Contact was lost last Friday 16 May with Paul Goslin, Steve Warren, James Male and skipper Andrew Bridge of the Cheeky Rafiki a day after the 40ft yacht got into difficulties when returning to the UK from a regatta in Antigua.
Two days later, a major search operation covering 4,000 square miles of the Atlantic was suspended with no sign of the yacht's crew.
It's not been confirmed what specifically prompted the search for the four men to resume - but the move comes a day after an online petition calling on US authorities to restart the search collected more than 200,000 signatures.
The families of the missing sailors maintain their insistence that the men may well have survived the rough ocean conditions in their liferaft, despite the US Coast Guard estimating a survival time of just 20 hours.
Veteran ocean-crossers Sir Richard Branson and Tony Bullimore have also backed the families' belief that the conditions were potentially survivable.
However, experts suggest it "highly unlikely" that rescue teams missed sighting any liferaft during last weekend's search.
A sighting of what's thought to be the upturned hill of the Cheeky Rafiki by the cargo ship Maersk Kure midway between Cape Cod and the Azores has yet to be confirmed.
BBC News has more on the story HERE.