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2006 BF50 Prop Question

D

DMHOutboard

New member
Hello All,

I'm new to the forum.

Recently I purchased 32ft house boat that is running what I think is a 2006 BF50. The boat is heavy, around 8-11,000 lbs. The current cruise speed at 3000-3500 rpm is 5-7mph.

Id like to move top end to 10mph at 3000.

The prop is chewed up a bit and I like to replace it with the prop that will provide me the best top end.

Does anyone have a suggestion on what prop would provide me the greatest top end pushing this weight?

Thank you,
 
iang6766 said:
You're looking to almost double the speed, I don't think that's possible without a lot more horsepower
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I have considering this a 75 would do the trick.

However, in an attempt to use the equipment I have, my thought is that with an undamaged prop perhaps I'll gain 1 or 2 mph. Which gets me closer. A couple more mph and I'm there.
 
I am also doubtful that motor will do that at 3,000 RPM, however, with that heavy of a load, I would recommend a stainless prop. Stainless has less flex than aluminum, especially when under heavy load.

Higher pitch will give you higher RPM and faster speeds, lower pitch will give you more thrust and a slower top end. You need to determine what your current prop is, it is stamped on the side of the prop. Tell us that and you may get better direction.
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eneusiis said:
I am also doubtful that motor will do that at 3,000 RPM, however, with that heavy of a load, I would recommend a stainless prop. Stainless has less flex than aluminum, especially when under heavy load.

Higher pitch will give you higher RPM and faster speeds, lower pitch will give you more thrust and a slower top end. You need to determine what your current prop is, it is stamped on the side of the prop. Tell us that and you may get better direction.
.
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Thanks.

I'm not at the boat currently. I'll send the pitch when I'm able.

Does anyone know what max RPM that the engine can safely be run for long periods of time?
 
You can run that motor all day at 5000 rpm. Just a correction, lower pitch will give higher revs and less thrust, the opposite for higher pitch. At 3000 rpm you are not maximizing the torque of the motor, you need to get it to rev at 5400 plus at wide open throttle, again, I think the load you're trying to push is too great.
 
iang6766 said:
You can run that motor all day at 5000 rpm. Just a correction, lower pitch will give higher revs and less thrust, the opposite for higher pitch. At 3000 rpm you are not maximizing the torque of the motor, you need to get it to rev at 5400 plus at wide open throttle, again, I think the load you're trying to push is too great.
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Thanks for the correction, after writing that I was in a meeting and thought, I said it wrong.
 
eneusiis said:
Is 3,000 RPM what you are getting at WOT?
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I'm not at the boat however last time I drove it I was at 5,000+. I can't be entirely sure however do understand why your asking. I believe it ran to WOT ok. Due to the prop condition it had a vibration.

3000-3500 seems to be the point where the boat was at it's displacement speed. It began to plane reaching 4-5,000.

After all the comments it's clear that I can likly accomplish my goal simply by putting a prop on that is not chewed up and increase my rpm.

I'll follow up with my findings when I'm back at the boat.

Thanks all for helping me sort this out.
 
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