3 blade to 4 blade..

[truckermatt]

i have a 4.3L mercrusier motor... with a 3 blade 14.25/21P prop...
It runs at 4700rpm and 44 mph (GPS)

When i have the boat full of people and skiing/tubing, it take a little while to get on plane, I was wondering if going to a 4 blade alum like this would help.
(http://boatpropellers.iboats.com/Me.../9582/?**********=487314686&*******=057009421)

i am already at the upper end of the rpm range, so i dont want to lower pitch, and i read that a 3 to 4 blade switch in same pitch will only drop about 50-100 rpms...

I am not looking for top speed when using this prop, It would only be use when skiing or tubing... other wise my 3 blade prop would be on for crusing

Thanks

 

[hwsiii]

Re: 3 blade to 4 blade..

Matt, usually hanging from a 3 blade aluminum propto a 4 blade Solas Amita will hange the RPM by 250 to 300 RPM in the same pith prop. What make and model of prop do you have on it now.


H

 

[sho3boater]

Re: 3 blade to 4 blade..

A 4 blade will grab harder, but that can lower rpm more and reduce power at same pitch. People I know like to drop pitch with a 4 blade and they really holeshot well for towing, then toss the 3 blade higher pitch on for speed.

A 4 blade would be right, it sounds like, at the pitch you have but unless your prop slips on holeshot it will not come up harder like a lower pitch will. You need to know if you are at a loss of power or prop bite. If power you need less pitch, if the prop is slipping the extra blade will help.

 

[truckermatt]

Re: 3 blade to 4 blade..

Matt, usually hanging from a 3 blade aluminum propto a 4 blade Solas Amita will hange the RPM by 250 to 300 RPM in the same pith prop. What make and model of prop do you have on it now.


H

i have a quicksilver 3 blade alum... 14.25" and 21 Pitch

 

[truckermatt]

Re: 3 blade to 4 blade..

A 4 blade will grab harder, but that can lower rpm more and reduce power at same pitch. People I know like to drop pitch with a 4 blade and they really holeshot well for towing, then toss the 3 blade higher pitch on for speed.

A 4 blade would be right, it sounds like, at the pitch you have but unless your prop slips on holeshot it will not come up harder like a lower pitch will. You need to know if you are at a loss of power or prop bite. If power you need less pitch, if the prop is slipping the extra blade will help.

if does feel like the prop is slipping when many people are in the boat....

mainly i want a better holeshot for watersports... and will use the 4 blade for everything else.