Alternative cat props
 

Ok, I got out over the weekend and was able to solve my water supply issues. The boat ran really well and other than a loose battery cable, we had no problems. Well at least while we were on the water. But that's another story. First a little background info:

26' Firehawk cat (sister to a AO cat)
shortie bravo 1 drive
12" notched transom
12" adjustable extension box
600hp
The drive height is currently set centered on the center sponson (the deepest point)

I already had a 30" stock Bravo 1 prop and it was running against the rev limiter. My dealer loaned me a stock 32" bravo and the boat ran 5mph faster (89mph @5100rpm). This calcs out to 15% slip. The boat felt and trimmed pretty neutral with the bravo prop, although some more testing would be needed to confirm that. :D There was some very slight paddle wheel with the prop, although it was nothing that was really scaring me. The 30" planed out suprisingly well with very, very little slip, but a lot of bow rise. The 32" was rather sluggish getting on plane and would slip when tipping over. There was even more bow rise with the 32 than the 30. Where on earth is all this bow rise coming from?

Ultimatly, what do I do to get that slip down? I'm thinking that I'm going to need a whole different type of propeller. I was looking at some outboard props, but found that the diameters were not large enough. Somebody also warned me that the blades might be too thin for my app. I'm currently looking at a Hydromotive Q4+ and a Hoss Hyperdrive Offshore.

Your thoughts and input sure would be appreciated.

Cord, What did Rod say about using a Cleaver as I suggested? Glad to hear you're on the water, looks like you're well on your way to that triple digit mark! Steve

Try a 1/2 to 1" drive spacer and see. What drive ratio do you have? Or try one of those hard to find Herring 5 blades 30".

Rod wants to try a standard length lower (2") and stick with the Bravos. With 15% slip the bravo prop isn't even in the ball park for what the boat needs. He doesn't know what the slip calcs out to. I think that he was picking up on something not being right but hadn't put the two together. Originally I was thinking cleaver, but now I'm not certain. It's really hard to find somebody with a 32" cleaver that they're willing to loan out. Hint, hint. :D

Cobra-I can still go down 1 1/2". It's a bit of a pain as access is poor, but doable. Proably not a 15 minute job (to the next unit of measure right Audio? lol).

Cleavers are as hard as hydromotive 4 blades to get on plane.

I've used the Hydromotives before. I'm not sure if it would plane out or not on this app. It would be worth trying though.