Thread: Prop Question
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Old 10-21-2019, 09:45 AM   #3
rslifkin
Guru
 
City: Rochester, NY
Country: USA
Vessel Name: Hour Glass
Vessel Model: Chris Craft Catalina 381
Join Date: Aug 2019
Posts: 797
I know low speed slip will always be higher. But would going to a bit more blade area (either more diameter or a 4 blade) with less pitch possibly be more efficient at the lower speeds? In theory it should show a bit less slip. And speed, slip, etc. at WOT is pretty irrelevant for my use as my typical cruise is a solid 9 kts below WOT speed.

Speed-wise, if I'm doing better than about 18 - 19 kts, it's for the once or twice a season brief WOT check. My typical cruise is in the 17 - 18 range. Cruising faster than 18 kts or so is just asking for too much continuous output from the 454s IMO. As far as speed at WOT, Chris Craft lists 28 kts at 4000 RPM as built. I've personally seen a bit over 27 kts from it.

Maybe I'm best off saving the $$$ and just throwing the 22x25s I've already got on there? Assuming WOT slip stays constant and I gain 200 RPM at WOT, the boat should actually be a hair faster with those on in addition to being kinder to the engines.
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