Rebuilding a Seabreeze 1900

Discussion in 'Boatbuilding' started by Brian Peterson, Oct 26, 2011.

  1. Brian Peterson
    Joined: Oct 2011
    Posts: 10
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Westbrook, Maine

    Brian Peterson Junior Member

    I recently acquired a LynCraft Seabreeze 1900 Contessa runabout - 17-foot long, 84 inch beam. It is one of the original ones, built 1958-60, and is in pretty bad shape. It has been outside uncovered for at least 8 years, and is all rotted out, but it's too cute to get rid of. I have started a phone relationship with the son of the builder, and he says it might be the last one extant. He has not seen my model since 1965.

    This boat has 3 2"x6"x12' stringers with 6 4" half round stiffeners of FG in various places on the hull. The wooden stringers have had a light coat of FG on them, but it is rotted out, as is the wood- One can literally rip off a piece by hand and squeeze out water.

    I have removed the bulkhead and deck, made of 3/4" plywood.

    (I should mention that I also have a 25 foot Oday, and can do FG, gelcoat, epoxy, and layup.)


    SO, here is where I need some advice! From long reading of this site (which is fantastic, by the way) I gather that there are a few ways to do things.

    I want to remake the stringers: One piece 2x? douglas fir, epoxied to seal, then 8oz cloth all around, before epoxying to the hull, filleted, and tabbed, with extra 2-3 layers over ?

    OR, make the stringers out of 3/4 marine plywood, epoxying them together with 8 0z cloth between the layers, joints staggered, for a total thickness of 2 1/4 ". Seal with epoxy, then epoxy to hull, fillet, and cover with 2-4 layers of cloth, tabbed in. Maybe 3/4" thick flat tops 4" wide?

    To avoid hard points 1/8" foam rope under the stringers? Or just epoxy ?

    I'd like to add some extra cross stringers, for solidity and strength, but don't know if that is a good idea. Others in here have said it is.

    The sole will be 3/4 " marine ply epoxied for seal, cloth on the upside, set in place on the stringers with thickened epoxy, SS screws into the stringers. A
    1/2" space between the sole plate and hull, then tabbed in with 45/45 biax (2-3 layers), then cloth over to seal and smooth. Same for the bulkhead. I'm thinking about gelcoating it all also, versus paint.

    Reference the hull, it's a little thin for my tastes (1-8" - 3/32nds") so I am planning on at least 2 layers of cloth, RESINED in , full length, before the stringers go in.

    The transom literally had an ant farm and earthworms in it. That was all cut and gouged out. That will be 2 layers of epoxied 3/4" ply with another 1/2" layer to make original depth. Cloth over that - 3-4 layers, resijn, cloth and gelcoat to finish.

    I will probably put a 50-65 horse motor on it, so am looking for an older version of whatever I can find.....

    I estimate about 500 lbs total weight, but that is about what I took out in waterlogged crap.

    Does any of this make sense at all? Too much? Not enough? I'm open dto any suggestions, so let me have it! Thanks in advance...

    Brian Peterson
     

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    Last edited: Oct 26, 2011
  2. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 471, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Most of your plan seems well researched, though after nearly a half a century, you'd have to expect these sort of issues.

    Your boat has a thick hull shell laminate and should hold it's shape fairly well, but it would be wise to insure this remains the way it's supposed to be, with a few athwart braces and likely some sort of cradle. Letting her sit on her bottom in the yard is just introducing hull distortions that you don't want to build back into the hull shape.

    The cradle can be very simply made from some 2x4's and/or 2x6's as a longitudinal set of braces. From which plywood forms, cut to the athwart shapes spaced along the hull's length, vertically are fixed. Say 3 or 4 equally spaced vertical hull supports will do. Between the rails, place a couple of 2x4's to insure the hull sides don't want to fold inward, as you walk around inside her. Once she's firmed up, you can start your rebuild process.

    3/4" plywood for the sole is way too thick and heavy. You want to think light, but strong on this old girl. 1/2" plywood over a basic support system of stringers and cross braces will be more then enough. Bond the sole to the tops of the stringers as planned and tab into the hull shell with 4 layers of biax. Make sure you have a healthy amount of over lap on the hull shell and plywood.

    If you use plywood for the stringers, you'll need extra heavy tabbing. If you use solid wood for them, then your tabbing can be lighter as the solid wood has 40% more longitudinal stiffness then the plywood and bears much of the loading.

    The transom should be 2 layers of 3/4" plywood, bonded and tabbed or 3 layers of 1/2" (which is stronger).

    Tabbing is critical to long term success. Make several inch contact patches where anything gets tabbed onto the hull shell. 1/2" plywood needs 2 layers of 12 ounce biax on both sides to be just barely strong enough. If you can only get at one side, then all the fabric weight should be on that side. You can't screw up if you use too much tabbing, but you can if you don't use enough, so error on the too much side.

    I've got to run, but I'll check back later to see where this thread is. Also check previous threads (there are thousands) for the same issues you're facing, using the search tool.
     
  3. Brian Peterson
    Joined: Oct 2011
    Posts: 10
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Westbrook, Maine

    Brian Peterson Junior Member

    Thanks, PAR

    Thanks for the input- not to beat this to death, but here are a couple more questions - I have been reading the archives, in some depth, and most of them, if not all, say to "recreate what was there - it's there for a reason" -- the sole and all of the plywood is of 3/4 "- I get that 1/2" would be good and light , but it's not the "original" material. Half inch for a sole seems a bit thin.

    Reference the frame for the hull, to make sure it's not askew, how do I know it's NOT askew when I get it done? ?

    Since the photo I posted, I've raised the stern level with the bow, blocking it up with concrete blocks and 2x6s, set under the chine. I also have 2x6 along the keel, so the whole boat is supported along its length. I was thinking that the cabin top would keep the hull from expanding out, but was uncertain about the longitudinal aspect of the whole thing. There is only about 4.5 feet not held together by the cabin top or the motor mount "tray". I get the idea of the athwart spacers, but am unsure of their need.

    Assuming that the blocking / planking for the keel is not doing its job, how do I make sure it's all as atraight as it should be? I'm leery of supporting it wrongly, and then building that error into the hull......

    I've taken VERY careful measurements between various holes in the deck / cabin top, to make sure nothing gets too far out of whack.

    I am also thinking of installing a bilge ventilation system -- a solar fan than blows air into the bow area, then out the stern, probably with a 12V computer fan arrangement. I'd have a vertical "chimney" in one corner of the stern, with a down-facing exit port, kind of like a gas ventilation tube ....what with that and a few lubber holes in the right place, I think I could keep the moisture down....

    I read how you use Xmas wrapping tubes for stiffeners- that is what I have planned for the hull in the areas denoted by the colored lines. The blue would be wood , the lavender, FG over the half tubes.

    The hull is not 3/8 -1/2 " thick, as far as I can tell. It's maybe a 1/4" to 1/8" . I'd really like to put a couple layers of mat / biax down before stiffening.

    Reference the stringers- DO keep them off the hull with 1/8" rope? ---or just embed in epoxy? The archives say both- I will defer to you!

    thanks again- this is certainly a learning experience....
     

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    Last edited: Nov 2, 2011
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