A search for four Britons feared dead after the yacht they were sailing capsized in the mid-Atlantic Ocean has been called off.
The crew of the Cheeki Rafiki, a 40ft Beneteau performance racer/cruiser yacht, ran into difficulties some 1,000km (620 miles) east of Cape Cod in Massachusetts on Thursday while returning from the prestigious Antigua Sailing Week regatta.
Contact with Andrew Bridge, 21, James Male, 23, Steve Warren, 52, and Paul Goslin, 56, was lost in the early hours of Friday while they were diverting to the Azores.
US and Canadian aircraft and merchant vessels looked for them throughout Friday and Saturday but have now called off the search.
The men were sailing the Cheeki Rafiki back from Antigua for Southampton-based yacht training and charter company Stormforce Coaching when they went missing.
A US Coastguard spokesman said that two US and one Canadian aircraft had been assisted by three commercial vessels until the search was called off at 5am local time.
The spokesman said: "We searched with multiple assets over 4,000 square miles for pings from the vessel's personal locator beacons.
"After receiving no more transmissions we believe that we would have found them by now if we were going to find them.
"These beacons are small devices and the ones being used have a very short battery life."
One of the commercial vessels taking part in the search, the 1,000ft container MAERSK KURE ship, discovered debris thought to be the overturned hull of the Cheeki Rafiki but did not stop to inspect it because nobody was seen on board.
Weather conditions in the area where the men went missing were described as treacherous, with winds in excess of 50 knots, waves of 15 to 20 feet and visibility reduced to under a mile.
Mr Bridge, who is from Farnham in Surrey, was being paid by Stormforce for his role on the yacht, a spokeswoman for the firm said.
But Mr Goslin, from West Camel, Somerset, Mr Warren, from Bridgwater, also in Somerset, and Mr Male, from Southampton, were also described as "very experienced offshore yachtsmen".
Stormforce director Doug Innes said that the yacht had first started taking on water on Thursday but the skipper was in contact and the crew were keeping the situation stable.
He said that it was possible that the crew took to a life raft after contact was lost on Friday.
"Search and Rescue authorities were mobilised and a mixture of Canadian and US aircraft along with merchant vessels searched throughout Friday and Saturday," Mr Innes said.
"Although the search efforts co-ordinated by Boston were exceptional we are devastated that the search has now been called off so soon.
"Our thoughts are with the four yachtsmen and their families and we hope and pray for them all."
A Foreign Office spokeswoman said: "We are aware of a missing yacht off the East Coast of the USA with four British nationals on board.
"We are in continual contact with the US Coastguard and are providing consular assistance to the families."
Yachting experts expressed concern that the hull of the yacht had been found but not inspected.
Andrew Pindar, who runs the GAC Pindar racing team, said "The fear with yachts upside down is that people could be trapped inside them.
"The classic example is Tony Bullimore, who capsized in the Indian Ocean in the 1990s and was trapped for days on end, surviving on a pocket of air before he was rescued.
"I don't know what has happened in this particular case and wouldn't want to speculate, but if nobody has gone to look inside there is a clear worry that survivors could have still been trapped there.
"It is horrific to think that it (the container ship) could have sailed on with the possibility that someone was still inside.
"I would have hoped for them or somebody with the right facilities to possibly have lowered somebody down or used some other way of approaching the yacht and knocking on the bottom of the hull."
Mr Pindar added that, having seen a picture of the Cheeki Rafiki taken from the container ship, it appeared to be an upturned boat rather than mere debris.
"It looks like it was missing the keel and it is possible a bulb had fallen off the bottom," he said.
"I don't know this particular boat, but it is a possibility that there was some catastrophic failure of the keel in some form or another which would have caused the boat to tip over."
Petty Officer Rob Simpson, a spokesman for the US Coastguard, said: "The MAERSK KURE is a 1,000ft container ship which does not have the manoeuvrability, capacity and ability to help.
"It has a fairly limited possibility of picking anything up - i t is not designed for search and rescue capabilities or anything like that or trained to do anything like that."
Asked if others could have attended the scene where the hull was found, he said: "It is not possible to take a helicopter that far off shore - the search area is very far out in the middle of the Atlantic Ocean. The grand scale of this is immense.
"Aircraft take four or five hours to get there and vessels can take over a week. This particular ship just happened to be in the area, they were not tasked specifically for this."
PO Simpson said that two beacons used by the Cheeki Rafiki crew, which he described as "about the size of a mobile phone", give off GPS coordinates of their last known location while their batteries last.
But he added: "We are not actually able to hone into them when on location with an aircraft and have stopped receiving signals from them."
Mr Bridge's aunt, Georgina Bridge, said that her nephew was the captain on the yacht and was travelling back from taking part with the three other yachtsmen in the Antigua Week regatta.
She told Sky News: "Obviously the family are really concerned that the search has been suspended and we are really hoping that it will be resumed.
"We are holding out great hope that Andrew and the guys on board Cheeki Rafiki will be found.
"We are hopeful that they were able to launch a life raft and that they are still on board that, so we would just really like the search to be resumed."
Ms Bridge explained that all four men were "very experienced sailors", adding: "Andrew has been sailing since he was a small child, he has a real passion for sailing and has taken part in many races.
"He is a very experienced captain and has sailed Cheeki Rakifi a great deal. He has taken part in Fastnet and other very challenging races.
"Sailing is his passion and we just want him home."
Craig Burton, for the Royal Yachting Association, told Sky News the crew was "very, very experienced".
He said: "The skipper, Andy, has done numerous ocean crossings, he's a very experienced guy.
"We know they had water coming on board and were unable to find the source.
"When the search first started in the early hours of Friday it was very strong winds and some pretty high seas, so very challenging conditions for anybody on board."
He described the Cheeki Rafiki as a "very well-equipped" vessel.
The crew joked on social media about their lengthening beards and the food they were eating before running into trouble on their way back to Southampton.
A blog posted to Facebook on Tuesday, one of their last, read: "And yesterday we did it ... we turned east for home, completing our first 1,000 miles [which] was celebrated with a release of a cherished beach ball with a note inside, I hope it doesn't get home before us!
"We have had one stormy morning so far with beating rain and a force 5 wind which lasted a few hours, but we are still enjoying plenty of sunshine and warm temperatures.
"We are already thinking of home and the ones we love and miss, you know who you are!"