QSHIP

Q-ship

Q-ships, also known as Q-boats, decoy vessels, special service ships, or mystery ships, were heavily armed merchant ships with concealed weaponry, designed to lure submarines into making surface attacks. This gave Q-ships the chance to open fire and sink them. The basic ethos of every Q-ship was to be a wolf in sheep's clothing.

The above text is a snippet from Wikipedia: Q-ship
and as such is available under the Creative Commons Attribution/Share-Alike License.

Need help with a clue?
Try your search in the crossword dictionary!