> A sail rig will tend to "round up" if the balance of > the rig is predominantly aft of the center of > resistance. The result being, the bow will tend to > come up into the wind. At the risk of belaboring this point, I believe the above describes "weather helm" (versus "lee helm") whereas "round-up is a bit different and severe. As the boat heels due to wind pressure, the underbody profile changes because of the curvature of the hull. Just when the helmsman needs the rudder the most, it becomes increasingly inefficient as it departs from perpendicular, eventually stalling rendering it useless. Pressure is finally relieved when the boat either comes bow into the wind ("round-up," common), lays flat on her beam ("knock-down," uncommon), or something snaps and breaks (rare). Some old sailboats (gaff rigged "cat boats" for example - once popular in the Chesapeake) had unstayed masts that would flex to spill the wind, or break entirely if needed. The fisherman would fell a new tree and presto: new mast. Tom Wylie, one of the leading sailboat designers (and most innovative) still uses these principles, but with hi-tech, carbon fiber marconi wishbone rigs instead of a traditional boom (think windsurfer) creating extremely fast and easily handled boats. Peter www.SeaSkills.com