Wood on Tin

Discussion in 'Boat Design' started by Speedqueen, Feb 1, 2017.

  1. Speedqueen
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    Speedqueen Junior Member

    I am doing a restoration on a 1958 Starcraft Speed Queen, she is a little 14' aluminum runabout. During the tear down I removed the bow cover and discovered it was an aluminum skin over plywood. When I took the skin off a light went off I have wanted to do a wood on tin boat and this boat is the perfect candidate. I hope this is not upsetting to the purists, I know the guys that restore old starcrafts don't take kindly to restorations that do not keep the stock bow so I hope I don't offend the wood boat guys as well.

    The boat has white oak gunnels two boards on each side of the aluminum they are 1/2" thick by 1-7/8" total thickness 1", I plan attaching the bow cover over the gunnels and having white oak trim on top of the plywood.

    I do want the bow to have a little curve to it so it will have to be a little flexible. My question is what thickness should the plywood be? I will have a seam in the center of the bow due to the dimensions it has to be fabricated out of two sheets of plywood.
     
  2. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Welcome to the forum.

    If this is a little "foredeck", the plywood thickness depends on the spacing of the supports below, it's fastened/glued to. A closely spaced set of fore and aft stringers will permit thin plywood, commonly 1/4". More widely spaced stringers or athwart beams will require thicker plywood, say 3/8" or 1/2". Athwart beams and thicker plywood tends to be heavy and in the bow, this isn't a place to have very much additional weight, before it dramatically affects performance.

    I've done this recently on a 14' "tinny", but it wasn't a foredeck, but a casting deck, set down from the rail about 12". It permits the skipper to stand in the bow and work the shallows with a pole or fishing rod. I used a single "ring frame" of 1/4" plywood with a perimeter cleat, that permitted attaching to the hull shell. Over this was 5, 1x2's, evenly spaced, set on edge and notched into the ring frame's upper edge and landing on a cleat (another 1x2) glued to the hull shell's sides. Over this went a fitted piece of 1/4" plywood, glued and screwed in place. This was more than solid enough for the 220 pound skipper to stand on, mount a pedestal seat and even install a small fish well, into the casting deck.

    If it's just a little fore deck, 1/4" plywood over a couple of stringers will do, just in case you have to put a foot on it some day. The key is to think (and build) light, so the weight doesn't upset the balance of the boat too much.
     
  3. Speedqueen
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    Speedqueen Junior Member

    What the boat is a closed bow runabout, I just want to replace the aluminum bow cover with a beautiful wood bow cover. It will not be weight bearing more concerned with the flex of the boat and not having plywood ripped loose from the hull flexing.
     
  4. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Post an image or two of what you have, maybe with a sketch of what you have in mind.

    The little piece of aluminum sheet at the bow of most small tinny's, help tie the two rails together at the bow. You can skin it with a veneer or thin plywood if you like, possibly gluing it down to this aluminum piece. You can also replace the aluminum piece with all wood, though you'll want it to still tie the starboard rail to the port, with some solidity.
     
  5. Speedqueen
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    Speedqueen Junior Member

    I am going to have to figure out how to post pics, I only see the option of a photo on a website. I think I may wait till I have the basic frame of the bow in place.
     
  6. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    You can upload images from your computer, by using the "Go Advanced" button then using the "Manage Attachments" button on the next screen.
     
  7. Speedqueen
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    Speedqueen Junior Member

  8. Speedqueen
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    Speedqueen Junior Member

    That is the boat with the aluminum skin removed.
     
  9. Speedqueen
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    Speedqueen Junior Member

  10. Speedqueen
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    Speedqueen Junior Member

    That is the what supports the plywood.
     
  11. Speedqueen
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    Speedqueen Junior Member

    IMG_0709.JPG

    The original boat.
     
  12. Speedqueen
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    Speedqueen Junior Member

    It took some searching but I found a logger/mill that will make me the white oak 14' I need for the gunnels. Because of the length the wood will not be kiln dried. How long or how dry should I wait to seal the wood? Can I clamp the wood in place and let it dry? The gunnels will consist of 2 14' x 1-7/8 x 1/2" sandwiched on each side of the aluminum bow to stern.
     
  13. PAR
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    PAR Yacht Designer/Builder

    You don't need full length stock, you can simply scarf it to length. Your green lumber could take quite a while to dry enough to be stable. A lot depends on how it's stored and the environmental condisions it's stored in. If stickered up, outside, under cover, it'll be a few months at least. 12% moisture content is the goal, before sealing with epoxy, somewhat more, say 15% - 18% if using an alkyd or polyurethane sealer.
     

  14. Speedqueen
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    Speedqueen Junior Member

    I have climate control inside the shop. I can get the shop around 85-90 degrees and get the humidity down. The oak will be planed down to 1/2" x 1-7/8" so it should dry pretty good will go by weight to figure when it is ready. I had to go full length just for looks.
     
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