Acme props, 24 x 20 cupped for 4788 w/370s-gctid811852

[Wort123]

Does anyone have comments about Acme props? They are recommending 24 x 20 cupped props as an alternative to 24 x 22 without cups. I'm told they will lift the stern a bit and provide the same speed at slightly lower RPM. The supplier will repitch them as necessary when we can do a proper WOT test as the weather gets (yech) hot and humid.

[smitty477]

"Does anyone have comments about Acme props? They are recommending 24 x 20 cupped props as an alternative to 24 x 22 without cups. I'm told they will lift the stern a bit and provide the same speed at slightly lower RPM. The supplier will repitch them as necessary when we can do a proper WOT test as the weather gets (yech) hot and humid."

I know nothing about Acme props either good or bad.

Cupping is not an 'all or nothing' deal there are degrees of cup in a prop so without great details on that cupping your dealings with a prop shop will be limited.

Never had measurable cupping on the larger props as it reduces slip angle and can be hard to work around on larger slower boats - or so I have been told by the experts. Please know I do not pretend to be an expert on cupping and the results on these larger slower boats like the 4788 just what I know from props shops that specialize in the use and from past owners and my own experiences.

Perhaps another 45 or 47 owner has firsthand experiences with cupped props and the details that go along with it.

I do know about cupping as it relates to higher speeds and a couple of my past 'dinghies'....

Here are a couple of 'partly' cupped props on my last higher speed RIB....

[Wort123]

Thanks, Ron. I want to order them on Monday if I can get good feedback. Never considered cupping so it's a new topic.

[smitty477]

If just one owner on the BOC has the same props (Acme) and also has some performance data you can compare notes and baselines.