Question about transon height

Discussion in 'Boat Tips' started by cjb10876, Mar 28, 2006.

  1. cjb10876

    cjb10876 New Member

    Messages:
    59
    State:
    Pennsylvania
    This is my first boat, and i've never set one up before, so I have a question about what gas motor i'll need when i get one. The boat is a Grumman 14' V bottom. I have an old Min Kota 65C electric as the sole motor (aside from my passenger and paddles). Assuming i'm measuring right ( bottom center of hull to top of transom) it looks to be 16.5" transom height. Would I use a 15" short shaft outboard or do I need to look for a 20" long shaft? Does the prop need to be lower than the bottom of the hull to get good water flow through it? I assume that's why they make tunnel hull boats, to provide a clear shot to the prop without interference from the hull.
     
  2. TeamCatHazzard

    TeamCatHazzard New Member

    Messages:
    517
    State:
    Illinois
    Yes the prop needs to be below the bottom of the hull to get water unless its a jet or tunnel hull. I would think that it sounds like you would need to get a longshaft, but someone else on here can tell you for sure but that is what I think.
     

  3. slabmaster

    slabmaster New Member

    Messages:
    719
    State:
    missouri
    mercury says 14 to 17 inch transom takes short shaft. yamaha says same thing. you can use a long shaft motor on a short transom boat but you will increase drag and steering will be a little tougher.
     
  4. cjb10876

    cjb10876 New Member

    Messages:
    59
    State:
    Pennsylvania
    How do the outboard manufacturers measure their motors? Do they measure 15" (or 20") as the length of the lower unit or is that from the transom mounting clamp to the prop centerline or some other measurement? Is this something that varies from one manufacturer to the next or is it standardized? Thanks for the info so far.
     
  5. Chanellocked

    Chanellocked New Member

    Messages:
    108
    State:
    Lake St. Louis, MO
    They anti-cavitation plate(just above the prop) should be about 1" below the bottom on the transom, a short shaft outboard should do you just fine:thumbsup:
     
  6. duxsrus

    duxsrus New Member

    Messages:
    1,014
    State:
    SW Ohio
    Yup, you need a short shaft motor. The variances between the hulls and motors can usually be overcome by the different mounting holes on the outboard. I've always seen the cavitation plate even with the bottom of the hull.
     
  7. Fordman

    Fordman New Member

    Messages:
    90
    State:
    Oklahoma City, Oklahoma
    A short shaft motor will work just fine.
     
  8. cjb10876

    cjb10876 New Member

    Messages:
    59
    State:
    Pennsylvania
    thankks guys, i'll keep my eyes open for a deal on a short shaft motor.
     
  9. mississippicatfisher

    mississippicatfisher New Member

    Messages:
    19
    State:
    Pontotoc, Mississippi
    i got a boat one time and it had a short shaft motor with a high transon needless to say it didnt turn out to good, worked fine till i turned sharp and it couldnt get water to cool and it blew the motor