>>21152359
The Q-Ship, or Decoy Ship has been a tactic of maritime warfare since earliest times. Put simply, it involves a ship flying the flag of a neutral or ally, with perhaps a false name and hidden armaments. This fools an attacker or target until it is too late, and the element of surprise is of great advantage to the 'victim' turned attacker.
These 'Trojan Horses' of maritime warfare were used by nations such as Britain France Holland and Spain since the 16th Century in an informal way. It was not until World War One that they were organised on a command scale. Winston Churchill, First Lord of the Admiralty, was credited with the organisation of the Royal Navy Q-Ships.
Haulbowline Dockyard, in Cork Harbour was responsible for the conversion of many mercantile steamers to armed decoy ships. The majority however appear to have been converted in larger navy yards such as Devonport.
Some Q-ships were not converted merchant vessels, but a type of naval ship called a sloop. These were single-screw naval patrol craft, but some classes had the passing appearance of a merchant ship.
https://www.corkshipwrecks.net/Qships.html