Engine height for V bottom

**A Mosny** · 03-15-2014

Many years ago I set up a small tunnel hull with a 75 hp Johnson and the rule of thumb was to raise the prop shaft 1" above the bottom of the boat. This worked well and I won a few races. I'm now building a small V bottom to sport around in the river. Since no experience with V bottom set up, my question is how high or low should the prop shaft be in relation to the bottom of the boat for a V bottom set up? This boat is a shallower V design and the same 75 Johnson will be the power but included will be a 6" set back due to a trim/tilt bracket being installed. My goal is to be quick down the river but still maintain some turn without blowing out the prop. Comments on prop pitch selection are also welcome. Any feedback is appreciated.

Thanks Anthony

**Ron Hill** · 03-15-2014

In the old days, we didn't have bottom water pick up nose cones, we didn't have transom jacks, we didn't have power trim and we had three blade propellers. Now there are more prop combinations than I can keep up with, three, four and five blades. I guess if there IS a "Rule of THUMB", it would be try something (Document it), try something else. The, try something else! Ask questions on BRF!

I know many a Vee Bottom running the prop shaft 2" above the bottom on a three cylinder motor.

ADD: Tunnel run the prop shaft 3 inches up into the tunnels on some boats!

**Chairman** · 03-16-2014

My experience with small (35hp GT Pro) v-bottoms is jack it up as high as you can without losing water pressure. For a 31.8 OMC without low water pickup, that ends up with the prop shaft about 1.5" below the pad.

**A Mosny** · 03-16-2014

The "try something then try something else" is the same way we did it back in the 70's. On occasion was expensive when the idea crashed and burned and my buddies ragged me for weeks. From 1.5" below to 2" above gives a range to select a start then adjust from there. I know what you mean with regard to props....pitch, diameter, number of blades, exhaust hub or no hub. I'll be thinking and asking more questions to BRF about this topic. Thanks for the tips. Much appreciated.

**89HST** · 03-17-2014

What boat?

**A Mosny** · 03-17-2014

15' Panther. Narrow boat with shallow V.

**Ron Hill** · 03-19-2014

Hey Chairman, what transom height do you run on a GT PROP Vee Bottom with stock water ick ups?

**Chairman** · 03-20-2014

I've made mine 20" high. If you mount the motor directly on the motorboard, that turns out to be a reasonable height. If you add a jackplate with a few inches of setback, there's room to go up another inch or two.

**omcstratos** · 03-20-2014

Originally Posted by A Mosny

15' Panther. Narrow boat with shallow V.

I'm in the middle of a 13' panther right now. Do you have any pics of yours setup?

**A Mosny** · 03-20-2014

Chairman this seems to be the set up to start with. Transom has already been raised to support a long shaft which will put the shaft even with the bottom according to my tape measure. I'm sure there will be trials and adjustments to find a happy medium for getting out of the hole and turns without catching to much air or running hot. Comments are much appreciated.....Thanks