prop help

trophy striper

Recruit
Joined
Dec 20, 2008
Messages
5
I currently have an 13x19 aluminum 3 blade. Found a great deal on a 13.5x19stainless 3 blade. Boat runs fine with current prop was wanting to install the stainless and keep the aluminium for a spare. What would the effect be of this change if any

Thanks for the help
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: prop help

We have absolutely no idea since you didn't tell us what boat, what engine, what your current observed wide open throttle rpm is, who the manufacturers of these two props are, what model the props are and at least what material they are. Prop design is not just diameter and pitch but includes rake, cupping, progressive pitch, blade shape and a whole host of other characteristics all of which have different affects on performance. If both props were identical designs except for diameter, 1/2 would not be noticeable. But that 1/2 inch means there other differences in that prop design so without any data, we have no clue what would happen.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: prop help

ST is being a little harsh but if you give us as much info as you can, don't worry about being long winded.Any prop change can be a gamble.when changing materials it adds even more variables.
 

trophy striper

Recruit
Joined
Dec 20, 2008
Messages
5
Re: prop help

sorry for the lack of info the boat is a 1996 1802fj trophy walkaround the motor is an 1996 120 hp force. prop on motor now is oem aluminium 13x19 want to insall 13.5 19 us marine stainless. wot with aluminium installed is 5000 rpm at 38 mph on gps.

thanks again for your help
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: prop help

I'm a little outside of the experts.But My suggestion is to check into the Hustler props.They give close to ss performance for al prices.You could buy 2 for the cost a ss.If I was buying the Hustler I would start with the same pitch.I'm pretty sure it will increase overall performance.
The experts may feel differently.
 

trophy striper

Recruit
Joined
Dec 20, 2008
Messages
5
Re: prop help

sorry for the lack of info the boat is a 1996 1802fj trophy walkaround the motor is an 1996 120 hp force. prop on motor now is oem aluminium 13x19 want to insall 13.5 19 us marine stainless. wot with aluminium installed is 5000 rpm at 38 mph on gps.

thanks again for your help

life isn't about waiting for the storms to pass
it's about learing to dance in the rain :)
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: prop help

See how easy that was! Six responses could have been reduced to two (plus those from other contributors). The 1/2 inch increase in diameter on a prop of similar design will likely not be noticed. However the difference in prop design is a different story. Since the stainless prop will likely be more efficient, you might gain 1-2 MPH on top end, hole shot may or may not change and WOT rpm may decrease slightly. The only way anyone can tell you for certain what the outcome would be is if they have the identical boat, identical setup, identical load and identical props. Anything less than that and it becomes a trial and error situation. Your original setup appears close so to what degree the stainless prop changes things is hard to tell.
 
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