prop size

[1bigdog1]

I would like to ask this question again... For a 19.5 ft. boat with a v-hull, and a 235 evinrude what prop size would you suggest? The guy I bought the boat from says with a 13 1/2 18 pitch he was running 65 mph. I was thinking this boat needed more like a 14 to 14 1/2 with 2 pitch.<br />Whats your thoughts and opinions?

 

[roscoe]

Re: prop size

Changing prop size and/or pitch should be determined by your rpm's, and your desired holeshot and top speed. Engine rpm being the most important, as too high or too low can damage motor.

 

[Dhadley]

Re: prop size

To run 65 mph at 10% slip with an 18" pitch you will have to turn the motor a tad over 7700 rpm. <br /><br />Since he was running a 13 1/2" diameter he may have been using a V4 gearcase which has 2:1 gears. That means with 10% slip he was turning the motor over 8200 rpm. <br /><br />If he was using a 1:1 gearcase he would have only been turning about 4150 rpm. <br /><br />Any of these scenarios sound about right?<br /><br />Lets start with, as suggested, the rpm and speed with how you are going to run it now. To establish your baseline try any prop in the 19" to 20" range and we'll go from there.<br /><br />Good luck!