Need opinions on prop/gears
 

I'm kinda at a crossroads with tuning in my boat...

28 Nordic heat with estimated 750-800 hp

Part of my build was to put a shorty lower unit on it and I found a great deal on a sportmaster lower on here, purchased it, and put it on..now here's the kicker..it was a 1.36 ratio as opposed to my 1.50 I had prior

My thoughts were that with the extra horsepower I might be able to get away without a prop change with the gear change which is slightly true...here's my findings...

26 pitch bravo....5000-5100 rpm trimmed to the moon 81 mph chine walked BAADDD
28 pitch bravo(was on the boat prior to build)...4800-4900 also trimmed to the moon 79-80 bouncing right on 80
Labbed 30 pitch bravo....45-4600 trim didn't matter too much 72-73 mph and felt like I was dragging an elephant obviously too much prop

I'd like to see RPM's in the 56-5700 range WOT as the motor says that will be peak HP with my current cam which is fine because it makes me a little uneasy twisting a blower motor much higher than that....so...options/opinions

1. Swap lower gears over the winter back to 1.50 and hope that the 3 current props I have will put me in the ballpark
2. Find/buy a 24 pitch bravo and hope it brings my rpm's up where I want them and have it labbed to tweak it in
3. Have the 26 labbed and see where that puts me

My concern is the amount of chine walk I saw on the 26...the 26 and 28 are both box stock unlabbed props and there was a night and day difference between the two as far as handling goes...so I'm wondering if the smaller pitch is causing me some issues or if it's because I have to trim the thing to the moon to get the heavy nose up with such a big single engine boat

My research has found that the hydro p-5x is the prop of choice for other Nordic heat guys however those reports were on stepped hull heats and mine is the non stepped pad version of the hull so I don't want to drop that kind of coin on a prop just to try it especially until I get a better idea on what pitch I would need....also hydromotive props are getting harder and harder to get due to some kind of issues at hydromotive....next step would be either herring or maximus but again until I get the motor in the RPM range I'm looking for I really don't want to make guesses on what I would need pitch wise so I think taking the variable of switching to a 5 blade off the table right now I'll just stick with bravo props...

What's everyone's thoughts/opinions??

Thanks!!

I would try a 25 Mirage or Mirage + to get the bow up with less trim and a little less stern lift. You can find one on Craigslist for around $100 quite inexpensive trial. Sell it if it doesn't work.

Really? I would have thought a 3 blade would hurt me more than help...may have to give it a shot...I def need more bow lift as the boat runs pretty "wet" at speed...if anything it will give me a cheap baseline of which way I need to go I suppose....thanks!

Any other opinions out there?

Anyone else??

How deep is the propshaft below the bottom? On a extension box?

No box and I will have to measure to get an exact measurement but I would guess with the shorty it's 5 inches or so below the bottom of the boat...the non stepped heats were pretty deep from the factory

I think you’d have too much slip with a 3 blade at just 5” below without a box. The Rev4 prop carried my boat very well, but I’ve heard they don’t lab very well. I never had good results with a bravo1. In my opinion they’re an old design that’s good for pushing a boat straight but not much lift. I think a 5 blade would creat too much stern lift at that depth. Prop testing gets old fast but it’s very hard to know what’s going to work without trying it.

It was hard to get a 100% accurate measurement as I can't drop the drive fully on the trailer...however I got it down close to level with the bottom and it was between 4 and 5 inches propshaft center below the bottom of the boat

I agree prop testing is already getting old that's why I was seeking a little advice on which direction I should head...Like I said before I do know that the stepped bottom guys almost exclusively use the hydro P-5X but I'm not sure about my non step pad bottom....I'd like to get my hands on a 24 bravo just to try it and see if my RPM's come up and how that relates to speed considering how high I have to trim it to get the speed I get...If the RPM's come up and I don't gain any speed then that will show me that I am just creating more slip with no gain correct? So then I would try something with more bite like a 5 blade maybe? I'm pretty new to this prop testing game so any advice would help...I called brett at bblades like 2 months ago and never got a call back...was thinking of trying him again today and picking his brain a little on which direction I should head as well