John: A little rake is a good thing: see remarks by Jerry Montgomery below. A few typos were corrected and references to "death traps" were eliminated. steve Steve R. M-15 #119 Lexington, KY ************************************ Date: 18 Sep 1997 If you have too much helm it means that your mast is raked too much, even though the 17 sails best upwind with a fair amount; maybe about a foot, depending on your sails. I always tuned the mast by raking it back until I had a little helm; just a light "power steering feel. Jerry ************************************ Date: 24 Jul 1998 Try raking the mast to pick up a bit of helm, even in light air as long as you have a little heel. The 15 and 17 both will go faster upwind and point higher if you get the mast rake right. In a drifter, sit to leeward to get the heel. Do this mast adjustment in stages until you go too far, then back off. Jerry ************************************ Date: 10 Dec 1998 Leave the 15 rig a little loose. Forestay tension will come from load on the mainsheet, that way, when you ease the mainsheet (light air or a reach) the luff of the jib will relax a little and the sail will become fuller. This is an advantage of a bendy, 3/4 rig. If you pre-load the standing rigging you won't have this advantage. The reason that slack rigging worked on the Windmill, and many other triangle-rigged boats, probably including the 15, is so that on a run or stalled-out broad reach the mast can flop forward which will make the boat go faster. On the wind, the forestay will determine the mast rake, and nearly all well-designed boats will sail better upwind with the mast raked a fair amount. Notice the "well designed"- some boats will pick up a heavy helm before the optimum rake is reached. To simplify, as a generality, boats will sail upwind faster with the rig raked aft, and they will sail off the wind faster with the rig leaning forward slightly. If you can dig up an old copy of PERFORMANCE ADVANCES IN SMALL BOAT RACING by Stuart Walker (1969, W.W. Norton), it will explain this, and a zillion other interesting things. This book was one of my bibles about 30 years ago and things haven't changed much. I only raced the 15 a few times (and against pretty lazy fleets) and don't claim to know the boat that well in terms of speed potential, but I tune boats by playing around with mast rake until I have a light weatherhelm on the wind in light air with the boat heeled a little. Sit way forward and on the lee side. Don't even bother until you get the new sails; it's impossible to tune a boat right with bagged-out sails because no matter what you do the boat won't go upwind. Hope this helps. Jerry ******************************* Date: 06 Jun 2000 I can only guess at the mast rake, but I can tell you how to set it up. You want a little weather helm upwind at all times. In light air, sit on the lee side of the obat, if needed, to heel it (another guess) about 8 or 10 degrees. If you don't have a touch of helm, rake the mast another hole and try again until you get it. If raked right, assuming good sails, the boat will point higher and go faster. The difference between poor and perfect is remarkable. Jerry ******************************* Date: 16 Jun 2000
Jerry, Is this how to set up a 17 also?
Yes, and a 23 also, and most other well-balanced boats, too. Jerry ******************************* My #361 has a distinct rake aft. Is that normal? My shrouds go to the after hole in the chain plates. (The former owner had lifting hooks in the forward holes which I removed as catching hazards for the jib sheets.) Is a lot of rake normal, or should I move the shrouds to the forward hole? John Butler