It's Complicated
 

Ok after 2 years and 2 motors, I finally did the final pair myself and have some good numbers. 26 P, 98mph, 5950 rmp, ,.75:1 ratio, 17% slip.
All in all not too bad. I have much more throttle to go. I am just hitting the secondaries.
Here is the complicated part,, the porp above 85 is awesome. Trimmed at even (0) with Kaama drives. Although I don't loose touch with the water at the prop but, it makes for quite a ride. I have trimmed up, down and in between. I felt a little difference with some chop in the water. It was flat today.
I am thinking that I should look into a 5 blade. Maybe lab my 4's
Checked hull with straight edge and it is true. It has a single step. Props spin out, w 1" toe out. It also is a heavy boat and spins out easy, so I have to be on top of the throttles when taking off.
I would be happy for some ideas to rid me of the porp so I can enjoy the rest of the throttle.
Kaama Cat

Hey, we're neighbors.

I have set up a number of these older hulls.
They are touchy and often have straight shaft surface drives.
It will make more sense for us to discuss all the personalities you are experiencing on the phone.

Call us and we can go through a bunch of stuff.

Brett

Yup 5 blades. I went back to a 4b and I lost MPH. my boat tends to porpose to i think it is just the nature of the beast sort of like the "cat hop" After all the props i have tried and all of the testing i have done. it seems a 17.5 to an 18 diameter witha 18 to degree rake witha pitch to suit your HP is the trick on these drives

Hey, we're neighbors.http://www.bdoh.info/7.jpg

Thanks, it is nice to know that others have gone before me. I guess I get used to seeing those quarter million dollar boats running 100+ flat. May just be my expectations are a bit high of an 84 excal cat. Finally got the Hp and now understand that buying the boat is the cheap part, and feeding it is the other!
I thought 100 would have been faster, Uh Oh.

Blades, I will be in touch, I have family in BD and travel up north quite a bit, and get past the shop quite often. I know it will pull more rpm, on dyno they kept making power up to 7500 rpm.

Thanks again

I hope you work nights! Either that or you have a boating dependency ( 3:42am):cartman:

When you ran your trim down, did it help at all? It did not seem to make any change for me.
I thought about swapping sides with the props, any thoughts?
I heard it can make a hull sketchy, but a cat hull may not mind. It handles like a tank any way but I don't want to get in trouble from ignorance.