Windward Stay Lost
When losing a shroud, especially one to windward, a standard safety approach (unless the mast has already gone by the board) is to immediately slack both main and jib sheets and turn head to wind. While in irons, drop all sails and jury rig something to stabilize the mast. A spare halyard made fast to a midship cleat or toe-rail usually will supply sufficient tension and support to permit time for a detailed assessment of damage. Once stabilized, or repaired if possible, one may try making shortened sail or, better yet, use the engine and return to port.If the mast is overboard, and it cannot be brought back aboard safely (almost impossible in boats over 24 feet in length), it may cause severe damage to the hull in a heavy seaway. To avoid such damage, securely fasten a spare anchor and rode to the mast, use your anchor buoy to identify it's location, hit the MOB key on your GPS to record its position, report (PAN PAN) the event to warn other mariners, and cut it adrift. It will no doubt sink but you can make arrangements to come back for it later.