25. Q-Ship Successes
The Q-Ships were initially quite successful, and within months, the decoy vessels had claimed 11 German submarines. However, as the war progressed, German submariners learned to be wary, and to approach small vessels with a healthy dose of caution, lest they turn out to be Q-ships carrying concealed weapons. At the slightest suspicion, torpedoes were used as a first option to sink vessels from a safe distance.
In 1917, the Germans turned to open submarine warfare, and began sinking ships without warning. That ended the utility of Q-Ships since their effectiveness had depended on U-boats hailing and coming close enough for the decoy ship to surprise them. Once the Germans abandoned that standard operating procedure, Q-ships became useless.