Would having the prop to deep cause the whole tunnel to lift out of the water?

[Mike Luszcz]

I was running my 30" Tunnel with SS K&B w/ Irwin Pipe, and X440 Prop this weekend, and the boat was literally out of the water and it cause major hopping across the pond..It did not want to blow over at all, but it would have just the prop in the water! Oh, it was fast, but very unstable. When I do a long turn the boat settles right in, and will do full speed turns with ease. Is my prop to deep? The center of the prop hub was about 1/2" below the sponsons. If I got the engine up more, would it help keep the sponsons planted?

 

[Duck899]

Yes, get the engine higher. The bottom of the hub or the bottom of the prop hub should be at least even with the riding surface. You only want the one blade of the prop to be in the water....any more and its drag.....

 

[Eric Bourlet]

Remember the props we run are going to try to run on top of the water. A good place to start is with the center of the prop even with the sponson bottoms. You may end up dropping it some but most likely no more than 1/4 ".A big part of tunnel setup is to get the CG correct too.

 

[Mike Luszcz]

Awesome, The more I thought about this, the more I was realizing that engine and prop, with the a boat so light would have to push that hull right out of the water! I think the boat is going to be a winner when its all said and done. (I don't race, but it will be a fun boat to run! )

The CG is pretty good as the boat seems very flat and even when the hull is totally out of the water doesn't seem to want to blow over. I cannot wait for the weekend to try out a new setup!

Thanks everyone, Mike