Bad weather is likely to delay the probe into the helicopter crash over the Morecambe Bay gas field until next week at the earliest, say coastguards.
Clockwise from top left: John Shaw, Alfred Neasham, Stephen Potton and Simon Foddering all died
Ged Lynch of HM Coastguard said the delay came as conditions were near gale force and that the weather was set to deteriorate further this weekend.
The search for a seventh man missing following the helicopter crash that killed six has now been called off.
A data recorder from the 20-year-old helicopter has not yet been recovered.
All the men involved in the crash off the Lancashire coast have now been named.
Rig workers Robert Warburton from Heysham, Leslie Ahmed from South Shields, John Shaw from Kirkcaldy and Alfred Neasham from Durham were killed.
Pilots Stephen Potton from Blackpool and Simon Foddering from Preston also died. A search for contractor Keith Smith has been called off.
The Maritime and Coastguard Agency said it had called off the search for Mr Smith, 57, of Stockton-on-Tees, because "all that could be done in terms of search and rescue has been done".
The helicopter, which took off from Blackpool Airport, was on a routine flight between rigs for gas firm Centrica when it crashed into the sea 25 miles off the coast on Wednesday evening.
The cause of the accident involving the Eurocopter is unknown
Lancashire Police said the helicopter, a Eurocopter AS365N, had flown to two gas rigs and was on its way to a third when it "veered to the left" and ditched into the sea.
It crashed 500 yards away from the third rig. No emergency call was received.
The helicopter was flying from the Millom West platform - owned by Burlington Resources Ltd but operated by Centrica - to the North Morecambe platform on its way to the South Morecambe platform, which is permanently occupied.
Three people on the third platform witnessed the incident. One of them had been due to board the helicopter and was described by police as "traumatised".
Police said the weather was normal for the time of year and that the witnesses said they saw nothing unusual with the helicopter.
The families and friends of crash victims have been paying tribute to their loved ones.
Mr Shaw's wife Deirdra said her 51-year-old husband - known to friends as Jake - would be "sorely missed by everyone who knew him".
Mr Neasham's daughter Jill said her family would "never come to terms with" the death of her father, Alfred, 57.
Neighbours of Mr Foddering, 33, described him as a "fantastic guy" and a "devoted father".
And relatives of 51-year-old Mr Potton, speaking from his home in Blackpool, said they were devastated.
Mr Ahmed, 48, had been planning to hold a late Christmas celebration with his family because he had been working over the holiday.
The family of Mr Warburton, 60, asked to be left alone to grieve in peace.
A Cleveland Police spokesman said friends and family of missing Mr Smith were "clinging to the hope that he will be found safe and well."
Frank Cygal, a gas rig worker turning up for work at Blackpool Airport helicopter terminal on Thursday, said: "It's just horrible thinking about the families.
"Those fellas coming home for New Year had not had a Christmas and the families - I can't imagine what they're going through."
David Learmount, safety expert with Flight International magazine, said the age of the helicopter - it was manufactured in 1986 - was "one of the factors that the investigators will look at.
"But, on the other hand, all of the other components are lifed individually."
He said: "Apart from the chassis, just about every part will have been replaced - in some cases several times - since it was built."
CHC Scotia said that, while the aircraft itself was 20 years old, "most of the components are regularly replaced".
Spokesman Keith Mullett said the firm operated five Eurocopter AS365N helicopters - known as the Dauphin - in Europe, and the aircraft's safety record and performance in the fleet had been "excellent".
He said: "The amount of information we have is extremely limited. The investigation is in its early stages.
"It is much too early to say or to speculate at all about what could have happened," he said.
Centrica's Sam Laidlaw said: "Our priority is to provide as much support as we can. Our thoughts and prayers are with the families at this terrible time."
Mr Laidlaw said it was the first major incident to affect the company's operations in Morecambe Bay since they began 21 years ago.
The four dead passengers all worked for Centrica, and Mr Smith is an employee of one of its contractors, Costain Petrofac.
The Air Accident Investigations Branch (AAIB) has launched an inquiry into the incident.
Gas was discovered in the area in 1974 and extraction operations began 11 years later. There are about 143 Centrica staff working on the platforms at any one time.