HMS Jason (J99)

HMS Jason was a Halcyon-class minesweeper. She was named after the hero in Greek mythology and was the sixteenth Royal Navy ship to carry the name Jason. She was laid down on 12 December 1936, launched on 6 October 1937, and was completed on 9 June 1938. She survived the Second World War and was sold in 1946 to become a cargo ship. She was eventually broken up in 1950. Her pennant number was originally N99, but was changed to J99 in May 1940.

The Halcyon class were a class of dedicated minesweepers, designed to be smaller and cheaper than the dual-purpose (minesweeping and colonial patrol vessel) minesweeping sloops that had been built since the late 1920s (i.e. the Bridgewater class, Hastings class and Shoreham class), which as their design evolved, were becoming increasingly focused on escort duties and becoming too large for use as minesweepers.

Jason was 245 feet 6 inches (74.83 m) long overall and 230 feet 0 inches (70.10 m) between perpendiculars, with a beam of 33 feet 6 inches (10.21 m) and a draught of 10 feet 3 inches (3.12 m) at deep load. Displacement was 835 long tons (848 t) standard and 1,330 long tons (1,350 t) deep load. Two Admiralty 3-drum water-tube boilers supplied steam to geared steam turbines driving two shafts. The machinery was rated at 1,750 shaft horsepower (1,300 kW) giving a speed of 17 knots (20 mph; 31 km/h).

Armament consisted of two QF 4 inch (102 mm) Mk V guns on High-Angle mounts and so capable of being used for anti-aircraft duties, with a close-in armament of one quadruple Vickers .50 machine gun mount. One of the 4-inch guns was removed during the Second World War, while the multiple machine guns were replaced by 4–8 Oerlikon 20 mm cannon. Up to 40 depth charges could be carried when used in the escort role. The ship had a crew of 80 officers and other ranks.

Before the war, HMS Jason carried out surveys of the English and Bristol Channels. She carried out two principal surveys during 1938 and 1939. She was unarmed until the outbreak of the Second World War.

Although HMS Jason had been designed as a minesweeper, in September 1939, she was converted into an antisubmarine vessel and assigned to 1st Anti-submarine striking force at Belfast. Her first minor damage sustained was on 12 October when she was grounded at Row Point. Repairs were completed by 17 October and she was deployed in home waters for convoy defence, but she put in for more repairs on 3 August 1940, this time because of problems in her boilers.

After the repairs, she was again deployed to convoy defence, this time in the North West Approaches, during which she came under repeated attack from German U-boats U-32 and U-28. Although HMS Jason was not damaged in the attacks, four merchant ships were lost and Jason picked up 18 survivors. After one month in that role, yet more repairs were needed after a collision with the rescue tug Scheldt, in which significant structural damage to her stem was sustained. This time repairs were completed at HM Dockyard, Rosyth, and she was, upon release, deployed to the Rosyth Escort Force to defend shipping to and from Clyde.

As part of the Rosyth Escort Force, she was again subject to U-boat attack in October whilst escorting Convoy HX 79 (totalling 49 ships) off Rockall. This was part of the most vicious U-boat attacks of the war, with ten ships being lost from Convoy HX 79 alone. HMS Jason, however, was undamaged and picked up 78 survivors on 19 October and a further 111 survivors on 20 October. None of the eight attacking submarines were sunk.