Reducing weather helm...

Posted By: Mark N, Nimble Arctic, Jax FL
Date: 5/3/07 8:08p.m.

Report: outside forum guidelines

In Response To: Weather helm (Michael)

My experience with the Arctic indicates that you should be able to sail with a reefed main in 20 kts of wind with only light weather helm. The flat Nimble bottom provides a great deal of form stability. This coupled with the boat's weight and low aspect rig means that the boat heels very little when the winds pipe up. Because of the boat’s ability to stay on her feet, weather helm and not heel angle is the main indication that the boat is overpowered. For that reason, my reefing methodology is aimed entirely at reducing helm forces. As the wind starts increasing, I first start "blading out" all of the sails by tensioning the halyard, outhaul and boom vang. I can also sneak the genny blocks aft a little to help depower the top of the genny. I generally first stow the mizzen at around 15 kts. Even though this is such a small sail, its position so far aft generates a lot of weather helm. Next, I generally take a reef in the main ~20 kts. If the wind increases more, I start roller reefing the 135% genny as needed. In higher winds, I have found that sailing with the full genny and mizzen (no main sail) to be quite comfortable and balanced. Like most boats that I have sailed, reefing the Arctic when it is overpowered does not really hurt boat speed. As for the rudderboard, I find it very usefull but having never had one before, it took me a while to learn how to best use it. The bottom line is that I only use it in three cases: 1. When sailing in light winds (boat speed <2 kts) - it makes the boat easier to tack and gives the autopilot better control. 2. When docking - it gives much better control in tight quaters and helps the boat resist getting blow around by the wind. For the same reason, I also put the centerboard down while docking. If depth is an issue, I will put them down only half way. I have marked both control lines so that I know where halfway is. 3. When motoring for an extended period - it greatly reduces the helm force created by the propwash swirling aft from the propeller (on airplanes, this is called P-factor). Lowering the board reduces this force because it puts rudder into the "clean" water below the propeller. Use of the rudderboard while sailing in high winds probably made the weather helm worse. I have found that all things equal, the helm forces are less with the board up. Secondly, with your board only 3/4 down, all of that added rudder area is farther aft of the pivot point than it should be. If the board were all the way down, this area whould be closer to the pivot point and the forces would be less. When fully deployed, the leading edge of my board is vertical. The board easily freefalls into the full down position in all cases except when motoring at high throttle. In that case, I just have to throttle down for a second, then can throttle back up. If you have tried all of this and still have weather helm, you can try movin the rig forward a little (loosen backstay, tighten forestay) if you do not have a tabernacle. Lastly, you can try raising the centerboard just a little. This will move the "center" of the keel aft a little and will reduce the weather helm a little. Hope that this helps.