this armament, a load of 18 mines could be carried.
Perhaps the best known of the early T Class submarines was the ill-fated Thetis. Sailing in Liverpool Bay on the morning of 1st June and prior to handover, Thetis had on board her a 53-man crew and 50 passengers (shipyard and Admiralty men concerned with the trials). For her trial dive, Thetis was reluctant to submerge, so her six bow tubes were checked. When Numbers 1 to 4 were correctly found empty, Numbers 5 and 6 were tested to confirm that each contained sea-water. The test cock of No.6 tube squirted water but, strangely, the test cock of No.5 did not, and so was apparently empty. As there was only one way to be sure, the door was opened - and the sea roared in. Jammed by one of its clips, the watertight door couldn't be closed and, as two compartments flooded, Thetis nose-dived to the sea-bed 160
