Transom replacement

Discussion in 'Boat Tips' started by cjb10876, Jun 17, 2006.

  1. cjb10876

    cjb10876 New Member

    Messages:
    59
    State:
    Pennsylvania
    I am thinking of replacing the transom of my '70 Grumman v-bottom. The board on there now is pretty soft near the bottom. I don't have a gas motor yet, just a 36 lb electric so I haven't been to worried about it. My question is when I replace it do I just use a pressure treated board cut to fit or do I need some kind of marine grade wood? Also, the bolts are all very rusty and I would like to replace them as well. It looks like there is some kind of sealer around the holes, is this just silicone like you would use for household plumbing or a special type for boating use? I may try and tackle it tommorow or I may put it off and head to a pond for some fishing. Either way I need to do it soon. Thanks for the help.
     
  2. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    get a nice white oak board and put a marine spar varnish or similar on it,
    seal any holes with 3m 5200. It comes in various size tubes. Around 15 dollars for a caulking gun size. This stuff doesnt mold or mildew and takes about a week to cure. Once its there its kinda tough to get off but you'll find no better sealer for a marine application.
    Keep in mind if you use stainless fasteners that stainless will rot out if you seal it.
    Stainless doesnt have the same corrosion resistant properties if its sealed from air.

    The problem with treated lumber in this case is that it is a soft wood. You need a good piece of hardwood to hang an outboard on.
     

  3. sgt_rob

    sgt_rob Member

    Messages:
    961
    State:
    Bossier City, LA
    Is the hull fiberglass or aluminum?
     
  4. cjb10876

    cjb10876 New Member

    Messages:
    59
    State:
    Pennsylvania
    The hull is Aluminum. If I don't use stainless what type of fasteners should I use?
     
  5. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    I would probally use stainless myself, I just wouldnt get carried away with sealing it.
    I would drill the holes in the wood and seal the inside edges of those holes and use some good fender washers.
     
  6. Pogo

    Pogo New Member

    Messages:
    96
    State:
    North Carolina
    Whenever I do a transom (and you can see discussions/samples I've posted previously), I use 3/4" Okuma Marine plywood, cut two pieces to rough shape, slightly over size and epoxy them into one piece 1 1/2" thick. Properly cured, the result is far stronger than any single piece of wood.

    After trimming to a precise fit, I then epoxy the entire transom, encapsulating it and bolt it into place using 5200 in each hole, stainless bolts, washers and elastic stop nuts.

    I prefer to line the entire transom area rather than just an 8" to 12" strip accross the transom top.

    Aluminum does not get along well with the chemicals used in pressure treated wood.

    My method is very likely "overkill" for your requirements, but I did just as I described on a 12' Alumacraft and had zero problems. Stained deep Walnut, it looked very good, too ..:smile2: .. I was accused of stealing someone's dining room table. Btw, alcohol based stains are very compatible with epoxy.

    The suggestions offered here are all good ones, so it's sorta your choice.
     
  7. cjb10876

    cjb10876 New Member

    Messages:
    59
    State:
    Pennsylvania
    Thanks guys. This is my first boat, so I'm new to working on this stuff. Nothing leaks so far, I'd like to keep it that way. How bad it it getting the 36 year old sealant around the existing bolts off, is that usualy a real pain? Does it just get scraped off with a paint scraper or something? Would that mar the aluminum?
     
  8. sgt_rob

    sgt_rob Member

    Messages:
    961
    State:
    Bossier City, LA
    I had my transom replaced because the weight of a 4-stroke destroyed it. I didn't use a splinter of wood; my transom is now 100% aluminum. The entire transom was fabricated using 1 3/4" X 4" Aluminum tubing and a plate of aluminum to join it all together. It was the creation of Mastermind Tony Howard.

    :0a26:
     
  9. sgt_rob

    sgt_rob Member

    Messages:
    961
    State:
    Bossier City, LA