re powering a 16 foot hydroplane

Discussion in 'Propulsion' started by hydroplanedude, Sep 15, 2012.

  1. hydroplanedude
    Joined: Sep 2012
    Posts: 1
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Vashon Island

    hydroplanedude New Member

    Does anyone know why I can't put an inline 4 cyl motorcycle engine complete with with 5 speed transmission, hooking the drive shaft to the prop of a 16 foot hydroplane??? I was thinking of a fuel injected water cooled job with a cooling fan in the nose of the boat. I am a certified auto mechanic, but the water has different needs. Will I run into problems??? Suggestions, and experiences to share???
    Roger
     
  2. Ike
    Joined: Apr 2006
    Posts: 2,404
    Likes: 283, Points: 83, Legacy Rep: 1669
    Location: Washington

    Ike Senior Member

    you won't need the transmission. You may need a reduction gear though to reduce the rpms.
     
  3. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 476, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    The transmission can be used, but you'll only use only one gear. In fact, a common back yard trans was the old truck 3 speed (343 Saginaw) bolted to a small block Chevy. The trans was disassembled and everything removed except reverse and first. The gear you use will depend on how fast you spin the engine and props for the speed range you desire. The small blocks liked 2.5:1 which worked out just fine with these old trannies.

    Motorcycle engines aren't designed for this type of "duty cycle" so it'll have a poorly matched cam and will not live long, if asked to act like a boat motor, but you can have some fun for a while. This coupled with the need for spark arrested electrics and intake, or a completely open engine bay, may make you reconsider the idea.
     
Loading...
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.