The "Luftwaffe" had a few anti-shipping naval units such as 4.(St)/TrGr 186 to deal with Polish naval forces. This unit performed effectively, sinking the 1540-ton destroyer "Wicher" and the minelayer "Gryf" of the Polish Navy (both moored in a harbour). The torpedo boat "Mazur" (412 tons) was sunk at Oksywie; the gunboat "General Haller" (441 tons) was sunk in Hel Harbour on 6 September—during the Battle of Hel—along with the minesweeper "Mewa" (183 tons) and its sister ships "Czapla" and "Jaskolka" with several auxiliaries. The Polish naval units trapped in the Baltic were destroyed by Ju 87 operations. Once again, enemy air opposition was light, and the "Stukawaffe" (Stuka force) lost 31 aircraft during the campaign.