Trying to up-pitch a prop can change it's characteristics drastically. I had a stock Bravo 28 up-pitched and labbed by BBlades and it made my boat handle so bad it was unsafe. After putting $1000 into that prop and BBlades wanting about $350 more to try and fix it, I traded it for a labbed 30 which got me closer to where I needed to be and improved handling dramatically. Just saying be careful changing the shape of the blades as it could have drastic results.

I'm with Griff on this one. How high are you trimming? If you are able to gain speed while trimming, I don't see what the issue is. Now when you trim and all you gain is RPM, then yes, you are over propped and over trimmed. With that said, a Bravo 30 is not 30 pitch, it is actually only around 29, so using that in the prop slip calculator you are at 17% slip. Depending on your boat, that isn't bad for a 4 blade prop.

If you are set on a 29 this guy has one for sale, $525. It's a 30 that he had depitched to a 29. His name is Morgan, number is 540-470-0087.

A 30P is a 29P with a #4 cup, cupped at #6 it's a 30P, cupped at #8 it's a 31P, cupped at #10 it's a 32P, remember the more cup on the fan tail, the more stern lift you have, the more cup you have on the reverse edge the more thrust you have, you can cup to #2 but it better be nothing more than a little bass or the prop will blow out and not hold the water. Labbing has nothing to do with cupping or pitch.

What boat, and mods to the 525 EFI necessary to run a 30P, full head/cam at 650 HP, stock compression would be a 26P Bravo 1 or 24P Maximus depending on drive setup at 6200 RPM on a 1.5 gear, a base supercharged 525 EFI around 5 PSI with stock compression or a 540 CID with stock compression would be a 28P Bravo 1 or 26P Maximus, and a full head/cam supercharged 7.5/1 compression max boost 525 EFI or a 555 EFI at 9.8/1 compression would be a 30P Bravo 1 or 28P Maximus. Anything over 30P Bravo 1 or 28P Maximus is more prop than the XR lower gear can take whether on plane or not. If you want to run more the 30P switch to IMCO, they even make a XR/#6 conversion on the SCX4 to run a #6 prop on an XR driveline. Mine actually runs 16.71% on 30P Bravo 1 and 10.76% on 28P Maximus, same speed 97.8 MPH at 6200 RPM.

29P isn't going to do it, you should run about 5000 RPM with the trim all the way down and 500-600 RPM to trim with, a 28P cupped at #4 would be a 27P, my recommendation is 26P cupped at #6 for a 26P, this would give you max trim at about 5600 RPM, you can just trim back down to 5400 RPM.

There are other factors such as the -2" Imco lower. Dropping two pitch numbers would put me all over the rev limiter. The fact that I can turn 5,390 RPM now, when it's safe to run a lot of trim, tells me that I'm close. The rev limiter starts pulling power at 5,400 so I was 10 RPMs short of that and everyone tells me to run the 525 as close to 5,400 as I can. The problem is that I can't run that much trim on rough water. I need 300 more RPM, or one pitch lower. At least that's my understanding of it. Rhinda tool indicated that I was still at 100% power at 5,390 and 82.0 MPH. I have had this boat as high as 85.6 MPH in perfect conditions and I think bumping the rev limiter.

Here is the question I have, Can you run the boat 85 mph in rough water? I know with my 37 Active Thunder I couldn't. I would run 83 in 2-3's and 77 in 4's, and I had to really work it to keep that speed up, as the props were always out of the water. I tested at least 5 sets of props on that boat, the prop that gave me the max speed was not the one that gave me the most RPMs. I had 525s with the Whipple tune, in that boat and I saw the best speeds with a Hydromotive P5x 29 at 5150 rpms. IMO, you are perfectly propped right now. With 525s, what is the HP difference between 5200 vs 5490? maybe 10 to 15 hp, so at best .5 mph. The way I also look at this, as you are trimming up and gaining speed, you are lifting the bow more. Keeping the boat flat with with more RPMs isn't going to gain a thing, and now you won't be able to trim up when the conditions allow it.

Sort of, when I dropped 2 inches I add a blade going from from 4-blade to 5-blade, better hole shots, same top end and same rpm. I don't recommend shorties or drive spacers, just a blade for more stern lift. Your bump up on rpms maybe to 5600 rpms, that's all the stock connector rods will take, full head/cam and all the toys will go to 6200 RPM. Do you want the drive to do the work with more pitch for more speed or do you want the engine to do the work with more rpms and the same pitch. The information says you're porpoising on the trim set right now, with your rougher water numbers, in light chop it should go faster not slower, the setup should be for light chop and not calm water because you probably won't have enough calm water for it. Drive down, hit 5000 rpm, then trim up the rest to the rev limiter. Don't waste your time with Hydromotive, I've tested all of their stuff including the P5x, too much stern lift. If you want a 5-blade, go with Maximus. Gaining rpms are easy, I can pick you up 200 rpms+ on a labbed prop and 300 rpms+ on an unlabbed prop, with Hydroconic cutting, that's easy, and no waxing the props with carnauba wax to gain rpms, it will go slower not faster, Windex and polymer wax only to clean and prep, that's it. Sometimes you lift the bow more with more trim but that will depend on the x-dimension of the prop to the hull. Keep the boat flat is the point, when pitching the boat, pitch it flat to 5000 rpm at full throttle, then trim it to 5400 rpm, 4-blades post-trim, 5-blades pre-trim every 500 rpms.

The problem is that I often boat on the Great Lakes and cannot trim that high safely so my top speed runs are probably only turning 5,000-5,100 RPM. Trimming does lift the bow but it also lets the prop start to surface with the high X that I'm running.



First off, the shorty is a proven performance mod on the Donzi 22 Classic. Most of us run them. I never said that my boat porpoises; It does not but any 22' boat will get squirrely when it's trimmed to the moon. Of course it goes faster on light chop and it eats up 1-2s but I can't trim to get my rpms up where I want in honest 1-2s. I'm intrigued by the new Max 5 by Mercury and the claims they make but the prop costs $2,500 and I can't find anyone with experience running one. Right now I'm still leaning toward trying to find a 29p Bravo 1 or a 28 repitched to 29.