military bidge boat the transom has no angle what is the best way to attach outboard?

Discussion in 'Metal Boat Building' started by o2bfishn, May 29, 2008.

  1. o2bfishn
    Joined: May 2008
    Posts: 1
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: west virginia

    o2bfishn New Member

    I have a military bridge boat that is 19 feet long 7 feet wide and 24 inch deep at the transom. Plus the transom is 90 degrees.
    These boat were designed to be a float bridge. 2 boats bolted together by the transom and bridge road bed attached on top. If you have seen the movie "kelly's hero's" starring Clint Eastwood they drove a tank over one.
    The problem I have is: What is the best way to put a motor on the back with such a steep angle and height.
    I have attched some pictures from a Vietnam web site that shows 2 50 horse power motors on it.
    Thank you for your idea's

    Attached Files:

  2. marshmat
    Joined: Apr 2005
    Posts: 4,127
    Likes: 148, Points: 63, Legacy Rep: 2043
    Location: Ontario

    marshmat Senior Member

    Well, first of all, welcome to :)

    Most outboards you find now will probably be set up for a transom raked aft around twelve degrees, give or take a few degrees. Sterndrives are in the same ballpark; jet drives are generally available in 0 or 5 degrees.

    Depending on the outboard, its lowest trim setting might give an acceptable thrust line (ie, near parallel to the bottom) with the current, 0-degree transom. Other outboards might trim out too much even fully tucked in. If that's the case for your chosen setup, probably the easiest solution would be to fabricate a setback bracket at a suitable angle, bolt it to the transom, and clamp/bolt the outboard to the bracket. In steel this could be done for less than a hundred bucks if you can cut/weld it yourself; fibreglass is also an option. This way, you don't compromise the original boat (esp. its structural integrity) at all, and you have more freedom to optimize the motor placement.
  3. charmc
    Joined: Jan 2007
    Posts: 2,391
    Likes: 78, Points: 0, Legacy Rep: 840
    Location: FL, USA

    charmc Senior Member

    Welcome aboard!

    A setback mounting bracket is probably your best bet, allowing you maximum flexibility. Matt has summarized the details very well.

    Good luck with your project.

  4. Lt. Holden
    Joined: Sep 2007
    Posts: 137
    Likes: 1, Points: 0, Legacy Rep: 20
    Location: Western Massachusetts

    Lt. Holden Senior Member

    Does it have the M-60 on it, Cool!
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.