A US Navy warship helicopter spotted a missing yacht in the Atlantic but found no trace of its four-man British crew now feared dead, officials said Friday.

The US Coast Guard called off its search for survivors of the Cheeki Rafiki, a yacht crewed by four experienced British sailors that was returning to the UK after a regatta in the Caribbean, at 0200 GMT Saturday.

The boat's overturned hull was located 1,000 nautical miles (1,850 kilometers) east of Cape Cod on the northeast coast of the US.

Inside, search crews located the life raft secured in its storage space, "indicating it was not used for emergency purposes," the Coast Guard said in further indication the crew did not make it out alive.

The information was shared with the crewmen's families.

The 40-foot (12-meter) yacht was returning from a regatta off the Caribbean island of Antigua when it began taking on water May 16, about 600 miles east of Cape Cod. It lost contact a day later.

Coast Guard officials earlier gave the date of May 15, but later corrected it to the 16th.

The crew comprised of experienced captain Andrew Bridge, 22, and crew members James Male, 23, Steve Warren, 52, and Paul Goslin, 56.

"Navy crews observed that the sailing vessel's keel was broken off, causing a breech in the hull," the US Coast Guard said in a statement.

A surface swimmer "determined the boat's cabin was flooded and windows were shattered, contributing to the complete flooding inside," it added.

"The swimmer also knocked on the hull and reached an arm's length below the waterline with no results."

The Coast Guard said that it does not usually attempt to salvage vessels after a shipwreck.

"Based on the extreme sea conditions at the time of distress, but assuming best-case emergency equipment, the estimated survival time past the time of distress was approximately 20 hours," the Coast Guard said.

"Searches were suspended nearly 200 hours after the time of distress."

Captain Anthony Popiel, 1st US Coast Guard District Chief of Response, offered prayers for the missing men.

"It is with sincere compassion for the families of these four men that our thoughts and prayers are with them all during this difficult time," said Popiel.

"It is only after our deepest consideration that we suspend our active search efforts."

Popiel thanked the US Navy and Air Force for its help, along with the British and Canadian militaries for their assistance.

In a statement issued through the Foreign Office in London, Warren's family voiced their sadness at the news.

"We are very sad that the US has now suspended the search for Stephen and his friends," they said.

"From the beginning we, together with the other families involved, have continued to hold out hope that he would be found alive. The US Coast Guard have led an exceptional search.

"This is now an incredibly difficult time for all the family."