In the April issue ("Control the Cross," p.60), we covered controlling the boat-on-boat upwind cross with anticipation and good planning. When there's a group of tightly clustered boats on port approaching a starboard-tack boat, the leeward-most port-tack boat must choose its language carefully. This means giving the boat immediately to windward a "heads up" call well out from a starboard-tack opponent (maybe as much as 20 seconds ahead of time). The windward boat may not be able to see the starboard-tack boat, and that's why there is a mandatory call in Rule 20.1 ("Hailing and Responding"). The leeward boat can ask for "room to tack," and the windward boat must either tack or respond with "you tack," at which point they must keep clear. The leeward boat, by hailing for room to tack, is then required to tack and keep clear of starboard. If the leeward boat delays in alerting the windward boat, they risk having the windward boat become a major obstacle. Remember, the back and forth of the mandatory hails can take a good 5 to 7 seconds to complete. If the windward boat hasn't been given fair warning and isn't ready to tack, they may end up fouling the leeward, which means neither team is sailing as effectively as possible. With anticipation, however, a quick shout over the shoulder 30 seconds out from the potential incident will help tremendously: "Hey, we've got a starboard-tack boat coming. I'm probably going to want to tack." Then the windward boat can effectively prepare to respond, and because the language was clear, leeward is not yet obligated to take any action. Likewise, the windward boat is more likely to tack quicker when you ask for "room to tack," increasing that small buffer to leeward after you put a tight leebow on the starboard tacker.