Fastlane_40

I have just repowered a new boat. I've worked our the kinks on the motors, and now I'm ready to dial in the props.

I have a 40' Fastlane with twin 540's dyno'd at 550HP. It weighs about 12,00lbs dry and I'm running Bravo I drives with Bravo One counter rotating 4 blade 15x24 props.

I've got to take my time getting the boat on plane or I just blow the props out of the water. Once I'm on plane its very responsive. The motors seem to still have a lot left when I run up against the ignition rev limiter at 5100PRM. Top speed is just under 67MPH at 5000 RPM.

I'm less concerned about top speed as I am about finding the sweet spot for the motors. Additionally, I wouldn't mind increasing the range of the boat. I'd like to start taking longer trips without having to fill the boat with fuel bladders.

I've read different posts, and I'm not sure if I should stay with the 4 blade and just play with the pitch, jump up to a 5/6, drop back to a 3, or a different. Any help would be greatly appreciated.

Thanks,

Dave

Somethin' Sexy

I am not familar with a Fastlane. A lot of variables to consider. Step or no step, pad or straight v all the way, fresh or saltwater. I would definitely not recommend 5 or 6 blades on bravo one drives with that heavy of a boat or you will be fixing drives. I would think you need to bump your rev limiters a bit. What is the recommended redline. Based on what you posted 540/550 hp I would think the redline should be around 5500.

bbladesprops

There are things to conceder.
One option is to just go up in pitch on 4 blades, since you're on the limiter, and the cruise/fuel economy will improve.
I do disagree the 5 blades are a bad idea. 5 blade props are easier on drives from a harmonics standpoint since they have shorter duration between load and unload pulses. Yes, if you are constantly hard on the throttles and fly the boat often, the 5 blade props can be harder on the drive since they hook up better.

We have 3 variety's of 5 blades to test with without having buy anything.
Let us know if this interests you.

Brett

Fastlane_40

It's a straight V Hull, currently fresh water. The boat was made in Australia and they only made 60 of them through 1991, I have hull #56. From what information I could find it seems like most are topping out around 60. Here's a link to an old youtube promo.

http://www.youtube.com/watch?v=t9bV7UjmTEo

Brett, I'm pretty easy on the boat. Can you send me info on the 5 blades?

bbladesprops

You're better off to call us and we can discuss the options.
We have Maximus, OXP's and P5X props to test for $45 per prop for a 15 day test period.
The discussion will determine the pitch and diameter options.

Thanks and let us know what you decide to do.

Brett