Transom replacement part 1

Discussion in 'Boat Modification Journal' started by justwannano, May 12, 2008.

  1. justwannano

    justwannano Active Member

    Messages:
    1,003
    State:
    SE Iowa
    The transom was still complete that day when I decided to test it.
    10 seconds later I had a chunk of it in my hand.
    Dry rot from years of sitting in the yard covered with a tarp.
    The bottom was rotten but the top still had some strength.
    I decided to try reinforcing it with an oak 2X6.
    See Pix 1[​IMG]


    Well it worked. Several trips to the river and there were no problems but that rotten transom still needed to be replaced.
    Motor problems cut short last years fishing which was probably a good thing of sorts.
    Well now the motor is repaired and I still have a rotten transom.
    Some of you probably recall answering my seemingly endless questions on best ways to go about replacing a transom. . I would like to thank all of you for your input.
    After considering all that input and adding some hard earned ideas of my own here is what I came up with.

    I’ve considered solid oak and plywood. I really favored oak and actually bought a newly rough cut and cured piece that was supposed to be 1 1/8 inches thick. Well its not.
    One end is slightly over 15/16 and the other a shade over 1 1/16. It should be 1 ¼.
    So I would need to buy another piece and pay to have both pieces planed to a total of
    1 ¼. Then glue them together.
    Enter plan 2
    A piece of ¾ and a piece of ½ cdx plywood glued together.
    See pix 2.[​IMG]

    When you buy plywood the thickness is a nominal figure. Its not really ½ or ¾ .Well when I checked the thickness before gluing it was .090 under the 1 ¼ that I needed. Not the best of situations but something I can deal with. An aluminum shim of .080 should do the trick. I figure its best to keep the thickness extremely close to the original so there is little stress on the aluminum transom braces and corresponding rivets.

    The glue
    I actually favored the idea of using epoxy (fiberglass resin) as the glue to hold the 2 wood transom pieces together. Then coat the whole transom with resin to make it waterproof. Then I got to wondering how well the resin was going to react to being cut with a saw to the dimensions needed. Then it was going to be drilled for bolts too. What I didn’t need
     

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  2. justwannano

    justwannano Active Member

    Messages:
    1,003
    State:
    SE Iowa
    was tiny cracks in the glue to take up moisture. Not only that but everywhere I looked locally didn’t have epoxy.
    So OK the next problem was what glue to use. I did all kinds of searching to find waterproof glue and finally picked up a bottle of Gorilla Glue. Says right there on the bottle 100% waterproof. What more could I ask?
    Applying it was simple. Squeeze some on one surface and using a wide putty knife smooth it to a thin even solid surface.
    I had cut the pieces to be glued slightly oversize so I could screw it together outside the actual transom piece so as not to have any needless holes in the transom.
    I also shot brads every 3 inches top and bottom.
    Pix 2 shows screwed and clamped oversized transom piece.
    Gorilla glue works best at a temp of 68 to 130 degrees. The weather wasn’t cooperating and I don’t have a heated garage or basement so you’ll probably notice that is a dining room table in the background of the picture. My wife said it was OK .lol

    [​IMG]

    Pix 3
    My choice of coatings was rather simple actually.
    Back when I was in High school I worked a couple of weekends with our neighbor. A professional house painter.
    One weekend my job was to paint the front and back porches and the steps leading to an upstairs apartment. Got to thinking about that. Simple porch enamel is waterproof, tough as nails, and not affected by sunlight or weather. Hell you can walk on it.
    Pix 4[​IMG]

    I had also decided on using stainless steel bolts but after checking the price I rethought that decision too.
    You folks that have worked in a factory have probably noticed those black button head socket cap screws that custom made aluminum factory equipment is held together with. Well those things are#10 hardness. That means they won’t easily rust. With that black coating it makes them a good choice for joining aluminum and wood.
    50 stainless stove bolts was going to cost me over $50.00. The cost of 100 black button head socket cap screws is $35.00.
    Pix 5
     

    Attached Files:


  3. justwannano

    justwannano Active Member

    Messages:
    1,003
    State:
    SE Iowa
    [​IMG]
     

    Attached Files:

  4. justwannano

    justwannano Active Member

    Messages:
    1,003
    State:
    SE Iowa

    Disassembly
    We tried drilling out the rivets and found a good sharp cold chisel did a neater quicker job. We knocked the rivets out with a pin punch.
    My brother was an Air Force air frame mechanic and really knows his stuff. I just let him do his thing but it wasn’t difficult.
    Pix 6
    [​IMG]

    The old transom
    Pix 7
    [​IMG]

    Back of boat with corners and wood removed.
    Pix 8
    [​IMG]

    The new transom in place. The new sandwiched piece of plywood was not quite the 1 ¼ we needed so we slipped a piece of aluminum plate in to take up the space. That way the strain on the rivets holding the braces on the bottom of the boat would be the same as before.
    Pix 9

    Bolting it back together.
    The easy part
     

    Attached Files:

  5. justwannano

    justwannano Active Member

    Messages:
    1,003
    State:
    SE Iowa
    [​IMG][​IMG]
     

    Attached Files:

  6. justwannano

    justwannano Active Member

    Messages:
    1,003
    State:
    SE Iowa
    Well there you have it.
    A step by step walk through a transom replacement.
    I hope this helps relieve any apprehension you may have in tackling your own transom replacement when its needed.

    Cya on the river
    Just