First part on Winging can be found here.
During the rest of the pre-start the wing boat has limited possibilities to be of use. Generally the boats move so fast, circling and changing course, that it is impossible to be always in the right position. The best a Wing can do, is to be in position for a couple of crucial calls. That is if they have enough insight to anticipate where boats are going. The Wing stays to windward of the boats and will try to disturb the water as little as possible. They do call when a boat gybes, at the moment the boom passes midships with "boom" and when the mainsail is filled with "complete". And of course the overlap or clear, if they are in a good enough position to see.
In the final minute when boats will sail back to the starting line, the Wing takes a position to leeward of the boats to call the overlap. Mainly to inform the umpires of a possible hook-up, near the starting line.
If the wing doesn't peel off to do the entry and pre-start of the next match and stays with the starting boats, it will take a position to the right of the umpire boat following the boat on the right side of the course. In the beat the wing will always stay to the right, switching boats if they cross. This is because they give information to the umpires about the Starboard tack boat when approaching a Port tack boat.
There are two possible crossings that need input:
The first is when there's a collision course between Port and Starboard or Port crosses just astern. Because the Umpires follow the Port tack boat to leeward and slightly behind, they are not in an ideal position to see if the Starboard tack boat does or does not change course. Port is keep clear boat and must respond to the pending collision. But if the Starboard tack boat changes course, rule 16.1 is applicable and Port has must be given room to keep clear. So the Wing gives information on Starboards course by telling the umpires if they are "holding" or changing course "up" or "down".
Additionally the Wing is then also in the right position to see - in case of a slam dunk - the precise moment the overlap begins. Important for the umpires to determine of rule 17 is on or off.
The second crossing is when Port is likely to cross in front of Starboard. If it's close, Port might decide to tack at the last moment. Again with the wing behind the Starboard tack boat they call on the radio the precise moment they see the bow of Starboard pointing at the bow of Port. Usually preceded by "Stand by for Bow to Bow" then "Bow to Bow"...."Now". By calling bow to bow, the umpires can judge the distance between the boats at that precise moment and determine if Port will likely cross or not. If the distance is one boat length or less, Port cannot cross without breaking RRS 10 and is then not keeping clear. If the distance is greater than one boat length, they might get away with it. Possible to tack windward of Starboard.
If boats are far apart the Umpire will usually stay with the trailing boat. In match racing however, the penalty for touching a mark is Umpire initiated. The wing therefore follows the leading boat and stays close when that boat rounds. If there's an infringement of RRS 31.1 they signal the Umpire boat, who then can give the penalty. Additionally they can inform the Umpires - if the leading boat has an outstanding penalty - when that penalty is taken.
Next time in "Winging it" part 3: The run, the leeward mark and the finish.