sterndrive, clearance

Discussion in 'Boat Design' started by Danielsan, Sep 14, 2005.

  1. Danielsan
    Joined: Jul 2004
    Posts: 255
    Likes: 0, Points: 16, Legacy Rep: 10
    Location: Belgium (Europe)

    Danielsan Amateur designer-builder?

    Hi to all,

    how much space do I need at the transom to mount a sterndrive? Let's say a bravo2 drive

    knowing the cavitation plate height falls toghter with the bottom of the hull.

    Is it necessary to trim the drive completely up in some case? As this would be my major concern.

    have a look at the sketch, if full trim up is not needed, I could make some kind of cavity in the rounded aft part giving me 45 deg left, right and 10-15 deg tilt up clearance?

    What clearance is needed to install the drive onto the boat?

    Thx
     

    Attached Files:

  2. crawdaddy031
    Joined: Sep 2005
    Posts: 15
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: DeLand on the St.Johns

    crawdaddy031 Junior Member

    Full up is not needed as long as you don't mind dragging the drive on the ground when you load onto the trailer or maybe your trailer will be high enough for good clearance when you hit a bump or dip in the roadway. Good luck with your project. Jim
     
  3. marshmat
    Joined: Apr 2005
    Posts: 4,127
    Likes: 149, Points: 63, Legacy Rep: 2043
    Location: Ontario

    marshmat Senior Member

    While you may never need full-up, it's a good idea to allow enough clearance to do so and to have full steering range when tilted up. I would simply cut out the swim platform in the area around the drive to give it enough room to tilt. I have had many occasions where I have needed to tilt a drive to the top stop- not necessarily trailering, but to get a boat off of logs, sandbars etc. or at docks with low water levels so the prop doesn't hit the bottom when the waves come up.
     
  4. Danielsan
    Joined: Jul 2004
    Posts: 255
    Likes: 0, Points: 16, Legacy Rep: 10
    Location: Belgium (Europe)

    Danielsan Amateur designer-builder?

    Sounds both like enough reasons to get some more room or put the transom more aft then it is now and use some kind of mobile swimplatform to extend the aft part.
     

  5. DPetersen
    Joined: Aug 2005
    Posts: 4
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Seattle, Wa

    DPetersen New Member

    Mercs X dimension (fromthe keel xsom intersection along the transom at 13 degrees to the input shaft centerline) is 14-1/8". Start there.

    As for drive clearance, you can buy tilt limiters that go inside the tilt cyclinders. Usually A guy wil have to cahnge a prop int he water and will want it to tip all the way up.

    I have used many Bravo 2s in design and installed a new on on my boat. I have a full 3d model of the drive that is accurate and shows the drive int he down position and turned lock to lock and also in the up position. Its handy if you want it write me. Its a Rhino file.

    Also, never us a 4 bladed stainless prop. Stick with the aluminum props. It will corrode the paint off of your skeg with or without the mercathode system set up. total BS, another fine problem for the end user from the brain children in Fond du lac. Why make merc cheaper and more reliable when you can add complicated systems that not only ignore users needs, they make it more prone to fail.

    Bravo two is the only good merc drive.



    Dave
     
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.