1st.ed., 1958. 223 pp., frontis + 26 other photo-plates + 6 maps & diagrams. Green cloth ; gilt. 21 x 15cm. V.G. On June 1st 1939, His Majesty’s newest submarine, THETIS, left her builder’s yard in Birkenhead and slipped quietly down the Mersey heading out to Liverpool Bay for her first diving trials. She had 103 men aboard, 50 more than her normal crew – only 4 would return alive. Five hours later the THETIS was lying bow down 160 feet below the surface, 38 miles from land. The first terrible disaster to strike the Navy’s third ‘T’ class submarine had begun. The authors, both ex-submariners themselves, devote most of the book to a tragedy that shocked the whole nation. With war clouds gathering the disaster had to be put aside and the THETIS was salvaged, returned to her builders for repairs, renamed THUNDERBOLT, and dispatched to the Mediterranean in time for war. Four years and one day after her fatal dive in Liverpool Bay, THUNDERBOLT was depth-charged and sunk – this time there were no survivors. This is the first full account of the submarine’s tragic history.