HMS Hedingham Castle (K491)

The Castle class were an improved corvette design over their predecessor Flower class. The Flower class was not considered acceptable for mid-Atlantic sailing and was only used on Atlantic convoy duty out of need. Though the Admiralty would have preferred Loch-class frigates, the inability of many small shipyards to construct the larger ships required them to come up with a smaller vessel. The increased length of the Castle class over their predecessors[2] and their improved hull form gave the Castles better speed and performance on patrol in the North Atlantic and an acceptable replacement for the Flowers.[3] This, coupled with improved anti-submarine armament in the form of the Squid mortar led to a much more capable anti-submarine warfare (ASW) vessel.[2] However, the design did have criticisms, mainly in the way it handled at low speeds and that the class's maximum speed was already slower than the speeds of the new U-boats they would be facing.[4]

A Castle-class corvette was 252 feet (77 m) long with a beam of 36 feet 8 inches (11.18 m) and a draught of 13 feet 6 inches (4.11 m) at deep load.[2][note 1] The ships displaced 1,060 long tons (1,080 t) standard[2] and 1,580 long tons (1,610 t) deep load.[4][note 2] The ships had a complement of 120.[2][note 3]

The ships were powered by two Admiralty three-drum boilers which created 2,750 indicated horsepower (2,050 kW). This powered one vertical triple expansion engine that drove one shaft, giving the ships a maximum speed of 16.5 knots (30.6 km/h; 19.0 mph).[2] The ships carried 480 tons of oil giving them a range of 6,200 nautical miles (11,500 km; 7,100 mi) at 15 knots (28 km/h; 17 mph).[4]

The corvettes were armed with one QF 4-inch Mk XIX gun mounted forward.[2][note 4] Anti-air armament varied from 4 to 10[2] Oerlikon 20 mm cannons.[5] For ASW purposes, the ships were equipped with one three-barreled Squid anti-submarine mortar with 81 projectiles. The ships also had two depth charge throwers and one depth charge rail on the stern that came with 15 depth charges.[4]

The ships were equipped with Type 145 and Type 147B ASDIC.[4] The Type 147B was tied to the Squid anti-submarine mortar and would automatically set the depth on the fuses of the projectiles until the moment of firing. A single Squid-launched attack had a success rate of 25%.[6] The class was also provided with HF/DF and Type 277 radar.[5]

Hedingham Castle, named for the castle in Essex, was laid down on 23 July 1943 by Henry Robb Ltd., at Leith.[7] At some point in 1943, the ship was transferred to the Royal Canadian Navy was launched on 26 January 1944.[8] Renamed Orangeville for the town in Ontario, the corvette was commissioned into the Royal Canadian Navy on 24 April 1944 with the pennant number K491.[7]

After commissioning, the ship worked up at Tobermory and in May 1944, joined the Mid-Ocean Escort Force as a member of the convoy escort group C-1. Orangeville spend the rest of the Second World War as a convoy escort, with her last convoy, ONS 48 westbound to Canada. After arriving in Canada, Orangeville was sent to Liverpool, Nova Scotia for a refit in May that lasted until August. Following the refit, the ship was placed in reserve at Halifax, Nova Scotia and was paid off at Halifax on 12 April 1946.[7]

The ship was sold on 5 September 1946 for mercantile use to Chinese interests and renamed Ta Tung in 1947.[7][8] Ta Tung had a gross register tonnage of 1,387 tons.[9] The ship was renamed twice in 1947, first as Hsi Ling, then as Shih Lin.[8][9] Registered at the port of Shanghai, the ship was first owned by the Chinese government. The ship was sold to the China Merchants' SN Company in 1948.[9] In June 1951, Hsi Lin was taken over by the Nationalist Chinese government, rearmed and renamed Te An and remained in service until being discarded in 1967.[7][8][note 5]