John: When you get a chance, I'd be curious to know how much rake you have. One way to measure it would be to level the boat fore and aft, then hang a weight from the main halyard, and measure out from the mast onto the boom. Otherwise, how do you quantify "a lot of rake"? It appears to me that extra mast rake would shift the center of effort aft, creating weather helm (drive from the main causes boat to twist into the wind), and there would be an optimum amount of weather helm that would suck the boat to weather, as long as the force of counter steer from the rudder was still lifting and not stalling. So a big lifting rudder would help there. But mast rake is also going to affect the interaction of the headsail and main, so there may well be more at play that just a center of effort issue. But in addition to mast rake, you have the shape and cut of the main to consider (I have a full batten main with extra roach.....do I need as much rake as someone with a regular cut sail?), as well as the interaction of the mainsheet and traveler positions (twist), not to mention the size and lead position of the headsail, rigging tension, and lastly, total weight on board and fore and aft balance of the extra weight. Another thing I recently read somewhere was the importance of a clean bottom. It was mentioned that an frost on the wings of an airplane hurts the lift and keeps it from flying.....and scum and growth on the keel and rudder of a sailboat does the same thing. My interest in all this is not for racing, but more of an academic exercise that would allow the boat perform better to get where I'm going sooner. Why tack twice if you only have to tack once? That...plus these boats have a reputation as being good sailors. I'd like to uphold the lady's honor! Howard On 3/26/04 11:18 PM, "Saltm17@aol.com" <Saltm17@aol.com> wrote:
Doug,
I can't explain how it works, but Jerry told me once that the M17 need some serious mast rake and weather helm to really perform to windward (not sure about the M15 or M23). It has something to do with the deep rudder (after being carefully faired) adding some lift. I just played around with the amount of rake and when I found the right amount, the boat really responded. That was the key to going fast to windward, and patience and boat trim were the keys to downwind speed. Sounds simple, but it took me quite awhile to figure it out.
John _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats