Motor height for non planing Mac 26X

Discussion in 'Sailboats' started by RonR, Jul 10, 2008.

  1. RonR
    Joined: May 2008
    Posts: 28
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Alabama

    RonR Junior Member

    Does anyone know the optimum anti-cav. plate height below the hull for my MacGregor 26X?

    Most of what I read pertains to boats wanting to get up on plane, and generally advise the anti-cavitation plate to be 1 1/2 inches below the hull.

    In my case the Honda 20 hp isn't powerful enough to put me up on plane, which is fine. That being the case, could I put the motor lower down. I believe I have trim set properly, but still see wash starting about 10 ft behind when running 7-8 knots.

    Thanks....
     
  2. rwatson
    Joined: Aug 2007
    Posts: 5,811
    Likes: 269, Points: 83, Legacy Rep: 1749
    Location: Tasmania,Australia

    rwatson Senior Member

    I dont beleive cavitation plates will do anything for you except create unwanted drag with a 20hp.
    Even a 50 wont really 'totally plane' a mac hull, but it will push it along more efficiently.
    It would be handy to see a picture of the 'wash' you mention.
    How far down is the prop from the waterline ?
     
  3. RonR
    Joined: May 2008
    Posts: 28
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Alabama

    RonR Junior Member

    Hi RW
    The c/l of the 9.0" dia. prop looks to be about 15" below the waterline. The drop from the waterline down to the hull is approx. 5". I am thinking that if I decide to extend the prop (and rudders) back about 12" from the transom, perhaps I could also drop the prop. a bit more. No photos yet, but still working on that........Cheers

    PS. I don't really care about ever getting up on plane with a puny 20hp, but just looking for the best efficiency.
     
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.