Transom Height for Twin Outboards

Apollo HT

Cadet
Joined
Feb 26, 2005
Messages
7
I am converting my old OMC stringer sterndrive setup, to a twin outboard setup. I will be designing my own floatation based outboard bracket, but need some help with what height to set the bracket at.<br /><br />I understand a single outboard height should be set so the cavitation plate is even with the bottom of the keel (have a 22 degree deadrise hull at the transom). But for a twin setup, should the outboards sit a little higher, keeping the cavitation plate even with the bottom of the hull? Also, if the outboards were set higher then the keel of the boat, is there a possibility a prop could come out of the water on a turn...obviously yes...but what rule of thumb is used for setting up twin outboards on a "modified-vee" hull?
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Transom Height for Twin Outboards

You figured it out just right, Apollo.<br /><br />Anti-ventilation plates (usually called cavitation plates) should be even with the part of the bottom immediately in front of them.<br /><br />Welcome to iboats, and good luck. :)
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Transom Height for Twin Outboards

Remember the rule of thumb for set back too. For every 5" you go back you can go up 1". Place the motors according to the way water comes off the hull. If there are lifting strakes you want to center the motors on them if possible.
 
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