JS232

On a single engine application,

I know that a four blades prop is less subject to blowout...

What other benefits are gained using 4 blades?

For example, will the boat fly more level?

throttleup

You should have better hole shot, cruise speed may improve and handling will improve, typically less blowout .

Julie

JS232

Thanks Julie,

Would the boat fly more level in the rough ?

throttleup

Many factors effect the way a boat will "fly" . The prop is one of them. Drive trim and balance of the boat will also effect the way a boat "flys". Typically in rough water you will want the CG forward of where it is for top speed. This keeps the bow down and allows the bow to cut through the water and do what it's designed to do.

The prop, especially on a single engine boat, can influence the overall handling of the boat more than just about anything else you can do to the boat.

Matt

Boatshopping

Julie,

What is the rule of thumb when going from a three blade prop to a four blade prop as far as pitch is concerned? How much more cruising speed would four blade prop give (on avg.) in a twin engine application?

Thanks,
John

Boatshopping

Also any recommendations, currently running counter rotating 26p chopper props on a 24' Superboat with twin Merc 200 outboards. Thinking of either trying 28p choppers or a pair of four blade props.

Thanks again,
John

drypipetiger

A negative would be that it's harder on the drive.

bbladesprops

There are so many variables when it comes to choosing 3 or 4 blade props.

Yes, you can agree with the statements you see here on the majority basis. One other thing that should be noted is that on boats requiring mega bow carrying help, 4 blade props can actually hurt the top end performance, and handling due to there extra stern lifting characteristics. Also blow out upon acceleration and cornering can be a problem.

Boatshopping, plan on a 1" reduction in pitch when choosing a 4 blade replacement for your 3 blade.

Boatshopping

Thanks for the reply Brett!

From what I have read I don't think the Superboats need any stern lift although mine is fairly heavy with twin outboards on it. Do you have any recommendations for other props that I should try?

John

bbladesprops

Outboards, chopper props and Superboats have always been a popular combination. I'd like to suggest the Tempest Plus propellers but Mercury only offers them to 23 pitch in counter rotators. We could try the 25 Rev 4 in the 4blade and some Mirage Plus props in the 3 blade. These props will help the mid range you are running but may not help top end.

What are your current speed and rpm numbers?