Honda BF250 prop question

[grey2112]

So, took my Cobia 250 WA out for the first time yesterday to break in the new Honda BF250 motor.

Hole shot seemed pretty good and got up on plane quickly.

I'm not the best yet at proper trimming, but felt I was about in the right place.

At WOT in slightly choppy seas I was getting max 6000 rpms and 39.5 MPH according to GPS.

Granted, this is a brand new engine and I assume it may get better with age after all broken in, but I'm wondering if my prop isn't the one it really needs.

Specs:

Length at around 25 feet, but add 2 feet for bow pulpit

Has hardtop which may contribute to a little loss of speed

Beam is 8'6"

Weight dry is 3750

138 gallons of fuel (I had full fuel tank yesterday)

Weight of Honda motor is 622 pounds, has 30" shaft

Two Group 24 1000CCA batteries in rear transom box

Two people on board total weight for both of us about 425 lbs

10 gallons of fresh water in berth area

Current prop that the dealer installed with the Honda is a Solas SS 14.25x17 3-blade

I have a spare aluminum prop from my KeyWest that is a 14.5x19 3 blade and was wondering if I could use it - maybe try it out with the higher pitch and see if it makes a difference.

Otherwise, what would you recommend for a prop? Speed isn't important as much as efficiency at cruise. I like to get good MPG. My use is mostly going to be cruising at around 28-30 mph, 90% of the time it will be just me, the wife, and fishing gear. But there will be times when I'll have 4-6 people on board with at least 3 of them having dive gear, two tanks each, etc.

Thanks for the help!

 

[chawk_man]

I would go ahead and try the 14.5 X 19 as long as it fits properly to see if you still get 6000 RPM or very close to it. If so, then it demonstrates that you have some room for max efficiency. In general, you want as much prop as you can get and still be right around the 6000 rpm level. On a slightly heavier 25 ft. C-Hawk (almost identical to a Parker 25 XL modified V hull) powered by a BF 225, my optimum prop is 14.25 X 15.

Someone else will need to chime in about the differences in efficiency between a 3 blade prop and a 4 blade prop - that's above my pay grade.

 

[Talklessridemore]

What you have now, works fine. 3 blades 17 solas. If you gonna add more weight on yur boat , you may have to go with 16 or 15 pitch.

 

[grey2112]

Roger that - getting 40mph at WOT with full tank, scuba tanks, 3 people - can't really ask for more, and I cruise at 28-30 most of the time for best ride and fuel economy, so I'm happy with that.