Centre of gravity high when wave hit B.C. whale-watching boat: TSB

A boat carrying 27 people capsized off the coast of Tofino, B.C., on Sunday, Oct. 25, 2015. (Daniel Frank)

TOFINO, B.C. -- Sightseeing passengers crowded the top deck of a whale-watching vessel when it was hit by a wave and then rolled, sending 27 people into the water off Vancouver Islands west coast, an investigator said.

On Tuesday, Marc-Andre Poisson, the director of marine investigations with the Transportation Safety Board, released preliminary results of Sunday's accident that claimed five lives. One passenger is still missing.

"We know that most passengers and crew were on the top deck on the port side ... this would have raised the centre of gravity, affecting the vessel's stability," he said during a news conference.

"We also know that the sea conditions were such that the wave approached the vessel from the starboard quarter," he said. "We know the vessel broached and then capsized."

All five people who died were British nationals. The missing man is from Australia.

Rupert Potter, the British consul general based in Vancouver, said earlier in the day the deaths are a tragedy that is resonating around the world.

"It has clearly deeply affected those involved," he said. "It's affected the community here in Tofino and it's affected people back in the U.K."

Potter shook hands with B.C. Premier Christy Clark and expressed his thanks for the support he and the victims' families have been receiving.

Potter said while he has been in Tofino he has met with the relatives of those who died.

"Our focus is of course the families who have been affected and to provide whatever support we can to help them through this process," he said. "The bravery and courage they have shown through what is a difficult time, I find deeply moving."

Clark said she was horrified and heartbroken when she heard about the capsized boat but she's proud of the way British Columbians came together to help.

"The Ahousaht First Nation, the people of Tofino, the people who know this coast so well, when there was a crisis, when there were lives at risk, people stepped up and stepped in and saved lives," Clark said, as she thanked the community.

The BC Coroners Service has identified all five of the victims, including David Thomas, 50, and his 18 year-old son Stephen, who were visiting from the U.K.

The family's church released a statement Tuesday.

"It is with great sadness that we have to report the death of two active members of the Gateway community," said Gateway Church Swindon in Wiltshire, U.K.

The church said Thomas's wife, Julie, was rescued and is in hospital with minor injuries.

Thomas was a managing architect with Microsoft United Kingdom. Michael Van der Bel, head of Microsoft U.K., said in a statement that the company is shocked and saddened by the deaths.

"Our thoughts and deepest sympathies are with their family, friends and David's colleagues and we will be doing everything we can to support them."

Britain's Telegraph newspaper said Stephen Thomas, who had Down syndrome, died two weeks shy of his 19th birthday.

The teen was a talented photographer who won a national competition last year for a photo he took in Alberta's Banff National Park, said Carol Boys, CEO of the Down's Syndrome Association in Britain.

Another victim was Jack Slater, 76, a British national living in Toronto.

His daughter, Michele Slater Brown of Milton, Ont., posted a message on Facebook saying she was notified about her father's death "in the wee hours this morning," and called him "larger than life, a charmer, handsome, entrepreneur, engineer in the navy ... and a lovely dad."

Katie Taylor, a 29-year-old Briton living in Whistler, B.C., and 63-year-old Nigel Hooker of Southampton, England, also died when the Leviathan II sank.

An initial investigation suggests the passengers were not wearing life-jackets, said coroner Matt Brown.

"In terms of regulations, as I understand, (wearing life-jackets) is not required on this kind of vessel," Brown said. "Will that be part of an ongoing investigation? I'm certain it will be and it will be part of the interviews and investigation to follow."

Poisson said TSB investigators will try to recover the electronics on the vessel on Wednesday in an effort to help further the investigation.