Propping a B3
 

I know I don't have a speed boat by any means but want some advice on proping a b3. Have a 23 foot boat, 496 mag 375hp, b3 1.81 drive with stock 26 props. Manufacturer states boat should run 60.8 mph with this setup. Have only been able to get 56.5 at wot of around 4300. Hull is clean and has all new plugs and filters. Boat weighs in at close to 4500. I believe a set of 24 props is the way to go. Hard to find a set to borrow and don't want to buy a set that aren't right. Sound like I'm going to be ok?

Pol83x,

24's will take you to 4700 and the engine will like this. Your acceleration will improve but top send will stay about the same. You may see a 1mph increase. This is the way to go in my opinion.
Manufacturers always test boats with low fuel and extreme minimum gear. So, the numbers tend to be best case scenarios.

Brett

Thank you for the reply. Any thoughts on the 4-3 setup or Signature 4x4's?

If you want low end grunt move to the 4x3 or 4x4's. I personally like the 3x3 sets because there is more adjustments and tweeks that can be done to them.
The 3x3 sets are typically the faster set up especially when slip % is low to begin with. Mercury created the 4x3 in the early 2000's as a fix for cavitation burn when mounting B3's to high HP applications. In a effort to decrease inventory costs and as a way push sales on the newer technology, the current 3x3 B3's will be discontinued.
I'm not happy with that decision.

Brett

Thanks I'm now on the hunt for a set of 3x3

Quick update. Picked up a set of 24p 3 blades that were just checked and polished for a steal, now just got to wait till spring. Only thing I can do with them now is make a big ol mixed drink.

Awesome. Let us know how they work.

Brett

My '04 Chap 260 SSi with 496 MAG/Bravo III 2.0:1, 26" 3 x 3 prop set ran a best of just shy of 54 MPH GPS. Most days it was a 50 - 52 MPH boat. I don't see your boat doing 60 MPH but 58 should be doable. Update us in the spring. BTW, from my own personal experience Chap hulls do not like the 4 x 3 prop sets at WOT. Cruise they are great but they lift the stern too much on the big end and feel skittish.

Mercury created the 4x3 in the early 2000's as a fix for cavitation burn when mounting B3's to high HP applications.

Brett[/QUOTE]

So this is why I'm cracking and blowing out pieces of rear props within 30 hrs?......
22,000 lbs 640hp @ 5200/ 690ftlbs @ 4100 2:1 drives 28 p....maybe a candidate for the 4x3??

Potentially, yes.
Can you post some photos or send to [email protected]

Brett