The sons of a woman missing and presumed drowned from a ferry accident last March near Prince Rupert, B.C., are asking the courts to have her declared dead so they can collect survivor benefits.

Shirley Rosette and her partner, Gerald Foisy, both in their 40s, were the only two of 101 passengers unaccounted for after the Queen of the North hit Gil Island and began to sink.

Her teen sons, Brandon and Brent, can't collect benefits through the Canadian Pension Plan until a death certificate is issued. Any eligible benefits through her employer also require a death certificate.

The petition would require the RCMP to detail the search effort for the missing couple.

"I can't just go in [to court] and say, 'They are deceased,' " said William Sokoloff, their lawyer.

Both the brothers and Foisy's two daughters have also filed lawsuits suing B.C. Ferries for damages.

A class-action lawsuit, which alleges recklessness and gross negligence on the part of the ferry's crew, goes to a certification hearing in B.C. Supreme Court in May.

It has been revealed since the incident that two members of the crew had trouble with the global positioning system display and shut it off before the crash. As well, logbooks that could have shed light on the grounding have gone missing.

with files from the Canadian Press