Some fun info for you all about Dunkirk that was not mentioned in the movie. I will not give anything away so dont worry.
The old yachtsman was Second officer Lightoller of Titanic. I know this for sure because I was personal friends with Walter Lord who wrote the book about Dunkirk... and the Titanic.... The yacht looks a like Lightoller's yacht sundowner and he lost his son in the opening days of the war and he taught his dad how to evade a strafing run... This is detailed in the book.
Hope you enjoyed the worthless info.
Todd