After many test this year with Throttle-Up with both Hydro`s and Bravo
props we could not get the boat to lower the slip, this boat will not run will with a prop less than 15 1/4 diameter. I sked Mat and Julie to order me the old style Hydromotive 15 1/2 diameter cleaver style four banger and when I installed it my slip was gone, I went from 20% slip to around 10 with the bigger diameter having a great whole shot and running less R` and still running as fast as before. I had to trim my drive to #5 with no tabs to get WOT now I set my drive in #2,3 and my tabs down to #2,3 and now I have great handle on the boat. In the picture below drive at #2 and tabs at #3
I will be selling all my bravo props for anyone intrested I have a 28, 30 and Throttle-Up labbed 31 in new condition.

Albert

My x is the same as grifs best I can measure my propshaft is 3 1/4 inches below the boat .I like Alberts comment about slip the only prop that brought slip down was the 5 blade .I have never experemented with the larger diamater hydro .I have a 31 LH hydro Im gona test a little but I afraid of the load it will put on the drive. Grif Roster tail who cares mine throws one from hell but the boat goes faster with the drive up one inch from yours and rides better .Any racer will tell you less drive in water faster boat but he never owned a pantera gota keep nose up .So the Q to ponder is how to keep drive out of water and nose up 5-6 blade prop seems most likely answer.But I raised x one more inch and did not pick up any speed kept nose up good not great but I didnt have mike build that much bow lift in it . Mistake. New plan keep diamater build bow lift and raise drive . Im tired of typeing

B, sounds like you've got a lot more power than me if you're gonna be testing a 31". I'm running a 26". That is probably helping you carry the bow more also. As far as the rooster tail, I kinda liked it. The problem was trimming up would increase the rooster and the bow wouldn't lift. All that would happen is my rpms went up and prop slip went up.

I've looked for larger diameter props, but the only ones I've found are only made in 28" and up.

I'll have my eye out for a 5 blade. I was thinking that with it, I could raise the drive back up.

My new creation is comeing together 1471 littlefield 565 inch with some big heads intercooled .My curent 555ci only has a 1071 littlefield with Brodex no2s . Its in the works ??

Ithink you can get that boat hooked up and get the spacer out Griff .In the word of the famous crocidile dunde thats no rooster tail.