Thanks Skipper It seems that if we are figuring on screwing ourselves through the water (if you will pardon the expression) at 4 knots the propeller should be advancing so as not to "strip the thread" If it were turning a 500 rpm it would turn 500 x 60 = 30000 rev in one hour. Each rev would be 4/30000 nautical miles or 4/30000x6080x12=9.728in This would be the ideal prop pitch. If the prop spins at say 1000 rpm the pitch would be 9.728 x 500/1000=4.864in etc. I found a interesting site on prop design here is the link http://www.boatfix.com/how/props.html
Thanks for the information Captain Jim Sadler Skipper sailing vessel Pelican -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] sion.com]On Behalf Of Doug Kelch Sent: Thursday, August 30, 2007 6:29 AM To: For and about Montgomery Sailboats Subject: Re: M_Boats: M-15 Prop pitch The Honda 2 hp 4 cycle uses a plastic prop. There was an article in Messing about in boats about how to change the pitch by clamping the tip of the blade, using a heat gun at the base and twisting in the desired direction. The tip clamp can include a longer piece of wood to help set the desired angle. I was going to try it but my local dealer was out of stock on new props and I didn't want to try it on the only one I had. I subsequently lost interest as the Honda works so well as is. I do believe that we could get better performance in waves with a more power oriented prop than comes as standard. Thanks Doug Kelch Gary M Hyde <[EMAIL PROTECTED]> wrote: M15 theoretical hull speed is 4.8 knots. The Honda 2hp only has one size prop available as far as I know, and it works pretty well on the M15. If you back off the throttle to about 4 knots, you can get ~28 nautical miles per gallon in calm waters. --Gary Hyde 2005 M17 sailboat #637 'Hydeaway 2' We can't change the wind, but we can trim our sails. On Aug 29, 2007, at 12:24 PM, [EMAIL PROTECTED] wrote: > > In a message dated 8/29/2007 11:24:59 AM Mountain Standard Time, > [EMAIL PROTECTED] writes: > > Thanks for all of the great advise on outboard motors. I have > narrowed it > down to 4 cycle, long shaft, 2 to 3 HP. > > Have any of you skippers used a special prop on the motor? Seems > like the > prop pitch and diameter needs to match the the shaft RPM, motor > power curve > and the M-15 haul speed. What is the haul speed of M-15? Since > the Pelican > is still in keel surgery I have no way to make a speed run. > > sincerely > Captain Jim Sadler > skipper sailing vessel Pelican M-15 > > > > _______________________________________________ > http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats > > > > I doubt that prop pitch is very important on such a light boat. Those > considerations are more for a heavy displacement yacht. > > > > ************************************** Get a sneak peek of the all- > new AOL at > http://discover.aol.com/memed/aolcom30tour > _______________________________________________ > http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats --------------------------------- Luggage? GPS? Comic books? Check out fitting gifts for grads at Yahoo! Search. _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
