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Prop cupping

Posted: Tue Jun 09, 2020 9:26 am
by captjimjr
Can anyone elaborate on cupping for 16×16 3 blade props. I see the chart calls for cupped props but doesn't mention light, medium or heavy, is there a standard cupping for our marinette proppping

Re: Prop cupping

Posted: Tue Jun 09, 2020 10:26 am
by Tuggle
Contact Bblades, 920-295-4435, have used them for years on my hot rod boat. There's a little art and voodoo that goes into prop tuning, much like welding "anyone" can do it but few have the true talent.

Re: Prop cupping

Posted: Tue Jun 09, 2020 10:47 am
by Fastjeff
You're signing from my hymnal!

The one time gurus of Marinette, Sir John his-self (I'm a southerner now, y'all) was instrumental in the industry what cup is and how it's defined (while he worked for Michigan Wheel). Hard to 'splain in print, but an example might hep yew out:

My old 32 footer was running 16 x 16 3 blader on the Port side, with a 16 x 15 3 blader on the other'n That the 16 x 16 had a mild cup--barely visible--where the 16 x 15 had a heavy cup (pounded in by a guy in my presence). Both engines operated the SAME.

Jeff

Re: Prop cupping

Posted: Wed Jun 10, 2020 9:53 am
by captjimjr
I see, had a guy try talking me into a 4 blade 15 inch with pitch and cupping to match or excede my 16×16's. And the ones I could match up from acme which where he said he went is a 15.50×15 4 blade. Jeff does this sound like something that would work out.

Re: Prop cupping

Posted: Thu Jun 11, 2020 6:09 am
by Fastjeff
Sounds reasonable. A 3 blade 16 pitch is similar to a 4 blade 15 pitch (ODs being similar).

The bottom line is that our beloved Marinettes JUMP onto plane compared to plastic boats, so you can use far more prop on them than is customary (and get better gas mileage).

The eyes of my plastic boat buddy bulged when i planed my 32 footer of--easily--at only 1/2 throttle. His 28 foot Sea Ray (454) required all it had to make plane, and dropped off under 3,000 rpm. And when he saw mine hold plane a 2,000--and after making a tight, 360 degree turn--he was stunned!

Marinettes rule!

Jeff

Re: Prop cupping

Posted: Thu Jun 11, 2020 6:15 pm
by bcassedy
Amen, Jeff!!!