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BF200 Propeller Size

K

k_m_thompson

Member
Gentlemen:

I have a 2002 BF200 (bought new in 2014, but that's another story) powering my 23' workboat.

It currently wears a 14x19 4-blade aluminum wheel. With a clean bottom and the boat running light, WOT only produces 4500RPM. I would prefer to stick with the 4-blade wheel, and don't want to change to a SS unit due to all the driftwood in our local waters (northern end of western Canada's Gulf of Georgia). Any suggestions of what pitch I should change to to be able to achieve a proper WOT maximum?

Regards,

Kerry Thompson
 
The general rule of thumb is ~250rpm gain at WOT for each inch of pitch removed. That would bring you back to a 14 x 15 or less. We repropped a 32ft power cat with twin BF175s a while back due to WOT only being around 5300. Went from 14.25 x 17's to 14.5 x 15's. Results were pretty interesting. We went from 4000rpm cruise giving 20knots and using 18.7gph to 4000rpm giving 19knts and using 13.3gph. WOT went to around 5800 as expected. The really interesting thing was the massive drop in fuel consumption for minimal loss in speed. What that means is that the smaller original prop diameter was giving a lot more prop slip than the slightly larger prop with lower pitch. I would do some prop slip calcs for your current setup and then have a think about your prop diameter as well as the pitch reduction when you change props. My feeling is that the Honda may not be as efficient when overloaded and you might see some nice fuel savings once you get it propped correctly. Spinning the engine faster with the correct prop loading is much better than spinning it slower with too much prop on the back.
 
How much does that boat weigh, loaded? Generally, I agree with Aliboy. If the boat is heavy, then you might want to come down to a 15" pitch on a 14.25" diameter prop. That is what I'm using on a 6,000 lb. 25' C-Hawk cabin boat with a BF 225. If it's lighter, than a 17" pitch may work, but I would still try the 15" pitch, first. You can't over rev that engine because it has a limiter that kicks in at around 6,200 rpm.
 
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