When umpiring the most difficult part of the "job" is to be in a position where you can see what the rule infringement is. To be at the right place at the right moment. This involves anticipation of what the sailors will do, quick reactions and skill with the rubber boat. But even if you can do all these things perfectly, it is impossible to be at the right place all the time. Simply because sometimes you need to be at two places at once. This is where the wing comes in. In the wing a driver and a designated umpire communicate to the match umpires by arm signals or by radio, relevant information. They are the second set of eyes the umpires need to get a three-dimensional picture.
Positioning of the wing boat is - as with the umpire boat - the key to successful 'winging'. Generally speaking the wing boat needs to be at a right angle from the boats related to the position of the umpire boat. When the latter is behind to look at the distance between the boats, the wing is beside the boats to look for the overlap. When boats cross, the umpire boat is with the port tack boat, and the wing with the starboard tacker.
First of all they signal if there is, or there is not, an overlap between boats. If by radio they use: "Clear" or "Overlap", usually with a distance added: "Clear half a boat length" or "Clear one meter". When signaling overlap they also add a distance; "Overlap bow to bow" indicating boats are next to each other with bows at the same 'hight', or "Overlap, 2 meters". By adding the distances to the information, umpires can quickly understand if an overlap is going to be broken or established.
Match racing starts at the four minute signal, when boats enter. The first encounter is usually a port and starboard encounter. Unless one of the boats is late or otherwise not able to go at four minutes, the Yellow boat on starboard tack will try to "go" for the Blue boat on port tack. The wing boat starting position is to windward off the starting vessel or committee mark at a right angle to the starting line to check early entry of the Yellow boat. Once that has been done the wing has to give information to the umpires about the direction Yellow is pointing. To do that, the wing motors to a position behind/besides the Yellow boat, so that his line of vision goes trough the helmsman of the Yellow boat looking at Blue. That way the wing can tell if Yellow is 'aiming' at Blue or steering a course above or below.
Once Yellow steers a course at Blue, the latter has an obligation to keep clear and is obliged to take action. If Yellow is aiming at Blue and holding it's course while Blue does nothing, and at the end is forced to avoid the Blue boat, they have not kept clear and when a call is made, will be penalized. If Yellow is not aiming at Blue she's keeping clear and does not have to take action. Even when Yellow is aiming at Blue from some distance and Blue is changing course but Yellow follows - keeps aiming - Blue has no protection from RRS 15, only from RRS 16.1. In short, at the first entry the most important information the wing can give is the course of Yellow relative to Blue.
When boats end this first encounter in a 'dail-up' the wing boat is beside them relaying information about the overlap. Because of the low speed and the proximity of the umpire boat, this is however not the most important piece of information. It is the speed of the boats through the water, specially if they go backward. That is something the wing can see from its position much easier than the umpires. When sails are backed it is sometimes crucial to know if a boat has begun moving backward to determine right of way.
Next time in "Winging it" part 2: The rest of the prestart, the beat and the windward mark.