Prop Question, diameter & pitch...
 

Hey Guys...

I have a few questions regarding propellers. My setup is a '97 Donzi 22 Classic with a 385hp/454MAG that I bolted a Blackhawk up to (stock Bravo X-dim). So essentially its acting like a shorty Bravo 3. I am currently spinning a set of 27P BlackHawk props and I know the front one has a 16"+ diameter. Not too sure about the RPM @ WOT, as I don't trust my tach. I am going to calibrate my tach this weekend, but say somewhere in the order of 4400 RPM. I am thinking about testing a set of Bravo 3 props just to see if I can gain some rpm and speed. I wanted to try the 15" x 28P cupped Bravo 3 propset.

I wanrt to know, what does adding cup do besides reduce propslip %, and what will the small diameter do? Just want to comfirm with the smart ones, that I am on the right page...


Woodsy

props adding cup/blackhawk
 

most of the volvo dual props have cupping on the smaller prop,most all of the bravo 3 props do not have cupping,and to you question adding cup will decrease the rpm around 150 to 250 depending on how much ,also it will increase the forward travel if you can turn the motor at the top of the rated rpm range.Long story short you may want to have the props thinned out to obtain higher rpms and then add cup to the smaller prop.