Guy Griffiths - How to spot a submarine
Radar only came in later on. That's when the tide turned in late '42, '43 in the North Atlantic and they could detect the periscopes or by radar but we still had to spot visually.
If the weather was good, you could spot them if they were close, which wasn't a good thing. It was a form of warfare which very nearly brought Britain to her knees, but they sailed through it. They had some tremendous captains in their escort forces in the Atlantic.
That's an ocean up there which is different to anywhere else in the world. Sort of rougher weather, cold, miserable. Real sailors up there.