This painting by Thomas Wood depicts the ASDIC (sonar) hut on the corvette HMCS Drumheller, where members of the ship's crew operated equipment designed to detect submerged submarines.

The hut, installed as part of mid-war upgrades to corvettes, held a much-improved ASDIC system which helped make the corvette a more effective anti-submarine warship. ASDIC operators, like the two shown at centre and right, were highly trained, listening to sounds on headphones and watching range recorders, which visually plotted possible contacts on paper. A skilled operator could distinguish a submarine from marine life or other underwater phenomena.

ASDIC Hut, Corvette, His Majesty's Canadian Ship Drumheller
Painted by Tom Wood in 1944
Beaverbrook Collection of War Art
CWM 19710261-4841