A beginners guide to the basic rules and tactics of Louis Vuitton Cup matchracing.

The two boats enter from opposite ends of the start line with five minutes till the start. The boat with the yellow flag flying off its stern enters from the committee boat end of the line on starboard and the boat flying the blue flag enters from the pin end on port.

Typically the two yachts then perform a manoeuvre known as the dial-up, which involves both boats going head to wind and sitting side-by-side. When in this position, with their sails flapping on neither tack, the boat sitting to port (to the left) must keep clear.

Quite often the boats have to sail backwards out of this position. To enable this the crew backwind the jib (sheet the foresail onto the opposite side), which pushes the bow of the boat around.

Another pre-start tactic is to get on the stern of your opponent and either chase them far away from the start box or over the line early. Although the boat that is clear ahead has right of way if the other boat trails close enough they are in a stronger tactical position with the ability to prevent the front boat from tacking or gybing.

As the seconds count down another tactic is to luff your opponent up over the line. If the two boats are on the same tack and overlapped the windward boat must keep clear of the leeward boat. As the leeward boat you are able to head up towards the wind and the windward boat must keep clear. However, the leeward boat must give the other boat time to get out of the way. If a protest occurs the on-the-water umpires decide whether enough room to move was given.

Once the race begins the leading yacht will head to the favoured side of the course. If the wind is shifting to the left, the left hand side of the course is favoured and vice versa. But quite often if the wind is even (coming directly down the beat) the leading boat will head out to the right hand side of the course to protect the starboard advantage.

This is because the boat on starboard has right of way over a boat on port, so when the two boats cross for the first time up the beat the boat on port must either dip behind or tack if they cannot cross clear ahead of their starboard opponent.

The basic idea on an upwind leg is for the leading boat to cover the trailing boat, always staying between them and the breeze. Quite often the yachts will engage in a tacking duel. This is when the trailing boat tacks out from under the cover of the leading boat and the leading boat tacks to cover.

Sailors can get tricky here performing what is termed a dummy-tack, which involves pretending to tack so that your opposition tacks, leaving you able to get fresh air.

The lead boat might also try to bounce the other yacht out to one of the laylines because once they are on the layline they run out of options and must simply follow the leader to the mark.

Buoys can also be a good place to use tactics. If the trailing boat can get an inside overlap before an imaginary two-boat length circle around the mark, they have buoy room, and the leading boat must allow them room to go around the mark on the inside.

Downwind, the trailing boat will try to sit directly behind the leading boat, blanketing them and casting foul air onto their sails, allowing them to catch up. The trailing boat can disturb the air up to 12 boat lengths ahead.

Actually passing a boat downwind is tactically quite tricky as the leading boat can use the rules to stop them, by luffing them up, or if the trailing boat gets too close and actually crashes into the boat ahead they will get penalised.
In America's Cup racing the boats are given a delayed penalty of 270 degrees, this means either tacking on a downwind run or gybing on an upwind leg. The crews are able to take the penalty any time after the start and before finishing. If both competing yachts incur penalties they cancel each other out and if a yacht gets more than two penalties they will be disqualified from the race.