engine shaft length

Discussion in 'Outboards' started by killertrance, Sep 17, 2006.

  1. killertrance
    Joined: Sep 2006
    Posts: 7
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: blackpool

    killertrance Junior Member

    hi,i have a cjr 14 fishing boat and just aquired a standard shaft engine for it.the length of the engine from transome bracket to middle of prop is 24 inches,the length of my transome is 23 inches,the prop is just below boat.....is this ok??????????thanx for ure help in advance,regards,jeff oh forgot to add,the cavitation plate is very very near the bottom of the transome,not half way up or anything
     
  2. marshmat
    Joined: Apr 2005
    Posts: 4,127
    Likes: 149, Points: 63, Legacy Rep: 2043
    Location: Ontario

    marshmat Senior Member

    The only measurements you need to care about here are:
    Transom height, measured vertically from the hull bottom to the point where the motor bracket would hook over
    Shaft length, measured vertically from the inside corner of the motor's mounting bracket to the antiventilation plate (the big one above the prop)
    Standard lengths are 15", 20" and 25". The plate should be level with the bottom of the hull, give or take an inch.
    Too long a shaft will cause very sluggish performance. Too short and the prop (and cooling system) will suck air when you accelerate.
     
  3. Frosty

    Frosty Previous Member

    hey killer, Where yer going to launch that --Stanah car park? or little Bispham.
     
  4. killertrance
    Joined: Sep 2006
    Posts: 7
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: blackpool

    killertrance Junior Member

    both i think......lol
     
  5. fish is a fish
    Joined: Nov 2006
    Posts: 10
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: san diego Ca.

    fish is a fish Junior Member


  6. ted655
    Joined: May 2003
    Posts: 640
    Likes: 14, Points: 0, Legacy Rep: 122
    Location: Butte La Rose, LA.

    ted655 Senior Member

    The cavatation plate on the motor should be flush with bottom of hull, plus or minus 1"
    A long shaft CAN be run on a short transom boat IF absolutely necessary. A short shaft CANNOT be used on a high transom.
    A jackplate may aid in a "perfect" installation + help get the hull on plane faster (if it's a planing hull).
     
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.