How to execute: As Al turns head-to-wind to tack in position 2, Cy sails above close-hauled and heels to windward. Once Al passes head-to-wind, at position 3, he must keep clear of Cy. Essentially, Cy takes away Al's room to complete his tack. Al will likely (a) foul, (b) execute a bad tack, where he can no longer control Cy, or (c) realize that he won't be able to complete the tack and go back to starboard after two downspeed maneuvers. In almost all of the cases, Cy exits by putting his bow down and extending on port, now able to come back at Al later with starboard advantage. If you're in Al's position, anticipate that an opponent will do this to you; consider leebowing to maintain starboard advantage.