London's High Court heard how it was "virtually impossible" that a man who went overboard from the deck of a Stena Line ferry ended up in the water accidentally.
The claim came in the midst of a widow's legal battle for compensation after her husband - a former Kilkenny County Council engineer, Mr Michael Davis (35) - died during a Stena Line crossing from Rosslare to Fishguard in October 2000.
Ms Marion Davis, Melrose Avenue, Yate, Bristol, is suing the ferry company for damages, claiming it was to blame for her husband's death after launching an abortive rescue attempt to "extract" him from the water.
Lawyers for Stena Line vigorously deny all liability.
Mr Simon Kverndal QC, for the widow, told Mr Justice Forbes that Mr Davis had gone overboard from the boat on October 29th, 2000. A short time later a sea rescue helicopter was scrambled to look for the missing man.
He was spotted about 40 minutes later by a crew member on a container ship and, when the weather was adjudged too bad to launch lifeboats from the ferry, it was manoeuvred close to him in an attempt to lift him from the freezing water.
However, Mr Davis was then submerged as the ferry came too close, counsel said, reappearing on the boat's other side, "face down in the water, obviously dead".
But Mr Michael Tillett QC, for the ferry company, told the court that Mr Davis, who had two children, had a history of depression. He added that he must have gone overboard as a result of as deliberate or reckless act rather than accidentally.
The hearing continues.