I could use some guidance on choosing a new prop.
Boat:
1994 Bass Tracker TX-17
17' Aluminum Hull
1440 lb. net weight?
Motor:
2004 Tracker/Mercury 50 ELPTO
Recommended WOT Range: 5000-5500 RPM
Gear Reduction Ratio: 1.83:1
Current Prop: 10-7/8" x 11" (48 85632A40 11P)
Current WOT: ~5800 RPM
Current Top Speed: ~30 mph
Boat Load During Test: High side of average usage (3 people, full fuel and gear).
Gross Weight During Test: Guessing, about 2,000 lbs.
The motor was originally on a heavier Nitro boat and the prop chart I found seems to support the original prop choice. However, on my boat, it appears that I need a higher pitched prop to get the RPMs down within the recommended range.
I've included an image of the service manual prop chart for the 1998 version of my motor. I'm assuming it is accurate for my 2004 model (everything else in the service manual seems to match my motor exactly).
The chart seems to suggest a 13" pitch prop for my size boat, based on weight and length. Based on my tests and the rule of thumb that I have seen (150-200RPM per 1" pitch change), a 13" pitch will likely lower the RPMs to 5400-5500 RPM, right in the magic range.
I've read that diameter won't likely make a significant difference, but I do seem to have choices. Not sure which way to go here.
Also, should I generally rely on my boat's built in tachometer for prop selection, or do I need a more accurate gauge?
My ultimate goal is to have average performance, probably leaning towards top end speed as opposed to hole shot power, but mainly to get the RPMs within, but to the high side of, the recommended range.
So, based on the above, I'm thinking a 13" pitch prop is what I need, but I'm not sure about diameter. I would appreciate any comments on my approach and whether I'm missing anything that I should be considering.
Thank you,
Mike
Boat:
1994 Bass Tracker TX-17
17' Aluminum Hull
1440 lb. net weight?
Motor:
2004 Tracker/Mercury 50 ELPTO
Recommended WOT Range: 5000-5500 RPM
Gear Reduction Ratio: 1.83:1
Current Prop: 10-7/8" x 11" (48 85632A40 11P)
Current WOT: ~5800 RPM
Current Top Speed: ~30 mph
Boat Load During Test: High side of average usage (3 people, full fuel and gear).
Gross Weight During Test: Guessing, about 2,000 lbs.
The motor was originally on a heavier Nitro boat and the prop chart I found seems to support the original prop choice. However, on my boat, it appears that I need a higher pitched prop to get the RPMs down within the recommended range.
I've included an image of the service manual prop chart for the 1998 version of my motor. I'm assuming it is accurate for my 2004 model (everything else in the service manual seems to match my motor exactly).
The chart seems to suggest a 13" pitch prop for my size boat, based on weight and length. Based on my tests and the rule of thumb that I have seen (150-200RPM per 1" pitch change), a 13" pitch will likely lower the RPMs to 5400-5500 RPM, right in the magic range.
I've read that diameter won't likely make a significant difference, but I do seem to have choices. Not sure which way to go here.
Also, should I generally rely on my boat's built in tachometer for prop selection, or do I need a more accurate gauge?
My ultimate goal is to have average performance, probably leaning towards top end speed as opposed to hole shot power, but mainly to get the RPMs within, but to the high side of, the recommended range.
So, based on the above, I'm thinking a 13" pitch prop is what I need, but I'm not sure about diameter. I would appreciate any comments on my approach and whether I'm missing anything that I should be considering.
Thank you,
Mike