The search for four British sailors missing in the Atlantic has resumed after it was called off on Sunday.
Ministers said the US Coast Guard had agreed to continue searching after a request from the UK government.
The 40ft Cheeki Rafiki was sailing back to the UK from a regatta in Antigua when it got into difficulties.
The wife of one of the men said it had been an "emotional rollercoaster" since all contact with the crew was lost on Friday.
Cressida Goslin - wife of Paul - and other members of the men's families met with Foreign Office Minister Hugh Robertson on Tuesday afternoon before leaving for the US Embassy.
The four missing crew members are Mr Goslin, 56, from West Camel, Somerset; Andrew Bridge, 22, from Farnham, Surrey, the yacht's skipper; Steve Warren, 52, also from Somerset, and 23-year-old James Male, from Southampton.
The US Coast Guard, which on Monday said the search would only be resumed if "new developments about the case" emerged, said it had agreed to deploy rescuers at the request of the UK Foreign Office.
Mr Robertson said on Tuesday afternoon the Foreign Office had been "impressing on them the need to continue the search" since the weekend.
"They're human beings and they absolutely understand what is going through the minds of the families and the relatives of all those affected," the minister said after meeting men's families.
The coastguard's chief of media relations Carlos Diaz told the BBC: "There's no frustration about the search - our guys followed the procedures they had to follow at that time."
The US rescuers issued a video of one its aircraft leaving North Carolina for Boston on Tuesday.
Speaking outside the Foreign Office after what he described as a "very positive meeting", Graham Male - father of missing James - thanked the UK, Canadian and US authorities and urged people to continue signing an online petition which has attracted more than 200,000 signatures.
"Let's bring our loved ones home," he told waiting reporters.
The racing yacht began taking on water 620 miles (1,000km) east of Cape Cod in Massachusetts and diverted to the Azores on Thursday.
Missing Mr Warren's son-in-law, Dan Carpenter, said: "We are holding out hope. We are aware that it is still a long shot but while there is some hope, we are concentrating on that."
'You never know'
The Americans had said the estimated survival time past the time of distress was approximately 20 hours and that their crews had searched for 53 hours.
But the decision to resume searching came after family members insisted they could still be alive in the yacht's 12-man life raft.
Twelve-person life raft
A raft, such as that on board the Cheeki Rafiki, is required to meet the international standard ISO 9650, which stipulates how the craft must be constructed and what it must have on board. The rafts are highly visible and buoyant and can be boarded quickly in an emergency.
Skipper Mr Bridge's grandmother Valerie said: "We are delighted. It is at least something and that is all we were asking for, all we wanted was another search.
"It might not come to anything but people want them to do it and they are trying. It seemed too quick, just two days and we were saying 'if only they could do it for a bit longer'. You never know what could happen."
Mr Goslin's daughter Claire, who on Monday made an emotional plea to the Americans, said she was "over the moon".
"I just hope and pray with all my heart that now they find them."
Mrs Goslin, his wife, added: "It's been a complete emotional rollercoaster.
"The US wouldn't budge and then we thought they would, and then they wouldn't."
Tracy Edwards, who skippered the first all-women crew around the world, said the men had been failed by the coastguard.
"I'm absolutely delighted they've resumed the search, appalled that it's taken the British public to force the prime minister to do something," she told BBC News.
The US Coast Guard said locator beacons activated by the crew indicated they were in a position 1,000 miles east of Massachusetts on Friday morning.
The yacht was facing 15ft waves, 50mph winds and sea and air temperatures of 15C (60F), the US Coast Guard added.
A spokesman said over the weekend it had "saturated the area" in a two-day search of 4,146 square miles, involving three US and Canadian aircraft and three merchant vessels and "we would have found them" if it had been possible.
'Fly to the hull'
On Saturday, a cargo vessel which was helping with the search spotted and photographed an overturned hull which matched the description of the Cheeki Rafiki.
Nicola Evans, a friend of Cheeki Rafiki's skipper Mr Bridge, said: "When we started this campaign, we didn't know who would listen, just that our boys were lost at sea and we refused to let go of hope."
But his sister Kay Coombes said: "It's a shame that it has taken this long for them to change their mind and go back out there.
"I feel that we may have wasted a couple of days."
Sir Ben Ainslie, the four-time Olympic yachting champion, said: "If there is a chance they are still out there, then we need to keep looking for them."
And Sir Richard Branson, who also backed the online petition, urged any vessels in the area to aid the mission.
"I would urge any local ships or merchant ships crossing the Atlantic, and boats returning from the Caribbean to Europe, to divert through the area and join the search party.
"As well as the need to conduct a private search on water, I believe that the coastguard now needs to fly to the capsized hull to determine whether or not the raft is still there."