History / World War I:Naval warfare / Submarines (U-boats / U-boots).The crew of the German merchant submarine (U-boat / U-Boot) "Deutschland" (SM U 155; commissioned 1916) greeting a Weser steam ship. Captain Paul K鰊ig standing on the bridge.(Until 1917; merchant submarines were used to trade with the USA during the British sea blockade).Photo; c. 1916.Berlin; Sammlung Archiv f黵 Kunst und Geschichte.