Should I change props

[stubbsboogie]

I am wonderin if I should change propellers. I have a 1998 Glastron GS 180. Running a 2001 Yamaha 100hp 4stroke.
At WOT turing about 6200 or 6300 rpms at 38 mph.
I am currently running a 13.5x16 stainless steel propeller.
While I am comfortable at this top end speed my buddy keeps telling me that I am turning to many rpms and will get more speed at less rpm if I go to a higher pitch prop. Also get better gas mileage, as well as lengtening my engine life.
So shold I switch to a higher oitch.
Thanks so much guys, I-boats is great.

 

[Mkos1980]

Re: Should I change props

What is the factory rpm range for that motor? That will tell you if you need to change. It the rpm range is below then go up a pitch. If the rpms are higher then the range then go down a pitch.

 

[stubbsboogie]

Re: Should I change props

The recomended RPM is 6000.
If I go up a pitch or two will I loose much hole shot, mostly I pull skiers and tubes. Cruise mainly around 25 or 30 anyway

 

[Mkos1980]

Re: Should I change props

In the event you see wide open throttle alot you will have to move up in pitch. You will loose a little pulling power, but I'm not sure how much with the motor and boat combination you have. If you do ski alot which seems you do and you stay below your 6K, keep with what you have.

 

[steelespike]

Re: Should I change props

If you drop an inch I don't think it will kill your hole shot.It probably improve your mileage simply because you will be going a little faster for a given rpm.
your motor will be happier turning slightly less rpms per mile.You may not be able to tell any fuel savings etc.
If you tend to run with a load of people and gear you may want to stay with your present prop but you must stay at 6,000 or less.

 

[parrilladk]

Re: Should I change props

Staying with the same pitch, but changing to a 4 blade will increase your hole shot, increase your mid range speed and probably lose a hair in top speed. All of this at lower rpm's.

 

[stubbsboogie]

Re: Should I change props

I think maybe I should move to a 17 pitch. But I really do not want to spend 400 bucks for a stainless steel will I see a noticable difference if I go with an aluminium prop? Cause that would be a whole lot cheaper. and I will still have my SS if I need to pull lots of wieght. I do see WOT quite a bit on longer runs down the rivers in my area. There is not much to hit so with the prop in most areas so do you guys think that the aluminium will hold up ok.
Thanks again for all the help guys.

 

[Irv964]

Re: Should I change props

I think maybe I should move to a 17 pitch. But I really do not want to spend 400 bucks for a stainless steel will I see a noticable difference if I go with an aluminium prop? Cause that would be a whole lot cheaper. and I will still have my SS if I need to pull lots of wieght. I do see WOT quite a bit on longer runs down the rivers in my area. There is not much to hit so with the prop in most areas so do you guys think that the aluminium will hold up ok.
Thanks again for all the help guys.

I believe I got SS performance out of an Aluminum prop? Read my link below about Turning Point props, not saying they are the best or you should get one, just letting you know that there are some good aluminum ones out there. I have heard good things about the Solas Rubex series as well.
Also you will see links in some threads that talk about engine height etc, make sure you read those too, they may apply to you? Good Luck......Irv964
http://forums.iboats.com/showthread.php?t=269778

 

[steelespike]

Re: Should I change props

I think maybe I should move to a 17 pitch. But I really do not want to spend 400 bucks for a stainless steel will I see a noticable difference if I go with an aluminium prop? Cause that would be a whole lot cheaper. and I will still have my SS if I need to pull lots of wieght. I do see WOT quite a bit on longer runs down the rivers in my area. There is not much to hit so with the prop in most areas so do you guys think that the aluminium will hold up ok.
Thanks again for all the help guys.

When going from SS to AL all bets are off.Too many variables.
The Hustler Turning point mentioned above may be close enough but again the variables.