Here's the story, via Matthew Archbold at the National Catholic Register; as told by the late William F. Buckley, via David Niven:
"David Niven told the engrossing story (I had never heard it) of a single episode in the chaotic flight from France after Dunkirk in 1940.
One motley assembly, ‘Royal Air Force ground personnel who were trapped, Red Cross workers, women, ambulance drivers and, finally, the embassy staff from Paris with their children — by the time they got to St. Nazaire at the mouth of the Loire, there were over three thousand of them and the British government sent an old liner called the Lancastria to come and take them away, with three destroyers to guard her. They were just pulling up the anchor when three dive bombers came.
The destroyers did what they could, but one bomb hit, went down the funnel and blew a huge hole in the side, and she quickly took on a terrible list. In the hold there were several hundred soldiers. Now there was no way they could ever get out because of the list, and she was sinking. And along came my own favorite Good Samaritan, a Roman Catholic priest, a young man in Royal Air Force uniform. He got a rope and lowered himself into the hold to give encouragement and help to those hundreds of men in their last fateful hour.’
‘Knowing he couldn’t get out?’ ‘Knowing he could never get out, nor could they. The ship sank and all in that hold died. The remainder were picked up by the destroyers and came back to England to the regiment I was in, and we had to look after them, and many of them told me that they were giving up even then, in the oil and struggle, and the one thing that kept them going was the sound of the soldiers in the hold singing hymns.’”
Read the rest at the NCR, link above.
Just something to consider when people heap opprobrium on Catholic priests. Not that we are exempt from criticism, or that we don't often deserve it, but...