16. The Germans suspended the U-Boat campaign after sinking another liner
Following the international reaction to the sinking of a passenger liner, which the British propaganda machinery managed skillfully, the Germans suspended the U-Boat war, though not until after several more ships were sunk that summer. Since British vessels could fly the flags of neutral countries at will, their vessels were effectively shielded. The Germans also announced that passenger liners would not be attacked under any flags, including British. U-Boat operations were reduced to patrols in the North Sea and attacks on British warships. The situation would remain until 1917, when the U-Boat war returned.
The Admiralty had long circumvented the cruiser rules by arming merchant ships and by instructing merchant captains to attempt to ram surfaced submarines rather than tamely submitting to search or surrender. The several ships captured by the Germans gave then copies of the same orders. Had U-20 surfaced and attempted to halt Lusitania on the high seas it would have been in extreme danger from the much faster and extremely larger ship. Some have cited the flaunting of the cruiser rules by the British as the real reason the submarine fired at Lusitania without first issuing a warning.