This is the boat that I am thinking of. Fountain used to manufacture it. It was then contracted to another builder who still builds it in Mississippi.

I have one of the props in the shop they are currently running and we are working with them now to manufacture propellers for this boat. It will be a few months before we have the prototype finished and then we will begin testing on the boat.

Try extending the bottom cavation fin on the drives 2 or 3 inches. I had the same problem. I have different boat and set up but it worked well for me.

Thanks Dwane i will try that.

By going from 3A's to 4's, you raised the propshaft height about 3inches. I think you'd be luck to get on plane with 6 blades, that propshaft height and that much weight. Not to mention, your propslip will probably be very high.

Do anybody have a good guess what will happend if i try 17,5x28 4-blade cleavers i can get them pretty cheap.

Is there a reason you don't want to go back to 3A's and get the drive back in the water for your hull set-up ?

Have any pictures of your boat ?

Cougarman

Markku you know the 4,s are alot shorter then the 3,s. did you mount the gimbles in the same hole ? My 30 super was hard to plane off. I had MRD make a custom cavitation plate for the drive and that took plaining rpm down to 3500 then added a dolphin ,looks kind of funny but the rpm is under 3000 to get it on plane . My boats for sale in the superboat forum maybe a picture will help you see what it looks like. check it out. Griffs rite on the money. You need more blades very pricey. I bet 2 inch spacers would help greatly. They can be had fairly cheap.

Yes here are some pictures

spacers, 4 bld's, and a cavplate similiar to the one used with imco shorties just designed for the 4 will work well. i had a similiar issue when rerigging an old sonic from 3's to 4's.

Are you using the trim tabs to get on plane? Sometimes the tabs will take the water away from the prop and you won't be able to get on plane.

Mark