Ok , that explains why I got a grey icon after sinking a ship in convoy as I was already under when it sank. The second attack I made on the convoy the ship sunk didn't even show up. As long as I got credit I didn't care...I was more happy that for the first time I was able to make an attack on convoys and sneak away without getting a pounding ...than again it was in 1940
EDIT: I should have said first successful
night surface attack...what a difference absence of enemy radar can make.