max prop and universal m25 question.

[john2]

I found a brand new 2 blade 14 inch maxprop classic. This was a non finish prop (no taper and no key) in a second hands store.
Changed the prop hub to fit on the shaft , but here it comes..... What pitch does need? Ihave the list with code numbers for settings but there is no conversion from 3 to 2 blades.
Has anybody placed a similair prop with the universal engine setup? For a reference for the pitch settings?
THe old prop was the original 3 blade 15x9 .
The boat is a cat 310, settings of an older/ other catalina's are also welcome. (c30 , 315 , 320 ect.)
thanks john

 

[dlochner]

Have you called PYI? There are several factors to consider, engine HP, gear ratio, engine's power curve, among others. The blade are of the Max prop is much smaller than the blade area of the 15x9 3 blade prop, that may become an issue.

 

[Tally Ho]

Agree with Dave…call Fred at PYI and the can tell you what pitch matches your engine and transmission.

They will need not only the engine specs but also the transmission ratio, and length & displacement of your boat.

The really good thing with MaxProp is that you can adjust the pitch. But that prop may not be the most efficient for you boat. You are losing a blade AND reducing the diameter… Might be a reasonable compromise to get better sailing performance (if you don’t motor that much).


Fred Hutchison
hutch@pyiinc.com


Greg

 

[john2]

Update. the max prop works great! under sail we gained almost 1 knot in speed. motoring we lost 0,2 kn. now 7,0
the boat speeds up some what slower but it gets there.
What a difference, the rattle in forward at idle is gone. the 2 blade maxprop has less flywheel force. (yes i need a new damper plate)
prop walk in reverse is almost gone.
For settings i used the old props blade angle as start. for 1 inch less diameter and 1 blade less each a setting postion higher.
john