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stumbledog
05-17-2006, 06:18 AM
Just pulled my prop to be re-worked. Should I have a cup on the lead edge of my blades?

stumbledog
05-17-2006, 09:26 AM
Anyone have some input?

stumbledog
05-17-2006, 09:34 AM
Just pulled my prop to be re-worked. Should I have a cup on the lead edge of my blades?

http://www.rundquist.com/how_prop_works.htm

Sorry, it is the trailing edge I guess.

Workin' 4 Toys
05-17-2006, 10:37 AM
Interesting link on prop finishing as well.

TMCNo1
05-17-2006, 11:20 AM
It should be cupped to OEM specifications, if the prop came with a cup, depending which manufacturers prop you have. A quality prop repairer should know or send it back to the manufacturer for them to repair to their original specs.

bigmac
05-17-2006, 11:55 AM
I don't know...I don't think there's anything magic about a particular prop relative to a specific boat. In many cases, the props are selected off the shelf by the boat maker, and they take the one that works the best rather than custom-specing a prop. The result is the reason so many of us are buying aftermarket props, finding props that work better than the ones MasterCraft selected for the boat.

My prop guy is into custom tweaking. He will spray a prop with mechanic's paint and put it back on the boat, run it for awhile, then see where the paint wears. That indicates an area of the prop that's not hitting the water and contributing to cavitation. In some cases, you can actually see cavitation burn on the prop, and in extreme cases, you can see cavitation burn on the rudder and hull behind the prop. Just because a prop doesn't cavitate on the manufacturer's bench doesn't mean it won't cavitate on the boat it's installed on. Using the mechanic's paint pattern, he reshapes the leading or trailing edge while leaving the geometry alone.

stumbledog
05-17-2006, 12:02 PM
I have an OJ prop. Does anyone have a good link to their web site. For some reason I can not get to it....

TMCNo1
05-17-2006, 12:13 PM
I have an OJ prop. Does anyone have a good link to their web site. For some reason I can not get to it....


www.ojprops.com, or 1-800-359-9730