Solas s/s prop for Mercury 60 efi (4 stroke Non Big foot)

[RoccoST]

Hi,
I'm looking to buy a SOLAS stainless steel propeller and I have a few questions ...
The recommended engine wot for mercury 60 efi is 5500-6000, with solas amita 3-blade prop I have a 5700 rpm (11 1/8 x 13) but very poor cruising speed, with solas amita 3 blade 11 1/8 x 14 pitch I have a 5100 rpm and great cruising speed (but WOT is too low), and now I'm looking for a stainless steel prop that will provide a friction between those two, and which will raise the speed in relation to this prop 13" pitch with which I have a low speed (I'm talking about cruising speed).
I have been thinking about solas Saturn and New Saturn prop, but I'm a little rebel fact that new Saturn has a larger blade area, so I wonder what you think is the difference in surface or in rpm's between Saturn and New Saturn, or what would you recommend?
tnx

 

[RoccoST]

No one???

 

[steelespike]

Before investing in a new prop you should confirm your tach is accurate, and is speed by gps?
We need numbers to evaluate your results.
Are you picking an arbitrary cruise rpm or a particular speed? Regardless of the prop your best practical cruising speed
could be from just on plane to about 1000 rpm higher.
It's logical that identical props different pitches that the lower pitch prop will very likely produce less speed at the same rpm as the higher pitch prop.
Also the lower pitch will very likely require less throttle to produce the same rpm.
An accurate wot gps speed will help us get an idea how accurate the tach is.

 

[RoccoST]

Recommended wot is 5500-6000, and the speed is measured with GPS and RPM with SmartCraft...

 

[WIMUSKY]

Hey Rocco, I think what steele is getting at is we need you to post your GPS speed. You didn't give that info in your first post.

A side note, your 60 Merc cranks higher rpms than my 60 Johnson EFI, 4700-5300.

 

[RoccoST]

Ok...
Solas 11 1/8 x 13 at 4000rpm speed is 18.5 knots
Solas 11 1/8 x 14 at 4000rpm speed is 20.5 knots

Today I tried Mercury Black Max 10 1/4 x 14 pitch and my wot is 5700 and speed at 4000rpm is 19 knots, and question...what are you think what will I get with larger diametar like 10 3/8 x 14" (same alu black max) will I get more cruising speed, and probably lower wot rpm's?
tnx

 

[steelespike]

Have a prop shop add some cup to the 11 1/8 X 13.
Have you determined that 4000 is an ideal rpm for mileage.
Do you feel the fastest speed produces the best mpg.
When you increase pitch you make the throttle setting higher to achieve 4000.
While 2 mph will definitely get you there faster but at what throttle setting.
Did you just pick 4000 because your comfortable with the number or you feel the motor sounds less stressed?
If you really want to gain the best mpg you need a flow meter.Some just do flow others do real time mpg calculation.
It is possible that any one of the props you tried could produce the best cruising mpg when run at their ideal rpm.
Keep in mind the the difference in mpg of a good setup and a perfect setup would probably be measured in 100ths of a gallon.

 

[RoccoST]

Tnx Steele, of course I didnt pick 4000 rpm couse it looks fine...sound of the motor at that rpm's sounds less stressed!
Yes of course there are many parameters, and I am little playing with these propellers that I found optimum performance for my boat.
What I do now concluded that I was definitely a 13 "pitch is ideal measure, but I'm only interested in which diameter?
What I am most interested, is what is the difference in the surface of that larger area of New Saturn in compare to Saturn s/s SOLAS 11 1.8 x 13"
Is anyone have experience with this, is that the minimum difference or something that will reduce rpm's significantly.

 

[YoungMind]

For the 13P they both have the same Diameter. Both are good general purpose props and will serve you well. The Saturn will have have a slightly smaller blade area so might help a little better with TOP SPEED since that seems to be what you are concerned with. If you want a smoother ride at lower RPM then get the New Saturn since it will have slightly larger blade area.

 

[RoccoST]

Thanks YoungMind, I guess I'll go on New Saturn for better acceleration and cruising speed, do you agree with me that this is a better choice than Saturn?

 

[YoungMind]

Sorry I haven't checked in in a couple days. The New Saturn will have a larger blade area so it will help get the boat on plane a little easier and cruise at slightly lower RPM. The Saturn will help a little more with top speed since there will be less drag from prop face. So from there it just depends on which way you want to go. Both are made to give good all around performance and good fuel economy. Good Luck :wave:

 

[RoccoST]

Thanks!!!

 

[RoccoST]

I have another question so that I don't have to open a new topic ...
I'm interested in particular the following: what do you think that have been obtained if instead of SOLAS amita3 (alu prop) 11 1/8 x 13 "pitch I put on SOLAS New Saturn (ss prop) 11 1/8 x 13" pitch, under the same conditions,on the same boat, on the same outboard (mercury 60 efi, non big foot) with the same conditions at sea.
Existing prop (amita3) spinning 5700 rpm (just for information).
Tnx

 

[steelespike]

The supposed more efficient ss prop may load the motor more though it may help the boat to get upon the water better resulting in better speed.