Prop for Ribcraft 6.8 and BF225 Honda

[PTNICK]

Ive been looking at prop calculators on the web and it seems that something around 14x19 is recommended. Boat and engine is 2800lbs empty, 300 lt fuel,
3 people max plus camping and photo gear, maybe 4200 lbs all up. (1900kg)


Stainless prop. 4 blade or 3 blade? Diameter? pitch?

I’m less interested in max speed than I am economy and mid renge responsiveness in rough water.

All advice greatly appreciated!

[jwalker]

Keep an eye open on eBay for a Torqueshift, they pop up occasionally.Two came up at once a few weeks ago. They're not made anymore but parts can be got. They'll start at about 13" pitch and pitch up according to your load, ideal for what you need.

Alternatively, I'd go with your guess of 19" for a starting point. Borrowing one would be good if you can manage it.

[PTNICK]

Thanks, JW. I’ll check eBay. Any experience with 4 blade props?

[jwalker]

Originally Posted by PTNICK

Thanks, JW. I’ll check eBay. Any experience with 4 blade props?

No, sorry, extra blade equals extra drag. Unless you're carrying such a load that your present prop breaks loose because the blade's area is too small, then I don't see an advantage.

[PTNICK]

Makes sense. To me. Dou u run alloy or ss?

[jwalker]

Originally Posted by PTNICK

Makes sense. To me. Dou u run alloy or ss?

Stainless. One boat came with stainless and the other only has stainless available so an easy choice. In the past I've run with alloy props but, generally, they have been general purpose in their blade type. My experience is that some props are awful and some are excellent with plenty inbetween. It's tricky and expensive so I reckon most folk try something, if it seems ok they stick with it.

Later on they'll convince themselves that it's the best thing since sliced bread!

[jwalker]

Originally Posted by jwalker

Keep an eye open on eBay for a Torqueshift, they pop up occasionally.Two came up at once a few weeks ago.

There ya go, on Craigslist. If your Honda uses the standard spline you're in luck.

https://buffalo.craigslist.org/bpo/d...759350153.html

[PTNICK]

Thanks JWALKER, ILL CHECK IT OUT.

[PTNICK]

I just got in from my first—brrr cold!—sea trial with my new-to-me 2008 Ribcraft 6.8 with Honda 225.

6100 rpm, 51 mph. Prop 4-14.5x17 ss Turning Point prop. I was incredibly pleased, especially that the engine ran so well. He speed/rpm target seemed very good for a lightly loaded boat: 2 up, 40 gallons fuel.

4.9 gpm @ 30 mph. 3.8 @ 40 mph.

[jwalker]

I'm presuming that's miles per gallon not gpm. It equates to the 'standard' rib usage of approximately 1lt per mile when cruising so pretty much as expected. Speed seems about right also. It looks as though you're all set to enjoy your boat.

[PTNICK]

Yes,miles per gallon. Thanks.