Prop recommendation for a 18" bowrider?

photographer

Seaman Apprentice
Joined
Jul 25, 2015
Messages
33
I have a 18" Wellcraft 180 Sportsman with a 115HP Yamaha. My current prop is a 13 1/4 - 17. I would prefer better mpg than power. I use the boat with my kids cruising around.

Should I change it to a 19 pitch prop?
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Best economy is obtained when the engine can rev freely to it's top RPM band (recommended by MFG) with normal load. So, what is your RPM and MPH at WOT now with typical load? If it is close to top RPM then going to higher pitch could cause the engine to lug which can cause internal engine problems shortening it's life. If the engine can over-rev now past the top RPM's then definitely go to the next higher pitch..
 
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steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
As suggested what is your present wot rpm and gps speed.Once we know your wot performance is best
you can operate at whatever throttle setting you prefer.
MPG difference from a good setup and a perfect setup would be difficult to tell.
If you want to find the best mpg a flow meter is the away to go some can give realtime mpg.
Best overall cruising speed could be from just on plane to about 1000 rpm higher.
 
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