Jack plate/set back with a jet outboard?

[oregonducker]

Will the potential jack plate benefits you get with a prop be similar with a jet? I'm replacing my prop motor with jet and am trying to decide if I should just raise the transom or go with a jack plate.

 

[tashasdaddy]

Re: Jack plate/set back with a jet outboard?

not ignoring you, but i have no idea.

 

[Lone Duck]

Re: Jack plate/set back with a jet outboard?

yes; set it up buy experimenting a little . You want the jetfoot to sit in the pressure wave . depending on how much pressure wave your hull produces, the foot should ride 6 to 8" of the stern and anywhere from 1" below to 1" above the hull bottom. Once you get the setting on flat water. Try it in a light chop. If it cavitates then drop it down 1/4" at a time till you find the best for your boat. If you have skegs on your hull bottom you may have a cavitation problem no matter where you set it. hull must have no protrusions in line with foot for at least 3' forward of foot. Also remember that you will have a 30% loss of in the water hp. with a jet foot.

 

[oregonducker]

Re: Jack plate/set back with a jet outboard?

Thanks for the info. Sounds like a jack plate will be the way to go. I've heard tuning a jet to match the boat is a bit of an art. Jet outboards are quite common around here so help is nearby if I need it. I'm moving up from a 40 hp prop to a 60 hp jet so I should stay about the same with actual hp. Thanks again.

 

[Lone Duck]

Re: Jack plate/set back with a jet outboard?

Your welcome; I forgot to mention that the best angle of the transom for a jet is 15% . you could set your jack plate to that angle . If you want you could go to the archives and look at the hunky dory by bob lutley. I did not use a jack plate because I have a tunnel.

 

[longshanks]

Re: Jack plate/set back with a jet outboard?

to reduce cavitation, and change the performance of that jet intake, try getting your hands on some 'intake fins'. I made some up for my motor, out of 1/8" aluminum, and they improve the performance of the jet motor all around. I think they would be helpful in the application you describe.

 

[Lone Duck]

Re: Jack plate/set back with a jet outboard?

Longshanks;
You are right. I forgot to tell him thay. I got mine at a merc. dealer. They sure help the steering and less cavitation. Steering works a little better at slow speeds.

 

[oregonducker]

Re: Jack plate/set back with a jet outboard?

Intake fins? New to me. Got pics or a link to a seller? I'm going to check with a boat guy here about putting a tunnel in as well. See what that costs compared to using a jack plate.

 

[oregonducker]

Re: Jack plate/set back with a jet outboard?

Nevermind . . . found a site.