More cupping to a Rapture?

[Steve VMS]

Good afternoon all!!

I recently purchased a michigan Rapture propeller for my Johnson 50 hp 2-stroke. I wanted to make the switch to steel for the durability and handling more than anything, but it seems that this prop slips like crazy coming out of the hole (no vent holes in prop), and slips in cornering similar to the stock aluminum I used to run a couple of years ago.

Numbers: Solas Alcup: 12x17 @5500 RPM GPS speed 33.8mph
Rapture: 11-3/4 x 15 @5600 RPM GPS speed 32.5mph
Max RPM = 5500
Motor is in 3rd hole up off transom

Before going to the Rapture, I ran a solas alcup 3, which performed really well in the 3rd bolt hole. As I compared the rapture to the solas visually, it seems the prop fins of the rapture flatten out a bit in the center of the fin, where the solas has a nice smooth curve from leading edge to trail edge. both props are said to be cupped, but the solas aluminum outperforms a rapture steel, and seems to have better cup...I am not too worried about speed, but the biting capabilities of the steel prop in cornering the boat.
Would reworking the fins to have even more cup on the rapture help, or am I better off just selling the rapture and continue to buy the aluminum every time I ding a prop? I would like to keep the motor in the third hole up.

Thanks much!!

Steve

[Jeff S]

Check this "message" previously
Nov 17th on previous page of Boat & Motor board




same issues you are having. Wrong pitch, cupe etc

Can you help me choose a better prop? Miami Vice Nov-17-03 03:26 AM
by Miami Vice 5 201

[Tom PP]

It sounds like the Solas has a lot more progression built in to it and that is why it bits better. I remember seeing a picture of one of those a couple years ago and there is noticeable difference in how they look to other props. I have also heard nothing but praise from people who run Solas props. You are limited on what kind of stainless props you can get with a low hp motor. Your other option is to send your prop to a high perf prop shop and gamble they could get it to bit better by putting more tip cupping in and or pulling in the lead edge by the root to give you some more progression on the stainless.