OEM prop size

[David]

Any O'Day 30 owners (mine is an 1984, Universal M-20, 2cyl, 16hp.powered)happen to know the OEM propsize? Mine now has a 16/9, but would seem to keep the engine rpm's down to low (cruising speed: 6.5 @2200 rpm). If you have any input you could share with me I'd more than appreciate it.

 

[Peach17794]

Prop size

My '84 O'Day 30 has the M-18 14 Hp engine. My prop is 15 x 9 which makes sense for slightly less engine. Lately, I need a clean hull to get it up to 6.5 Kts. I also have lot's of prop walk in reverse, I've considered changing prop more for that reason. Let me know what you come up with.

 

[TT23844]

Michigan Wheel

has an on-line propellor calculator < http://www.miwheel.com/ >Get all the data for your boat ( incl. beam at WL, LWL, displacement, rated HP of engine @ RPM, gear reduction etc. Shaft size & distance between the shaft and the hull is also required to determine the max . diameter wheel & necessary tip clearance ) and enter it into their program and you'll get a recommendation via e-mail in a few days. Your engine will only develop its' rated HP at a certain RPM & if the prop loading is too great and your engine can't develop that RPM at full throttle the engine won't make 16 HP or whatever.Oh, I think you also have to specify the number of blades as well as pitch & diameter.