Google the “Altmark Incident” February 16 1940, not only did the Royal Navy board an enemy ship, they fought the Germans with cutlasses. This last detail tickled Churchill pink, he loved the idea that even in 1940 British sailors could still fight their way on to the deck of a ship swinging cutlasses. Buckling the old swash and all that, eh what?
I remember the Altmark Incident, or reading about it years ago now that you tickled my memory.