longshanks
Petty Officer 2nd Class
- Joined
- Jun 12, 2006
- Messages
- 188
I am getting closer to having my boat dialed in, but I'm still not there yet. I have a bunch of props at this point, none of which are really perfect. My motor is a Merc 50 4-stroke, and the boat is around 1500lbs, aluminum skiff, with a small tunnel. I suspect this makes it somewhat of a funky rig to prop correctly. Motor is rated for 5500-6000 RPMs, and I have a smartcraft gauge, which gives me accurate RPMs.
Prop #1 is a Pirahna composite prop. I have 2 sets of blades that make it either 10 3/8" by 13 pitch or 12" by 11 pitch. Interestingly enough, both pitches give me approximately the same top speed of 29mph. The 13 pitch tops out around 5600 RPMs, while the 11 pitch tops out at around 6200 RPMs. While the 13 pitch is in the RPM window, it is pretty slow coming out of the hole, and doesn't really get up and go.
Prop #2 is a Quicksilver 11 5/8" by 11 stainless prop. This is the best performing prop I own, but it over-revs, causing my motor to beep and go into 'guardian mode'. I could probably rev it out to 6350 if I tried to, and I've had it up to 31mph at around 6100 RPMs. Very fast out of the hole, and I plan on keeping it around as a waterski/tubing/load prop. However, it is too touchy for my normal/light loads, especially with other drivers.
Prop #3 is what I bought to try and bring the revs down a bit. It's a stilletto stainless 10.5 by 12 pitch. I was surprised to find out that WoT is only about 5250 RPMs, and it pushes only around 28-29mph. I suspect this is due to the cupping of this prop, and although it performs well, I am too far out of my RPM window to keep this one. Anybody want to buy it?
None of these props cavitate, and I am certain that my motor is in the right position; I've tried it at several different heights. Any suggestions on where I go from here? I'd like to get a good prop for cruising, that revs very close to 6000 @ WoT.
thanks for your thoughts...
Prop #1 is a Pirahna composite prop. I have 2 sets of blades that make it either 10 3/8" by 13 pitch or 12" by 11 pitch. Interestingly enough, both pitches give me approximately the same top speed of 29mph. The 13 pitch tops out around 5600 RPMs, while the 11 pitch tops out at around 6200 RPMs. While the 13 pitch is in the RPM window, it is pretty slow coming out of the hole, and doesn't really get up and go.
Prop #2 is a Quicksilver 11 5/8" by 11 stainless prop. This is the best performing prop I own, but it over-revs, causing my motor to beep and go into 'guardian mode'. I could probably rev it out to 6350 if I tried to, and I've had it up to 31mph at around 6100 RPMs. Very fast out of the hole, and I plan on keeping it around as a waterski/tubing/load prop. However, it is too touchy for my normal/light loads, especially with other drivers.
Prop #3 is what I bought to try and bring the revs down a bit. It's a stilletto stainless 10.5 by 12 pitch. I was surprised to find out that WoT is only about 5250 RPMs, and it pushes only around 28-29mph. I suspect this is due to the cupping of this prop, and although it performs well, I am too far out of my RPM window to keep this one. Anybody want to buy it?
None of these props cavitate, and I am certain that my motor is in the right position; I've tried it at several different heights. Any suggestions on where I go from here? I'd like to get a good prop for cruising, that revs very close to 6000 @ WoT.
thanks for your thoughts...
