bulletbob

Are you guys running 14.5 or 15 inch diameter props?

kiwiracer

i ran both 4 and 5 blade props on my race cat, 27ft with twin 300x.

14 x 30 4 bladed Merc Cleavers Labbed in the rough

14.5 x 31 5 bladed Herings in all other conditions

The 5 bladers were awesome and gave the boat the extra lift it needed in the calm

tzrider

iTrader: (-1)

What Ryan said....

mikesufka

This is very interesting and the first I've heard about running "5-blades" on outboards.

Could you comment more? i.e. What happens with top speed, comparing 3 blade Cleaver, 4 blade Cleaver, and 5 blade Herings? Assume same boat, motor, etc... Do you have to change engine height or set-up with these different props? Acceleration on bottom end? Mid-range? Weight carry ability?

If I swing 15 X 32 Merc Cleavers at 6200 RPM with my Spectre and 300 Promax combo, for speeds in the 95-97 mph range, what happens with a pair of "5-blades"? What pitch would you recommend?

Thank you.

Mike

Brad Zastrow

I guess I have been out of the outboard stuff too long. When I ran the four blade props I lost 5 mph. I would think running 5 blade props will allow a little higher engine height that would offset the stern lift problems I witnessed. The racers are using five blade props but I have yet to see them on a pleasure boat. Maybe that will change now. I am curious what the top speed differences are for three, four or five blade? I was just in a 120 mph 28 Skater a few weeks ago that my friend owns and he runs three blade Mercury lab 15 x 34.

Maritime_Eng

With my 30 motion with 250xs's I went From 94 mph with labbed 3 blade 15X32 to 98mph with labbed 4 blade 15X31. Also the midrange also is much better.

The difference in vibration from the 3 to 4 blades is night and day. The 4 blades are really smooth which has too be better on the lower units.

Also my old 30 motion with 300x's had 14.5X32 stock mercury 4 blades and it ran 105mph.

tzrider

iTrader: (-1)

With my 30 motion with 250xs's I went From 94 mph with labbed 3 blade 15X32 to 98mph with labbed 4 blade 15X31. Also the midrange also is much better

THOSE AREN'T ORDINARY 15x31 FOUR BLADES......

Maritime_Eng

LOL, Yep I know, you and Gary have some killer props. We are going testing sunday and hope to see over 100mph with stock 250xs's! Thanks again for the props!

tzrider

iTrader: (-1)

I have another set of " those" if someone needs them...

Allirunner

What props are these?