fastboatfella

Just wanted to say thank you to those who helped with my questions. I have not posted in a while because of the amount of work putting this boat together. We have run the boat three times now and just spent a enjoyable 4th of July.
The boat runs great! Very amazed by LaveyCraft and there hull design. Never would of thought this big boat would be as fast and nimble as it is. I made my 70 mph goal and then some with no supercharger at 6200ft in elevation. Runs 73 Gps with four people and lake gear. This was with a 26 pitch labed Bravo 1 at 5200 rpm. Heading back this weekend to try a 25 pitch Hydromotive PX-5.
When I get a chance I'll take some pictures and load them up for you.

Thanks again!

P.S.

Still learning to drive the 29 any tips would be greatly appreciated! Found 2 mph by dropping the starboard tab from 0 to 1 on the indicator.

bert4332

I found my 29 did not respond much in the way of bow drop or raise with the trip tabs. I set them neutral unless in snotty water. I would just play with the prop as you are doing and play with the trim on the drive. It will take you a good month of wheel time to get to know the boat and you'll see what it will respond to best. Good Luck and look forward to see the pics.

fastboatfella

That does not surprise me. I was talking with a fella that runs a 28 Eliminator speedster with twin Ilmors (710) at our high lake and he was saying that the thin air changes the way the hulls ventilate. Which can change characteristics of cats and stepped hulls. This fella has been around and used to campaign a Nortech at all the big poker runs. He has also been through the schools. Thought it was interesting conversation.

Bert you may find this interesting....started with a stock 26 pitch Bravo 1 boat ran good. Then I tried a 24 pitch lab Bravo 1 and the boat was a real hot rod! Ran 74 on the 5800 limiter. I don't know what the boat would have run if I had raised the limiter, but feared tearing up the xr drive with RPM (this was neutral tab). Slip was a little high also.

The last prop was the 26 lab that I stated ,with slight starboard tab. Looking forward to trying the 5 blade!

bert4332

I've never boated in high altitude, so yes that's pretty cool to learn something new with that regard. Are you running a stock 525? That five blade is gonna bite pretty good on getting out of the whole, I think you're fine with the XR drive, if you getting into bigger power with the 5 blade you need ease up on the stick out of the hole. I'm very interested in your top end on the 5 blade. My "guess" is it will be lower but your mid range acceleration should really kill it.

fastboatfella

Bert, we went up for the weekend and after talking with Bblades I decided to try a Hydromotive X four blade that I had. This prop was right were I expected at 5500 rpm but the boat slowed down to 69 and handled poorly. Never had a chance to bolt the five blade on and feel that this was a mistake. Next time, which will be in two weeks we will try it.
Motor is a 565 ci 735 hp at sea level makes 559 at elevation. We find that most boats pick up 11 to as much as 15 mph at Havasu.
The five blade is the only question left. Right now I am digging the 26 Bravo 1 lab is the best all around, but still will try the five.

Thanks for your interest!

bert4332

"26 Bravo 1 lab" That's the exact prop I wound up using. Definitely post on the way the five blade performs, I'm real interested. That's an amazing difference in the hp, you go from 565 to a 525 with the elevation. I knew it would change it, just didn't realize it was that much! Good Luck

GoodTrade 2750

Fastboatfella,
I'm enjoying reading the details as you dial in your boat since I'm in the process of getting to know my "new-to-me" 2750. Not the same boats but from what I know, the botton designs are similar and I would expect they respond similarly to propshaft height and general propeller types. Is your Bravo XR standard length? I don't know where the X dimensions are set from the factory but I'm anxious to do some coparisons of propeller shaft height.
Like Bert, I'm blown away with the power drop with altitude!

Good luck with the 5 blade trials and I look forward to hearing how it goes. Mine is set up with an Imco -2 lower and I am thinking I'd like to try a 5 blade prop to see if I can reduce the slip at lower to mid-range speeds.

I used to have a twin-step, twin engine go-fast with ITS and Sportmasters but a pretty high X dimension (slip percentages in the upper teens at lower speeds). I bought a pair of 5 blade Herings and they made a world of difference in the overall efficiency. Although your boat sounds as though it is pretty well hooked up!

Good luck with the testing and looking forward to hearing how it goes.

Thanks for sharing your results!
-Paul

fastboatfella

I will keep you posted! Yes power is typically a 24% loss! 735hp to 559hp wow! No one believes it till they try it! The boat will run over 80 at Havasu and need more prop.
Have a friend that just bought the 28 Nordic Heat that is on there web site. Real pretty boat with blues and silvers and has a merc 600 supercharged motor. Drove it at Desert Storm and ran 80 on gps. The boat will only run 69 up here!

The Lake is worth it though! Beautiful! Come on up our hospitality is second to none.

fastboatfella

Thanks Paul for being interested! The Drive is deep on the 29's compared with your 2750. I had thought about playing with the X dimension, but after talking with Chris at Lavey and other's that I respect including Eric at Teague who used to work for Lavey ( has a lot of seat time in the 29) decided against. The drive is standard length and deep helping to raise the bow. Prop slip is also good and everyone is advising that there is no gain by playing with the X dimension on the 29. From what I understand the 2750 likes a higher X.
Heading back to the lake the 25th and I will stick the 5 blade on and keep you posted!

Thanks fella's!

BUP

iTrader: (9)

Mercruiser has a service bulletin years ago about drive gear ratio changes and prop changes for high altitude running. If I find it I will post the number of the service bulletin so hopefully you can pull it up some how. Just saying as it might help you with some info.