"The first day of racing in Cowes Week, Isle of Wight was disrupted on Saturday when the 124,000-ton Hanne Knutsen encountered a fleet of yachts.
One of the racing vessels, Atalanta, was in collision with the 870ft-long Norwegian-owned tanker as it proceeded to the oil refinery at Fawley, near Southampton. The yacht, which normally has nine crew members on board, became entangled in the larger vessel’s anchor and had its sails torn off and mast snapped." Read article
After viewing the video, I'm guessing they saw the tanker behind the sail, and the spinnaker collapsed as they tried to point higher to squeeze by. Bad miscalculation of speeds. That seems to be the only reasonable explanation for this accident that could have had a much more tragic outcome. It is a reminder to keep checking behind our sails and talking to the skipper. The "right of weight" rule applies here. - Ed.