Just read the book by Christian Prag, the story of U604. just of interest. The laughing sawfish emblem(9th u boat flottilla) came about when a crewman saw a cartoon in a magazine drawn by the cartoonist Kossatz,and was adopted originally in green, rather than black, which later became popular. Notes 1 All U boats sailing from Kiel ,were not permitted to sail direct to the French ports, but had to go round the North coast of Scotland,2 Crews had no further training after work up, even when the Subs got more technically advanced, Metox etc. WHY?? The Grossadmiral admitted after the war that they only expected that the boats would survive 3 patrols.