Prop/performance help
 

I purchased a 1993 Hallette 270S that had a 2009 496 mag ho professionally installed in it. It has a Bravo One drive 1:50 and a 4 blade 24 pitch Mercury prop. It's performance is concerning, while I realize it's only a 496 it has more horse power than the original 502 that people claim get 65 to 70 MPH out of in this boat model. I have to trim tab down to get it on plane, mid range acceleration is fair and at WOT it turns 4600 rpm at 54 MPH ( it has a Loversi GPS speedo and I checked it with a hand held Garman). Anyone have any thoughts how I can wake this boat up?

Something is definitely wrong since you can only pull 4600 and your slip % is at 20%.

Call us if you like and we can go through some set up questions.

Brett

I just purchased a 2005 Donzi 38 ZR with staggered 525's , I am being told that 15 " maximus props 30 pitch are probably the best props for this boat, any thoughts ? The previous owner was running some herrings but it took forever getting on plane. but when it did it turned at 5100 rpm and he got 90 out of it. He did not use the boat for poker runs. I will be , and I like the idea of 90MPH on stock merc power but I don't want everyone to take off and be a half mile ahead once I get on plane, I might never real em in ! ? Does anyone know what prop setup is best for this boat if you want to get out of the water fairly quick and still get great top end turn ?

After posting for prop assistance, I took advantage of Brett's offer to assist. Brett had me verify the top speed and RPM one more time, get the actual boat weight and have the engine checked out to ensure it's running properly. Once this was all accomplished, I sent Brett the prop and here is what he found and performed:

Hello Paul.

Ok, the propeller had been work prior. Some thinning and minor cup reduction had been performed. Before adjusting the geometry via our Lab process, we welded two flat spots on the leading edge to gain back the full blade are. My assumption is that those spots were poor repair jobs at one time. We then Labbed the propeller to a recipe appropriate to your application. This involved changing the pitch progression and cup height and location. (your cups were not matched prior). We also adjusted the rake angle by specific tip bends and matched the blade thicknesses via thinning the blades to a specific/custom thickness curve. We then balance and buff the prop to our satin race finish.

I certainly hope and expect performance improvements via our adjustments. I hope you will notice better trim reaction and over all boat attitude as well as some speed gains.

Let me know any other questions you have.

Brett


I have not had the chance to test out the work Brett and his team performed, but I can tell you that to this point my experience with Brett and BBlades has been second to none. I'll share my test ride experience with you soon.

Paul