Optimum Motor Height

Post by **CSMarine** » September 18th, 2003, 4:38 pm

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.

Post by **wevans** » September 18th, 2003, 5:30 pm

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

The cavitation plate should be even with the keel or can be just below it

Post by **tin can** » September 20th, 2003, 5:21 am

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.

Post by **CSMarine** » September 22nd, 2003, 7:36 am

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?

Post by **tin can** » September 23rd, 2003, 6:22 am

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/

Post by **CSMarine** » September 23rd, 2003, 7:43 am

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.

Post by **tin can** » September 24th, 2003, 6:47 am

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.

Post by **CSMarine** » September 24th, 2003, 7:35 am

Thanks TC. I'll save you a seat.