Proper engine height on 18'??

Hey gang, I just spent a year and $25+k on restoring a 1972 18' Dyne and I'm ready to hang the motor on a new transom. Any suggestions on height? I'm hanging a 2001 Yamaha 200 VMax. The Yamaha book says "Mount the outboard so the anti-cavitation plate is about 5 in. above the bottom of the boat." That, to me, makes no logical sense. I think it should be even with the bottom of the boat. If it was 5" higher, it was cavitate. No? thanks for your input.

 

Assuming you have a 20" transom like my 72 mount it with the cavitation plate even with the bottom. How about some pics?

 

Please post pictures of your finished project.
I would love to see them. Spending over 25K this thing should be sweet......

Bob

 

I believe the transom is 21"
i will share a whole progression of photos when i have a chance but here's some pics with fiberglass done and prior to interior...

 

21 should be even, it is on mine. Given that the water rises after it comes out from under the boat, a little higher might work If your 21 works out that way.

Watch what happens to the cav plate as you trim in. I would also use a wedge for more in trim.

 

That boat needs to sit on bunks IMO.

jim

 

Yes bunks are much better than rollers. Rollers are hook manufacturers.

 

Wow, what a beautiful job, Steve!!!!!

 

I just reread your original post. It says 5 inches. When I first read it I thought it said .5 inch

The 5 inch number refers to high performance boats which run a surface piercing prop. My high performance boat ran the PROP SHAFT CENTERLINE at 3/4 inch ABOVE THE BOTTOM.

It would cavitate on takeoff until it hooked up. The prop was designed to run that high. It would be totally unsatisfactory on a ski boat.

jim