Oh yes, sunk some of my countrymen and even one or two Danes. but then I do sink ships on principle sometimes, since there are some significant bits of Dutch Geography missing on the map, and some added that weren't there at the time, I once spent a whole patrol in may 1940 sinking ships that couldn't have sailed from those areas
Call me nuts, but sometimes you gotta stick up for the principle, even if they're only fishing boats...
