'89 Yamaha 30LF prop pitch change?

[JP Richmond]

I'm thinking of a pitch change:

Polarkraft 1668 jon with Yamaha 30LF, both 1989 models.

I spun my prop last time out.

Boat, with added weight of "fix-ups" is 380 lbs., 900 lbs with motor, 2 persons and gear.

We cruise creeks at 75% -plus WOT (or so), pull a tube, sometimes have 4 on board (ttl 1250 lbs), but after last Saturday will probably not have one of them on the tube! That's when the prop spun, after we'd (30 min. earlier) snagged (hard) something in the water.

The Yamaha book (that came with it) specs a 9'7/8" dia. x 11-1/4" pitch, but the motor is also spec'd (per Yamaha site) for a 12 and 13 pitch. Prior owner put a (now spun) 13 pitch (aluminum) on it. He was usually fishing alone, and never pulled with it.

I thought about reducing the pitch to a 12, hoping to get more pulling power and rpm's without losing speed. We don't have a tach, and that seems to be a big deal in choosing a prop. Do I need a Tiny Tach to evaluate a change in pitch and speed, rpm's, pulling power, hole shot, ....

Any suggestions?

Thanks,

John Pride

[boats.net]

Checking rpm's is the only way to make sure it is running within rpm range(4500-5500 rpm's at full throttle), You would want to stay at high side of rpm range for better hole shot.