British Sailing's performance director John Derbyshire has led the tributes to Olympic gold medallist Andrew Simpson, who has died in a training accident.
Simpson, 36, won gold in the Star class with Iain Percy at the 2008 Olympics and silver at last year's Games.
Known as Bart, he died when the catamaran he was aboard capsized during training for the America's Cup in San Francisco Bay.
Derbyshire said: 'Bart was one of the top sailors. He was a really nice guy.'
'It's a really big shock, totally unexpected. These are big powerful boats but you don't associate them with fatalities. It's very sad.'
Simpson was one of an 11-man crew on board the catamaran. He was trapped underneath when it capsized and did not respond to efforts to revive him using CPR.
The Surrey-born sailor was preparing for this year's America's Cup, the oldest trophy in sport, with Swedish team Artemis Racing.
America's Cup chief executive Stephen Barclay says he will wait for the full details of the accident before deciding whether changes should be made to the race, which has an opening ceremony on 4 July.
Barclay told BBC Radio 5 live: 'We'll review the circumstances and find out the facts and if changes are needed we'll make them but we can't judge that now.
'Boats follow these vessels with divers and doctors and the like on board in case these things h.