4 Bladed Prop Expectations

[SNye45]

It's going to be a long time until I can get on the water to test this change- It snowed this morning.

But I am eager to hear about the changes to my boats performance

My engine is a 2007 Suzuki DF115, Boat is a 20ft Aluminum.

Until now I have been using a 3 bladed prop with a 19" pitch. My next door neighbor who had the same engine recently upgraded to a Suzuki 150 and offered me his 4 bladed prop (same pitch)for a good deal, which I accepted.

My current results with the 3 bladed prop are: Top speed = 36mph WOT @ 5800rpm
Best Cruise = 25mph @ 4000rpm.

Can anyone please help me with some numbers than I can expect from the 4 bladed prop.

Thank you

 

[aussiejake]

Re: 4 Bladed Prop Expectations

Expect to lose around 400rpm at WOT with a 4 blade the same pitch as your 3 blade.
I lost 500rpm from a Mirageplus 17p to a Stiletto Bay pro III 17p.

 

[aussiejake]

Re: 4 Bladed Prop Expectations

Also with a 4 blade make sure your engine height is correct. See thread below.

http://www.veradoclub.com/smf/index.php?topic=137.0

 

[tpenfield]

Re: 4 Bladed Prop Expectations

It's going to be a long time until I can get on the water to test this change- It snowed this morning.

But I am eager to hear about the changes to my boats performance

My engine is a 2007 Suzuki DF115, Boat is a 20ft Aluminum.

Until now I have been using a 3 bladed prop with a 19" pitch. My next door neighbor who had the same engine recently upgraded to a Suzuki 150 and offered me his 4 bladed prop (same pitch)for a good deal, which I accepted.

My current results with the 3 bladed prop are: Top speed = 36mph WOT @ 5800rpm
Best Cruise = 25mph @ 4000rpm.

Can anyone please help me with some numbers than I can expect from the 4 bladed prop.

Thank you

My guess is going to be 33 mph @ 5300 rpm, cruise at 22 mph 3700 rpm, better cruise lower top end

Hopefully you will get a chance to try it out soon.

 

[steelespike]

Re: 4 Bladed Prop Expectations

Your slip is near the high end of normal 10%.Is your speed by gps?
If the 4 blade can lower slip to 6% and you end up at
5500 my calculations indicate 35, speed could be a wash.
Can't be too specific but usually the 4 blade will stay on plane easier at reduced throttle,have better hole shot
and should handle better around the dock.