The America’s Cup

There’s a competition going on in San Francisco to decide the winner of the America’s Cup. Those people who do not have an interest in yachting may not have heard of it, but it is the Superbowl of the yachting world. Currently it is being fought out between Oracle Team USA and Emirates Team New Zealand. The New Zealand team currently lead 6 wins to 1. [Update: The score is now 6 – 2.]

For spectators on the shore yacht racing normally happens a long way off and with few visual clues as to what is happening and it is often next to impossible to tell who is leading and even who won the race. The yachts are visible as small white dots although the deployment of a spinnaker will swell the dots and may introduce a bit of colour, but the to-ing and fro-ing of the yachts is still difficult to decipher.

The America’s Cup is different in that technology has come to the spectators’ assistance. A view can be shown on television of the yachts as seen from a helicopter or motorboat shadowing the yachts, but it will still not be obvious who is leading, since when going upwind the yachts travel at a significant angle to their target course. At each side of the course the yachts must change direction, a procedure known as a ‘tack’. If both yachts are travelling on parallel courses it is possible for the trailing boat to appear to be leading.

So to help spectators the live view is overlaid with graphics which show each yacht’s distance from the mark (the target for this leg) or from the finish line if the leg is the last one. The graphics also show the boundaries of the course if the yachts are approaching them. The distance between the lines for the two yachts shown who is in the lead and by how much.

The graphics also show the yacht speeds though I’m not sure if that is the speed towards the mark or finish line or merely the straight line speed. Another thing that the graphics can show is any ‘bad air’ that the leading yacht is casting over the trailing yacht. The leading yacht’s sail disturbs the the air as it flows over it, and this disturbed air is less efficient at providing the trailing yacht with energy and so it tends to travel a little slower. The leading yacht is said to cover the trailing yacht and the trailing yacht will endeavour to escape the cover.

The most interesting times in a yacht race are when the vessels are rounding a mark. The graphics for this are a circle round the mark and a series of dots or blobs representing the yacht’s course, as if the yacht were dropping a bucket of dye every second. There is also a countdown clock indicating the number of seconds that one yacht is behind the other.

So there’s plenty of information about the races and it makes for fascinating viewing. (There are some people who still don’t get it and who watch it for 5 minute or so and then go and do something else, but then again, Formula 1 leaves me yawning). The course in San Francisco is very close to the shore and this does allow spectators a good view of the yachts, though I suspect that most of them will be keeping up to date via cellphones. There’s an app for it!

[Update: I just watched latest race. Oracle Team USA won this after a near capsize by Emirates Team New Zealand.]

The class of yacht being used in the America’s Cup in San Francisco is designated as AC72. These are huge catamarans (dual-hulled yachts) with fixed sails and full of the latest technology, computers and hydraulics. A failed battery cost Emirates Team New Zealand one race!

The yachts are spectacular in action as they rise up out of the water on hydrofoils, which reduces hull drag to nothing and allows the yachts to reach speeds of up to 50mph (44 knots). This does not come without its dangers and several of the yachts have dipped their bows into the water leading to at least two incidents where yachts have “pole-pitched” and tipped over in one case killing one of the crew. In both cases the yachts were severely damaged. Emirates Team New Zealand dropped their bows into the water in one case  but appeared in no danger of flipping over. Oracle Team USA were one of the teams whose yacht was almost destroyed  in an incident.

The yachts are filled with technology and are very technical to race, apparently, and have proved very popular in San Francisco with huge crowds turning out to watch action. Millions more are of course glued to their TV screens and cellphones. And this, below, is what it is all about.