Prop upgrade from 15.5 x 18p to 16x16p?

[jkaczman]

Question for you guys out there. I have a Bayliner 24" hardtop 2452 (~4500lbs) with a repowered 5.7L Merc 260, Alpha One Gen 2 outdrive. Currently using a 15.5 x 18p 3 blade prop. Boat Feels great, max speed is 38mph @ 4300 RPM. The recommended prop when talking to some people appears to be 16x16 on a 3 blade from what I'm reading. I ordered one because it was only $150 new, seem like a decent prop upgrade or stick with what I got?

 

[Bondo]

Ayuh,..... That should put the Rpms at Wot right 'bout 4800, where SBCs are Happiest,.....

 

[Sea Rider]

Just for the record, post wot rpm gained as usually loaded, will be interesting to know if engine has increased its wot rpm range + 400 or way more revs from current 4300 wot revs to whatever is now revving with 2 less pitch size.

Happy Boating

 

[QBhoy]

Wot rpms sound very low. I’d bet that wasn’t the prop it came with. Would likely be a more standard type like a 17” black max.
Loads of guys I know have great results with the 16x16 and 5.7....but usually on bigger cruisers like a bayliner 2855 for example.
I’ve been on my friends with this set up and it’s incredible the difference in hole shot. He carries a lot of gear on his boat and it always gets up without effort. It has lost top speed over the old standard prop. But doesn’t bother him. It’s also slightly higher revving at cruise speed than the old prop. I can’t be sure but I think the old prop was a 17” black max on the alpha he has. It’s a huge thing and only just clears the cav plate. Loads of people with similar boats have followed suit under the advice of the local Merc dealer. He sells a load of them every year. But as mentioned I haven’t heard of anyone trying it on a boat slightly lighter and similar to yours. If you run really heavily loaded. It might just be ideal !