World War I Decoy Ships
As a densely populated island nation, Britain relies on shipping for its survival. During WWI, the British were hard-pressed by German U-boats, whose predation on merchant shipping threatened to disrupt vital supplies and derail Britain’s war effort. As part of a multi-pronged strategy to beat back the U-boats, the British Royal Navy resorted to decoy vessels, known as Q-ships, which carried concealed weapons. When the U-boats surfaced to attack, the seemingly unarmed Q-ships would uncover their guns and sink the U-boats.
The British typically used freighters and trawlers with concealed guns in collapsible deck structures. Acting as bait, the decoys would sail routes known to be heavily infested with U-boats, in the hopes of attracting the attention of a German submarine and enticing it to make an attack. When hailed by the U-boat, a portion of the crew, known as the “panic party”, would act like normal merchant sailors, terrified by the sudden appearance of an enemy submarine, and rush to the lifeboats to abandon ship.
The use of expensive torpedoes to sink relatively easy targets such as trawlers and freighters was considered overkill, and was officially frowned upon. So U-boat captains would normally close the distance to the now “abandoned” ship, and open fire from close range and sink it with the deck gun. However, once the U-boat drew near, hidden crewmen remaining aboard the decoy would haul down the merchant flag and raise the Royal Navy’s ensign. Simultaneously, other crewmen would collapse the deck structure, revealing up to four guns manned and ready for action, which would open fire and sink the surprised U-boat.
The decoy ships were successful when first introduced, and within months, they sank 11 German U-boats. However, as the war progressed, experience taught German submariners to be wary and to approach small vessels with caution lest they turn out to be Q-ships carrying concealed weapons. If any suspicion was aroused, torpedoes were used to sink the target ship from a safe distance.
The decoy ships’ utility finally came to an end in 1917, when the Germans declared unrestricted submarine warfare and began sinking ships on sight and without warning. The decoy’s utility had depended on U-boats hailing them, then coming close enough for the armed merchantmen to surprise them. Once the Germans abandoned that standard operating procedure, the stratagem became useless.