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Prop Question 2002 MFS25a

snookwhaler

Regular Contributor
Currently running a 10/11 turning point prop. Max. RPMs with full fuel and just me in the boat only 5300 to 5500 RPM under optimal conditions. I had 3 adults out this week in the same boat with about the same fuel load and could not get over 4700 RPM. So, obviously over propped for this heavy rig/small motor.

Is it safe to assume that I should be running a 10/10 or maybe even a 10/9 to take advantage of the extra RPM when I need it? Also looking at a Solas Amita instead of the turning point as I have had good luck with those in the past.

Most of the time a comfortable cruise seems to be 4200 to 4300 with just me in the boat.
 
Ideal WOT RPM is 5000-6000. If staying with the same prop configuration, you need about 2 inches less pitch. Just don't run full WOT when you don't have any load in the boat, to stay below 6000. If you switch between 3- and 4-blade props, everything changes.
 
That's what I figured. I just wanted to hear someone else say it. I just ordered a 10/9 3 blade Amita. Thanks for the quick response!
 
Thanks again! That was the ticket! I got the prop yesterday and put her in the water. Now I'm getting just over 5800 RPM at WOT which actually feels right. Everything about the boat is snappier now. I did not even think to check the speeds, but at WOT it is definitely faster. Different boat/engine now...

Seems that 4700 to 4800 RPM is the all day cruise RPM now.

I almost went with a 10/10 before posting here. I'm glad I didn't now! The 10/9 was the ticket...
 
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