repowering question

[Bushwacker]

Originally Posted by junior11

. . . I can't really keep the boat on plane in anything less than 22 kts. I went to a 4 blade prop, changed pitch, all that stuff. . .

That's a pretty high min planing speed, so I'd guess you're fairly stern heavy, although I would think a 23 would be less sensitive than a 20 to the CG shift caused by a bracket. I'm surprised you can't plane slower with a 4B prop unless it's a bow-lifting prop like a bass boat would use. Are you using trim tabs, because that also helps?

Would be interesting to know what the min planing speed is on a 23 CC with a light 2-stroke motor on the transom for comparison. I think Potter put more deadrise in the outer panel of the 23 compared to the old Moesly 21, which would plane at about 12 mph with a V-8 Mercruiser; that relatively flat outer panel provides a lot of lift, so increasing deadrise on it would tend to reduce lift and increase min planing speed.

My boat is also stern heavy with a 30" bracket and 427 lb motor. I also had a 22 kt min planing speed until I went to a stern lifting PowerTech 4B prop, which made a huge difference, allowing me to hang on plane at 12-13 mph, even with a very heavy load. That's what I could plane at with a 300 lb motor on the transom and not quite as much load. I've had trim tabs on the boat almost the whole time I've had it and they also help you plane at lower speeds. A Doelfin or equivalent will also give you some additional stern lift to reduce planing speed, but it adds drag and appears to reduce my fuel mileage by about 0.2 mpg, although that's not a bad trade when the seas get really rough!