HMAS Derwent
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| Pennant | F22, DE22, and 49 (see text for details) |
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| Type | River Class Destroyer Escort (formerly designated as Anti-Submarine Frigate Type 12) |
| Laid down | 16 June 1958 |
| Launched | 17 April 1961 |
| Builder | HMA Naval Dockyard, Williamstown, Victoria |
| Commissioned | 30 April 1964 |
| Displacement | 2100 tons standard, 2700 tons full load |
| Length | 370 feet overall |
| Beam | 41 feet12.497 m 1,249.68 cm 0.0125 km 0.00777 mi 492 in |
| Draught | 15 feet4.572 m 457.2 cm 0.00457 km 0.00284 mi 180 in |
| Armament |
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| Main Machinery |
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| Horsepower | 30,000 SHP |
| Speed | 30+ knots |
| Complement | 247 (198 on decommissioning) |
The decision to acquire a new generation of frigates was announced in August 1950. The six new anti-submarine frigates were to be a modified version of the Royal Navy's Type '12' Rothesay Class frigates, but with improvements in habitability to meet specific Royal Australian Navy (RAN) needs.
In the event only four hulls were finally approved, with an armament of one twin 4.5 inch turret, one twin 40 mm Bofors Mk 5, two Limbo anti-submarine mortars and twelve 21-inch torpedo tubes. The ships also introduced a number of new capabilities, including a hull-mounted medium range sonar, and in the case of Derwent and Stuart, a Type 199 variable depth sonar that could be lowered below the surface temperature layer.
The 4.5 inch twin turret was designed as dual purpose, having both anti-surface and anti-aircraft capabilities. A crew of six was carried in the turret for loading and operation, and a further 18 below for supply of shell and cordite from the magazines to the gun bay and up to the turret.
Derwent, with her consort, Stuart, were the second pair of Type 12's to be ordered in 1958, but to a slightly modified design. Both ships featured a flushed hull on the portside aft, to accommodate a control room and deck space for their variable depth sonar. From Navy News, dated May 15 1964, "Derwent also is prepared for atomic warfare and has a ‘wetting-down’ device to cope with nuclear fall-out. An elaborately equipped operations room is the hub of the frigate. The ship can be controlled from this compartment, where a mass of dials and screens gives the Commanding Officer all available technical information."
The third of three Type 12 anti-submarine frigates to be built at Williamstown, Derwent was launched on 17 April 1961. "I name this ship, Derwent, I congratulate all those who have so faithfully and skillfully constructed her. May she be a valuable addition to the Royal Australian Navy, and may God's protecting care be over all who sail in her." With these words by Lady Burrell, wife of the First Member of the Naval Board, Admiral Burrell, Derwent was officially named and launched. She was the fourth warship to bear the name, with the previous three having served in the Royal Navy.
Pennant Number Changes
The pennant number of HMAS Derwent was initially F22 in 1964. This was later changed to DE22, with the prefix standing for Destroyer Escort. On 1 January 1969, the Royal Australian Navy adopted the numbering practice used by the US, Canadian and Pakistan Navies, removing the pennant number letter prefix from its ships' hulls. Derwent's pennant number thus became 49.
Ship History
1964 to 1969
1970 to 1979
1980 to 1994
Postscript
After decommissioning, Derwent continued to serve the nation when she was used as the platform for the Ship Survivability Enhancement Program (SSEP). The SSEP involved a series of fire, smoke, weapons effects and electronic experiments, with the data being used to enhance the combat survivability of ships and their crews to a range of weapons and associated threat effects.
 HMAS Derwent performs DSTO trails. |
 HMAS Derwent performs DSTO trails. |
 HMAS Derwent sinking. |
On completion of this valuable but destructive program which had inflicted greater cumulative damage than originally estimated, Derwent had been reduced to a hulk. The estimate to make the ship safe as a dive site was $500,000 and this was deemed to be beyond the then current Defence Budget. Accordingly, she was towed out to a position 12 nautical miles west of Rottnest Island and at 1446 local time on 21 December 1995, she was scuttled in deep water.
