A man judging a North Sea dinghy race has died from what is thought to be a heart attack after a number of competing boats capsized in high winds.
More than 100 dinghies were taking part in a race
The man had been judging a Laser-class race off Hartlepool, Teesside, and was pronounced dead at the town's hospital.
Five lifeboats and a police helicopter helped rescue up to 30 competitors left clinging to hulls of capsized vessels.
Cleveland Police said the man's identity was not yet being released but he was from outside the area.
Mike Craddy, operations manager for Hartlepool RNLI, said more than 100 one-man dinghies had been in the Tees and Hartlepool bay, taking part in a qualifying event for the Laser World Championship.
High winds pushed boats up to five miles out to sea and spread them two miles along the coast, the RNLI said.
Redcar lifeboat station recorded winds up to force nine.
Mr Craddy said: "Some of the boats had retired by this time because of the worsening weather but there were still a lot of boats out there and it took them by surprise."
He added: "The operation went very well from our point of view."
Inshore and all-weather lifeboats were called out from Redcar, Hartlepool and Teesmouth at about 1230 BST.
All people involved had been accounted for by 1349 BST, with at least 20 sailors brought ashore, the coastguard said.
Mike Green, Humber Coastguard watch manager, said: "This was an awkward incident due to the number of Lasers involved.
"Race control are to be commended on the speed with which they requested assistance and for an excellent tally system which enabled all personnel to be quickly accounted for."
Mr Green added: "The Royal National Lifeboat Institution response to this incident was extremely rapid and efficient and they are now recovering any abandoned Lasers."