Propeller - 3 or 4 blade ?

[Monza]

Looking to upgrade my Suzuki 140hp alloy prop to a stainless prop for more speed and efficiency. Solas recommends a 4 blade prop upgrade but this is more expensive than 3 blade prop. Has anyone tried this change and got good results ???

[Streaker]

Monza
I recently fitted a 4 blade to my 140 Yammy. I get about 3knts per hour more flat out but the saving is the it goes faster through the range at a lower RPM. I am yet to do a accurate fuel comparision but at a glance the economy seems to have improved. Myself and others that have travelled in the boat seems to think that the boat gets through the water better, more bit and more push. the good thing about buying off Solas is if you don't like the prop you can change it for another.
well worth the extra money I think.
Wayne

[melbdan]

Hey Monza what have u got the suzuki on and what speed are u getting out of it i just brought one of these engines with a 3 blade stainless prop but wont have it in the water for anouther 3 months also is it goos on fuel thanks Dan.

[dnej]

Wayne, did you see the post by Touchy yesterday re paying for your prop.
David

[Monza]

Suzi 140hp 4 stroke with 19" alloy prop is pushing a Signature 600RF to 37mph. Every review I read says this motor should push the boat to low 40's. Revs are at lower end of recommended range so maybe prop pitch is an issue, or maybe my expectations are just too high.

[Mr__Bean]

Hello Monza,

I have just ordered a four blade Solas to go on a 225F Yamaha.

The reason I went for the four blade is as follows.

Before my annual holidays last year I dropped my 3 blade prop in for a minor repair, the dealer assured me it would be back in plenty of time for my holidays and all was well.

About a week before leaving I rang the dealer to see where my prop was, he fobbed me off a bit and said he would get back to me. Days went by and still no prop so I got a bit sweaty and give him some of my thoughts about his service.

He ended up loaning me a five blade prop for my holidays on the understanding that if I dinged it then it was mine to buy, I accepted his offer and took the boat on holidays.

Well you wouldn't believe it was the same boat, where it used to lose speed after hitting a big wave with the three blade prop, the five blade one would just push the boat straight through the wave without loosing momentum at all. I couldn't believe the difference.

My advice (for what it is worth), to change from 3 to 4 blades chasing a couple of mph is a costly exercise, if however you regularly have to punch through some rough water, and you find your are loosing boat speed due to prop slippage, then fitting the 4 blade will give better performance.

If however, your main use is on relatively calm waters, I don't think the benefit is cost effective.

Good luck.

- Bean

[Slates]

I've got two props pushing a 3.9 stacer with a 25hp on it.

The pitch and diameter differ so I guess it isn't a fair comparison, but the 4 blade revs better and give a higher top end.

Cheers, Slates