How to go from 11" Dia. to 13" Dia.

[sportyinc]

I purchased a V176 Glasstron with a 115 HP L6 Merc.
I haven't installed a tach yet but I'm worried about the prop.
I measured the prop on the motor and it is 11"X21P.
It is also pretty dinged up. I know how to rate different pitch props, but I don't know how to adjust for the different diameter. Even if I had a tach, the prop is too banged up (IMO) to give an accurate reading.
The manual say this motor takes a 13" prop.
What would be a ballpark equivalent in 13" Dia. compared to a 11"X21P prop?
I'm seriously considering a 4 bladed Alum. prop.

Thanks in advance,
sportyinc

 

[steelespike]

Re: How to go from 11" Dia. to 13" Dia.

Did you measure diameter from the center of the bore to the tip of a blade and double it?Or was it stamped on the prop?
See if you can get the prop repaired and get a base line test of the max rpm and speed. Its important to have a tach and gps to get the best idea of what you need and to tell if the selection is right.hwsiii has a form with the info he would need to help you select a prop.See if you can find it in one of his posts.We also need the details on your boat weight,style,Deep V? etc.

 

[sportyinc]

Re: How to go from 11" Dia. to 13" Dia.

I measured from the center of the prop shaft. It is 5-1/2 from center to tip of blade.
The number on the prop: 48-32746A3 21P indicates a 13"X21P Aluminum propeller.
So obviously, this is a prop with A LOT of wear and tear.

Instead of putting more money into this prop, I think I will buy a new one and test it.
Now I just have to rent a torch to get the old one off.

 

[steelespike]

Re: How to go from 11" Dia. to 13" Dia.

Have you tried PB Blaster to loosen things up sometimes works.
I guess we can assume the prop has been there all along and worn out.
obviously no sense repairing.

 

[henrye718]

Re: How to go from 11" Dia. to 13" Dia.

So obviously, this is a prop with A LOT of wear and tear.

Instead of putting more money into this prop, I think I will buy a new one and test it.
Now I just have to rent a torch to get the old one off.

JB weld and some sand paper might fix it enough to get a 2 min test run.

Piranah props has a blade exchange program I dont think you can go wrong with it, they let you test for the price of shipping.

See the link it explains the program...

http://www.piranha.com/exchange.php