AC45 in SF Bay (Capsize)

It was a fine day this past weekend as I set out on the water with the A-Class Catamaran to try and say hello to the big AC45 on the Bay. The gusts pushed upwards of 20 knts, confused chop from the tides rolled by and I quickly knew my place was not in the channel; I turned tail and had a wet ride back into the safety of flat water just outside the club.

Fortunately, video of the Oracle AC45s has been posted and shows the power of the big cats even with choppy seas. Their pair of boats are racing at high speed across the Bay until the leward bow of Coutts is caught by a wave and then…

Note that the crew are stuck to the windward aft hull like glue even though they’re hiking with just a strap over their feet at the 0:23 mark. I don’t see harnesses, only drysuits, lifejackets and helmets. Very different picture from the big comfortable pits with shorts and polo shirts of the old AC boats. Also note that as the rudders lose traction the crew has only a couple seconds to react — blow the jib and wing — before they’re over.

Update: At about the same time yesterday that I was commending Coutts and his team for saving the boat, he lost control, capsizing while bearing away and sending the trimmer through the wing.

For what it’s worth, bearing away is definintely one of the hardest moves on the catamaran. The pressure on the sail builds faster than the hulls want to move, forcing the helmsman and trimmers to navigate through an imminent tripping moment. The bear-away at windward marks is where most carnage happens in high-wind catamaran racing.

Key differences between the two incidents:

  • The water was only just to the forward beam and the boat was able to use its momentum to punch out of the water in the first video. The second video shows water far behind the beam — much deeper angle for the leward hull into the water — and the boat is almost entirely stopped.
  • The boat lost steerage as it was moving to windward in the first video. As soon as the leward aft hull touched the water it continued to track to windward and the sails could luff, dumping power aloft and bringing the windward hull down. The second video shows the rudders were turned hard downwind when steerage is lost — a reaction that stuffed the hulls hard into the waves instead of releasing pressure. There was no correction possible once the water flowed over the beam and pressure increased at the top of the mainsail.

If they keep sailing in these wind and sea-state conditions I may never get a chance to bring the A-Cat alongside. Perhaps the AC45 class should consider a max windspeed rule (e.g. 25knts).

At some point you have to wonder if it would be more fun to watch F1 cars try to race on smooth streets or on off-road rocky conditions. On the one hand it is great to see engineers try to work around the incredible risks of nature — build machines that can withstand anything — but on the other hand most high-speed endeavors use a controlled/planned environment to narrow their focus of investment.

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