Too much, too little or just right?

[Moody Blue]

Boat, a 1970 15 1/2 ft fiberglass Wilker. Heavy deep-v hull.

Motor, 1970 Merc 800 with power trim.

Prop on the motor now is 12 3/4" dia x 17" pitch.

Have not had the boat in the water yet but want to be close on the first try. I'm thinking I am a little under propped but would like some other opinions.

Motor spec is 4800 - 5300 RPM.

WHat say you?

 

[steelespike]

Re: Too much, too little or just right?

You can't make best guesses dealing with props.You need to run the boat and get the max rpm and speed preferably by gps.You shouldn't make any prop changes without a tach and this info.

 

[Moody Blue]

Re: Too much, too little or just right?

Its going to be awhile. Got some work to do on the boat and motor.

Hoping to be "close" on the first try.

Is there not a general rule of thumb to follow?