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Hi all, I just got a new to me 31 Bahia Mar. Engines are twin Perkins T6-354s with Hurth 2.0:1 transmissions and 1 38" shafts. Current props are 18x22.5 with .060 cup. I am getting my max rpms (2800) with a top speed of 20-21kts. Cruise is 2500-2600rpm at about 15-17kts. Trying to find out if I can get a better cruise with a different pair of props. Bigger Diameter? 3 or 4 blades? pitch and cup?. Love the boat and it suits my needs. I know she'll never be a rocket ship but a tad more would be nice. Thanks

Those engines are under 200 HP each. I think you're going as fast as you're going to.....

Everybody wants a TAD More Speed...

Two points from experience.

Remember playing with props can get expensive quickly.
That is unless you have access to free trial props with hauls for next to nothing or don't mind changing them underwater. I say that as sometimes the calculations can vary from the performance... can be from boat weight, boat configuration, trim, motors a little tired, prop style, brand, bottom condition etc.

2nd and most important...if you you do achieve that Tad More Speed, make certain you can still achieve rated WOT RPM. If not your extra speed will have you overhauling motors sooner then later.


Last thing...whatever you hear and you'll hear alot when you start asking, run your idea past a Good Prop Shop instead of just telling them what you want.


That said,
Are you running 3 or 4 blade props now?

I am currently running 3 blade bronze 18x22.5. Engines run up to 2800. I have been trying to find what the max rpm is for these engines but can't seem to. 2800 may very well be the max rpm, I just want to make sure.

Remember 4 blade props will drop the top end but up the cruise slightly.

But with those engines, as Mike said, you are about there on speed.