JP Richmond
Recruit
- Joined
- Aug 1, 2010
- Messages
- 5
On prop selection, Here's what I have to deal with, and why I'm thinking of a pitch change:
Polarkraft 1668 jon with Yamaha 30LF tiller steer, both 1989 models.
Boat, with added weight of "fix-ups" is 380 lbs., 515 lbs with (135 lb) motor.
Typically, there are 2 of us on board, adding 350 lbs, 400 with gear, so now we're at 900-plus lbs. total
We pull a tube in creeks a lot, sometimes put in at Beaufort NC and cross choppy Shackleford Slough to Shackleford Banks, inland side. We often have 4 on board (total 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 specs a 9'7/8" dia. x 11-1/4" pitch, but the motor is also spec'd for a 12 and 13 pitch. The previous owner put a (now spun) 13 pitch on it. He was usually fishing alone and never pulled with it.
One chart I found spec?s the 13-pitch only for up to a 15? boat versus our 16', but I don?t know how accurate that source is. We want another aluminum prop, considering the (shallow, messy) places we sometimes take the boat.
I thought we'd be well-served to reduce the pitch to a 12. Seems I'd get better pulling power without losing speed. Thing is, we don't have a tach, and rpm's seem to be a big deal in choosing a prop. I don't really understand the relationship between a change in pitch and speed, rpm's, pulling power, hole shot, ....
Any suggestions? Thanks, John Pride
Polarkraft 1668 jon with Yamaha 30LF tiller steer, both 1989 models.
Boat, with added weight of "fix-ups" is 380 lbs., 515 lbs with (135 lb) motor.
Typically, there are 2 of us on board, adding 350 lbs, 400 with gear, so now we're at 900-plus lbs. total
We pull a tube in creeks a lot, sometimes put in at Beaufort NC and cross choppy Shackleford Slough to Shackleford Banks, inland side. We often have 4 on board (total 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 specs a 9'7/8" dia. x 11-1/4" pitch, but the motor is also spec'd for a 12 and 13 pitch. The previous owner put a (now spun) 13 pitch on it. He was usually fishing alone and never pulled with it.
One chart I found spec?s the 13-pitch only for up to a 15? boat versus our 16', but I don?t know how accurate that source is. We want another aluminum prop, considering the (shallow, messy) places we sometimes take the boat.
I thought we'd be well-served to reduce the pitch to a 12. Seems I'd get better pulling power without losing speed. Thing is, we don't have a tach, and rpm's seem to be a big deal in choosing a prop. I don't really understand the relationship between a change in pitch and speed, rpm's, pulling power, hole shot, ....
Any suggestions? Thanks, John Pride