originally Posted by johngsandusky View Post
    If you have access to any of the old ones you might be able to judge by examining them. I don't think that taking a shaving would be polite, but knocking on it, pressing with a fingernail, looking closely at the grain all would be clues.
    The old wood ones are few and far between, but I may have a contact for getting my hands on one when it's time to get out there and buy some wood.

  10. #10
    Join Date
    Jan 2009
    Location
    se pa (Bristol PA)
    Posts
    3,061

    Default

    It may be nice to look at an original and maybe dive deep into it and find out exactly what Woods were used, but it's hardly worth the trouble making something historically accurate for something that is not historically significant to anybody but the people who think it is!

    Is it is worth the effort? Probably not just build it be happy, it's not likely anyone but you will ever care how accurate it is to the original build.
    Denise, Bristol PA, Oday30, Anchor Yacht Club, On tidal Delaware River. my current project; http://forum.woodenboat.com/showthre...0-Ducker-Resto

  11. #11
    Join Date
    Jun 2010
    Location
    Between Bourgeoisie and Proletariat - Australia
    Posts
    2,326

    Default Re: Plywood Dinghy Frame Material

    Concur, DF.

    You'll be epoxying inside and out?
    Have you considered CPES on every component before installation - guarantees longevity for a relatively small expense. Puts rot almost completely out of the picture (save damage).
    Mahogany for rudder etc... Nice if you can. I'd be doing DF for the step and 12mm (1/2") ply (sheathed with some glass if you have it) for rudder and dagger board.
    "People should be able to access these benefits [Social Welfare] as a matter of right, with no more loss of their own standards of self-respect than would be involved in collecting from an insurance company the proceeds of an endowment policy on which they have been paying premiums for years."
    Robert Menzies - Liberal Party (Conservative) Prime Minister of Australia.

  12. #12
    Join Date
    Dec 2003
    Location
    Sound Beach, NY
    Posts
    3,575

    Default Re: Plywood Dinghy Frame Material


    I didn't suggest looking at an old one for historical accuracy, but rather to see what has already worked for decades.

  13. #13
    Join Date
    Nov 2011
    Posts
    5,435

    Default Re: Plywood Dinghy Frame Material

    If you're concerned that DF won't hold screws as well as oak or mahogany, which is probably not a problem any way, you can bed all of the joints in Sika or epoxy. Besides backing up the screws and making for a stronger less leak prone hull that will exclude moisture from the joints thereby forestalling rot. Rot starts in the joints.

    If you use epoxy you can even remove whatever bright steel screws you used to hold the joint closed while the epoxy cures and fill the holes with dowels in thickened epoxy. Then you won't ever have to deal with rust. Removing rusted screws can be very tedious.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •