what prop to use?

[fordmugg]

hello im new to the forum and i have a question i have a 1974 17ft kona boat with a 115 mercury outboard it has what i think is a 19 pitch 4 blade. my question is i would like to get a little more top end ...the boat gets out of the hole real fast but only goes like 35 maybe 40 if trimed right.....so could i go to a 21 pitch and a 3 blade or stay with a 4 blade ? sorry im new to boats and any info will help...just want to go a little faster ............thanks

 

[Bondo]

Re: what prop to use?

Ayuh,......

Just like Everybody else,.....

You've Got to know the rpms at WOT,+ your Speed,.....

Without that Info,..... You'll only get Guesses.......

 

[steelespike]

Re: what prop to use?

Like bondo said we need actual prop size,max rpm and speed. (gps is best).
Don't make any prop change without this info.
Generally a 3 blade will produce more speed than a 4 blade.
You also should optimize your setup.Raise the motor verticle height to a point just before venting becomes a problem.An inch could get you 2 -3 mph depending on where your at now.This could also improve your economy.
If your getting 40 with careful trimming your pretty near the max depending on boat weight/style etc.

 

[fordmugg]

Re: what prop to use?

sorry like i said im new to all this so ill find out what rpm and speed it runs at WOT and then ill re post....i mean the thing needs a new prop anyways because its getting pitted on the blades like its eating a hole through it

 

[Bondo]

Re: what prop to use?

Ayuh,......

That sounds like cavitation Burns,.....

SS is probably Right,... With a New prop,+ some refining of your Set-Up,.....
You'll think you've got a Brand New Boat.....


Btw,......

Welcome Aboard to the forums here at iboats.com................

 

[fordmugg]

Re: what prop to use?

thanks as soon as i get the rpm and speed ill post back