Solas Rubbex 4 blades vs 3 blades

[cloumar]

Now that I have made decision to stay with aluminum prop, here is where I need a bit of help. With the original Black Max prop 13.25 X 17P that came with the engine and on which I broke a blade my 115-HP Merc 4 strokes 2007 was making around 6100-rpm and near 40-mph and this with the anti vent plate of the engine level with the bottom of the boat.

With a Rubbex from Solas 4 blades - 13. 1/8 X 17P with regular load of 2 peoples and fishing gear it goes around 5800-rpm and 38 to 39-mph.

If I put on a Rubbex Solas 3 blades - 13.25 X 17P - is my motor will rev around the same as it was with the BlackMax or more or less ?

MC

 

[Oldskool]

Re: Solas Rubbex 4 blades vs 3 blades

You will likely pick up another 200 - 300 RPM with the 3 blade. General rule of thumb is that you increase 200 RPM with every 1 inch drop in pitch. You typically loose that much or a bit more when going to a 4 blade of the same pitch. A 4 blade will also typically drop a few mph, but will give you a better hole shot and allow you to stay on plane at a lower rpm.

 

[cloumar]

Re: Solas Rubbex 4 blades vs 3 blades

You will likely pick up another 200 - 300 RPM with the 3 blade. General rule of thumb is that you increase 200 RPM with every 1 inch drop in pitch. You typically loose that much or a bit more when going to a 4 blade of the same pitch. A 4 blade will also typically drop a few mph, but will give you a better hole shot and allow you to stay on plane at a lower rpm.

Thanks Oldskool,

I know the benefit of a 4 blades, where I am more concern is if the 3 blades Solas will give the same output = RPM / mph as the Black Max was giving me. Two years ago I bought a Legacy prop from TurningPoint a 3 blades 13.25 X 17P and it took down my RPM from 6100 to 5700 and also drop my top end to 37-mph.

MC

 

[cloumar]

Re: Solas Rubbex 4 blades vs 3 blades

Anyone has an idea - if the 3 blades Solas is having the same output of the 3 blades Black Max ?

 

[Hydro Head]

Re: Solas Rubbex 4 blades vs 3 blades

I'm curious about your setup also. I have a boat with a Yamaha F115 that I believe is the same engine as yours with a different gear ratio. Yamaha 2.15:1, Merc 2.07:1

My boat runs almost the same speed with a 17P prop. I just purchased a Cabelas 13-1/4x17P Stainless Steel(Stiletto??) and will try it out. I was considering a 17P Solas HR 4 Blade Stainless Steel, but am now having second thoughts. I'm just not convinced I willl benefit that much. I'm on the hairy edge as far as a 17P is concerned, maybe a 16P might be better when it comes to a 4 blade.

One thing you should try however is raising your engine. With the 4 blade I am thinking you could raise it as much as 2 inches??? You'll get back some RPM, and hence a little more speed. Our engines hump is right around 5800RPM and being just past that will yield the most speed in my opinion.

Since I cruise in the 4100 to 4500 RPM range, that is what I am most interested in. As it drops to around 3800RPM I begin to lose plane. Does your 4 blade help this out?

 

[cloumar]

Re: Solas Rubbex 4 blades vs 3 blades

I'm curious about your setup also. I have a boat with a Yamaha F115 that I believe is the same engine as yours with a different gear ratio. Yamaha 2.15:1, Merc 2.07:1

My boat runs almost the same speed with a 17P prop. I just purchased a Cabelas 13-1/4x17P Stainless Steel(Stiletto??) and will try it out. I was considering a 17P Solas HR 4 Blade Stainless Steel, but am now having second thoughts. I'm just not convinced I willl benefit that much. I'm on the hairy edge as far as a 17P is concerned, maybe a 16P might be better when it comes to a 4 blade.

One thing you should try however is raising your engine. With the 4 blade I am thinking you could raise it as much as 2 inches??? You'll get back some RPM, and hence a little more speed. Our engines hump is right around 5800RPM and being just past that will yield the most speed in my opinion.

Since I cruise in the 4100 to 4500 RPM range, that is what I am most interested in. As it drops to around 3800RPM I begin to lose plane. Does your 4 blade help this out?

Hi Hydro Head, well first our motors are not the same my Merc is one of the new generation base design from the Verado and its max RPM range is 6400 - which I believe it is 6000 for yours.
As for the 4 blades yes it does help to keep it in plane at slower RPM/speed, hole shot also was improved but no more than that, I went from a 3 blades 17P Black Max to a 4 blades 17P Solas and lost around 300-rpm.

As for raising my engine I did that 2 years ago - it was at about 1 3/4'' above bottom and I got able to get the engine reving to 6300 and catch 45-mph average with the 4 blades Solas, but even with the 4 blades I had to be careful when triming at this engine height it was easy to spin free catching air, when I was alone OK but with 2 peoples and let say front livewell fill with water - on the take off I had to trim it very slowly otherwise it was catching air. Now I set it back to about level with the bottom of the boat and I don't have any issue with catching air and I could trim it as I want.

MC

 

[Hydro Head]

Re: Solas Rubbex 4 blades vs 3 blades

Hi Hydro Head, well first our motors are not the same my Merc is one of the new generation base design from the Verado and its max RPM range is 6400 - which I believe it is 6000 for yours.
MC

Wasn't sure what year they changed over. I have a friend with the Merc/Yamaha powerhead. You are correct, tops for mine is 6000. 6400 is getting it done. And 45mph? I'm impressed. I have not tried changing engine height yet(just purchased the boat), but thanks for the feedback.