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Not sure how much help I will get but I have a 1973 25 Bertram flybridge with twin straight 6 165 mercrusiers. I currently have 4blade aluminum props 15x16 with counter rotation. Wot is port 3950 and starboard 4110 @28knots. So I’m looking to put stainless wheels on but was looking for anyone who has this setup for real numbers. Thanks for any help I can get.

Have you made sure both engines are performing the same and throttle cables on both are opening 100%?

You could also have the hubs checked for slipping on current props. Those engines don't put out enough torque and hp to warrant spending money on stainless props(i.e. helping to keep blade shape under load)

Don't forget drive hub slippage also.

I’m just looking for 1-2knots at cruise and maybe alittle fuel economy. You don’t think I will see any improvements? I always thought these motors had a lot of tourque.

I have a 72 with 165’s I cruise at 28 @ 3000rpm
If memory serves which it often doesn’t I have 3 blade aluminum 15 x 21

If I go back to 3 blades it has to stainless, they don’t make a counter rotation 3blade.
So you run 28mph at 3000rpms?

Also is the bottom clean?

Boat was just put in so yeah bottom is clean. I’m lookinh to get stainless wheels just would like some information from someone who has them.