H.M.S Hyderabad Bristol 1919
image above: H.M.S. Hyderabad (Mystery Ship) Bristol Harbour 1919.
The Q-ship HMS Hyderabad, unique as the only vessel designed specifically as a Q-ship. She was built in 1917 in Southampton, Hampshire, by Thorneycrofts. Above the waterline she looked just like an ordinary merchantship, but in fact her draught was 10ft less than most ships of her kind. It was a measure designed to allow torpedoes aimed at her to pass safely beneath.
Her tactics were draw a U-boat close enough on the surface for her hidden armament to open fire at near point-blank range. Her armament consisted of two 12pdrs (on fo’c’sle and aft), a 4in gun, hidden abaft of funnel, four Sutton-Armstrong bomb-throwers in cargo hatches, two Thorneycroft depth-charge throwers concealed on deck, four 18in torpedoes in Thorneycroft launching frames (one port, one starboard) hidden behind screens, and a small, unconcealed gun aft.
Any German submarine within 200 yards would be in serious trouble very quickly.