Relatives of 36 men who died in a mysterious trawler sinking hope their questions will be answered by a new expedition to discover the cause.

A North Sea diving vessel is leaving Aberdeen to investigate the wreck of the Hull-registered Gaul 80 miles off Norway.

Claims by families of those who died that the trawler was lost while spying on the Soviet Navy have been vehemently denied.

The Seis Ranger has been commissioned by the Department of Transport to carry out an underwater survey of the Gaul as part of the re-opened inquiry into the sinking in February 1974.

I do not think for one minute that she was fishing or she went down in heavy weather

Beryl Betts Relatives' spokeswoman

The wreck was discovered in August 1997 by an expedition funded by UK and Norwegian television firms.

A mission the following year failed to find any trace of the lost crew.

A manned dive from the Seis Ranger has been ruled out on safety grounds, so the search will involve remotely operated vehicles.

A remote camera will descend on the wreck

They will sweep the area for any remains of the crew or evidence relating to the spying allegations, as well as seeking a way to examine the inside of the vessel.

Beryl Betts, from Kingston-Upon-Hull, whose brother Billy Jones was on the trawler, said: "This time they are going to be on the site for 15 days, working 24 hours a day.

"Surely they are going to find out the truth this time.

Search for truth

"I do not think for one minute that she was fishing or she went down in heavy weather.

"I think quite a lot of the relatives believe that as well.

"This has gone on for 28 years and we want to discover the truth and find out if there any remains of our loved ones on board."

Deputy Prime Minister John Prescott last year ordered that the original 1974 inquiry be re-opened after relatives insisted the findings were flawed.