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Optimum Motor Height

Posted: September 18th, 2003, 4:38 pm
by CSMarine
What is the way to measure an outboard motor to figure if it will work on a boat? Transom height on the boat is 18 inches from top of transom to bottom of center keel.

Posted: September 18th, 2003, 5:30 pm
by wevans
I allways measure from the top bolt hole to the cavitation plate and and where I'm gonna drill my top hole to the center keel :D The cavitation plate should be even with the keel or can be just below it :thumbup:

Posted: September 20th, 2003, 5:21 am
by tin can
There is no way of knowing until you mount the motor and run the boat. The cavitation plate in line with the keel is a starting place. The cavitation plate should run right at the surface with the boat under power. It's a trial and error process.

Posted: September 22nd, 2003, 7:36 am
by CSMarine
I've got a small 14' boat I'm rigging for skinny water. It's 18" to the bottom of the center keel. Does that mean I need a 20" shaft motor?
Motors come in 15",20", and 25" shafts don't they?

Posted: September 23rd, 2003, 6:22 am
by tin can
You do need a 20" shaft. Sounds like a jack plate would be helpful if you're going to have to start out raising the motor 2". You might want to look at the Mini- Jack plate that Bob's sells.

http://www.bobsmachine.com/

Posted: September 23rd, 2003, 7:43 am
by CSMarine
TC, I've looked at a couple different rigs to raise and lower the motor. Still in the planning stages right now. Don't have a motor yet. Spending all my play money getting my place over at Keaton set up. The bottom of this boat is different than any I've owned before. It was called a "triple keel" boat. All three Keels run real pronounced all the way to the transom. There is 4 inches from bottom of keel to bottom of hull on all three keels at the transon. Maybe an early try at a tunnel hull. It's a 1984.

Posted: September 24th, 2003, 6:47 am
by tin can
CS, sounds like an interesting boat. I'd like to see it when you're done. I wouldn't mind riding in it, if ya happen to have an open seat sometime. :) Good luck with the rigging.

Posted: September 24th, 2003, 7:35 am
by CSMarine
Thanks TC. I'll save you a seat. :thumbup: