21-in Long A.W. Torpedo Tube (UK)

The 21-in Long Above-Water Tube was a single revolving tube first used by the Acorn class destroyers and the Boadicea class cruisers.

It had a lip of 4 foot 6 inches, a liner of 13 feet and a rear end of 5 feet 6 inches. The tripper was 6 feet, 6.5 inches from the rear door. A powder impulse was employed. It was like the 18-in light pattern tube, except it had a swing door. It had a hand brake and locking pawl. It weighed 3,566 pounds.