On 2007-12-09 21:36:03 -0500, Wayne.B said:

On Mon, 10 Dec 2007 01:51:15 GMT, Jere Lull wrote:

That the difference in efficiency between a dinky 12x8 spinning at 2500
rpms or more, and a 16x10 spinning at about 1200.

I understand you point. You now need less horsepower to achieve the
same boat speed because you have a more efficient prop, and are running
the engine in a more efficient power range. Was there any impact on
sailing performance?

I didn't sail Xan with the old engine/trans/prop, but expect there was
some "hit" with the larger 2-blade.

When we switched to a 16" feathering 3-blade, we noticed a significant
improvement under sail over the 15, mostly in low winds where we're
able to sail at 3-4 knots in conditions that we used to motor in. It
"feels" like we point a bit better under all conditions, but I can't
document that.

Also measured a slight decrease in fuel efficiency after the switch,
maybe as much as 15%, but that's only 0.26 to 0.33 gph at our normal
cruise.

--
Jere Lull
Tanzer 28 #4 out of Tolchester, MD
Xan's pages: http://web.mac.com/jerelull/iWeb/Xan/
Our BVI trips & tips: http://homepage.mac.com/jerelull/BVI/