HMAS Derwent

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 Type 12 Rothesay Class frigates of the Royal Navy (RN), 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 40mm 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 and Stuart were the second pair of Type 12s 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. On 15 May 1964 Navy News described Derwent as ‘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’.

Derwent was launched on 17 April 1961. It was the second of three Type 12 anti-submarine frigates to be built at Williamstown and the fourth warship to bear the name–the previous three having served in the RN.

'Derwent' is the modern spelling of the Celtic word meaning ‘clear water’. The ship was named after the Derwent River in Tasmania, and was the first RAN ship to be equipped with an operational guided missile system, the Seacat, which would provide a capability out to 5000 yards. Initially designated as a frigate, HMAS Derwent was later reclassified a destroyer escort.

HMAS Derwent’s pennant number was F22 on commissioning in April 1964. This was later briefly changed to DE22, with the prefix standing for Destroyer Escort, before reverting back to F22. On 1 January 1969, the Royal Australian Navy adopted the numbering practice used by the United States (US), Canadian and Pakistan Navies, removing the pennant number letter prefix from its ships’ hulls. Derwent's pennant number became 49.

Derwent was commissioned into the RAN on 30 April 1964. On 25 May it became the first RAN ship to fire its Seacat guided missile, successfully shooting down a Pilotless Plane Target, the propeller of which was retained by the ship as a trophy. 

In December 1964 Derwent sailed on a three-month South-East Asian Treaty Organisation (SEATO) deployment. SEATO had been established under the auspices of the 1954 Manila Pact between Australia, New Zealand, the United Kingdom (UK), the US, the Philippines, Thailand, Pakistan and France. It was intended to be a vehicle for collective defence, in the same way as the North Atlantic Treaty Organisation (NATO). The regular involvement of Australian warships such as Derwent in large multinational exercises provided the RAN with a high operational tempo and valuable experience it would have otherwise lacked.

In the early 1960s the new nation of Malaysia was proclaimed. Indonesia opposed this and embarked on a policy of ‘confrontation’. The Australian Government stated its resolve to defend Malaysia from invasion subversion and RAN warships in the Strategic Reserve based in Singapore were made available for naval patrol and escort operations to counter possible Indonesian attacks. During its first SEATO deployment, Derwent was at anchor off Tawau, Sabah, acting as guardship. The main task of the guardship was to provide naval gunfire support as required, as a deterrent to Indonesian activities.

In mid-February 1966, in company with the destroyer HMAS Vampire, Derwent embarked on a six-month tour of duty as part of the Commonwealth Strategic Reserve, under the Australian Government’s military commitment to its policy of ‘forward defence’ and regional security and stability. During this deployment, Derwent undertook patrols in the Singapore and Malacca Straits as part of the naval force deterring incursions by Indonesian warships, and preventing movement by armed parties of Indonesians in local trading boats. 

During March 1966, Derwent was again assigned the duty of Tawau guardship. Derwent’s Commanding Officer reported:

…because firepower in the Tawau area is limited it is accepted that the guardship could be called upon at short notice to provide Naval Gunfire support to our troops ashore. To this end Derwent during the period in Tawau from 22-31 March has carried out three operational shoots...and formed a good liaison with the Naval Gunfire Support Observer ashore. It is intended to carry out at least one bombardment per week using both ground and air spot during the ship’s tour of duty.

In 1967, on route to Hobart for an official port visit, Derwent was redirected to support bushfire response operations. Within two hours of arriving in Hobart, the ship’s company was fully involved fighting bushfires and other relief efforts. As recounted in Navy News:

During their stay they established communication facilities between Tasmania and the mainland. They also provided continuous assistance in many and varied activities conducted by the Civil Defence authorities, and their talents were not overtaxed by such tasks as burning firebreaks, ditch digging, rebuilding burned out bridges, providing a fresh water pipe line to homeless victims of fire in Snug. When the ship returned to Sydney...she carried messages containing the thanks of the Governor of Tasmania, Sir Charles Gairdner and the Lord Mayor of Hobart. The message from the Governor read: "On behalf of all in Southern Tasmania I would like to thank the ship’s company for all its efficient, willing and unassuming work in assisting during the bushfire crisis...

In October 1968, Derwent deployed to Southeast Asia. In December Derwent and HMAS Duchess undertook an 11-day flag showing visit to Korea and Japan. At Seoul, Derwent’s divers spent a day assisting in the construction of the Colombo Plan Dredge Australian Endeavour, which was a gift from the Australian Government. The ship also gave a party for 65 children from a local orphanage.

In Nagasaki, Japan, Derwent and Duchess were both open to public, and despite unpleasant weather, received over 1000 visitors. Christmas and New Year saw Derwent alongside in Hong Kong for a self-maintenance period. 

In April 1970 Derwent participated in exercise SEA ROVER. SEA ROVER was the 37th exercise to be conducted by SEATO member nations since the organisation was formed in 1954. Some 40 ships from Australia, New Zealand, the Philippines, Thailand, the UK and the US were involved. Apart from Derwent, Australia’s contribution included HMA Ships Yarra, Duchess, Oxley and Melbourne.

Exercise CRACKSHOT was the next multi-national naval activity. On completion of this, more than 30 ships of the Australian, UK Malaysian and New Zealand Navies, Derwent included, made a ceremonial entry into Singapore Naval Base.

Derwent next took part in BERSATU PADU. This was an international exercise designed to train the military forces of Australia, Malaysia, New Zealand, Singapore and the UK in combined operations under the conditions which would prevail following the forthcoming withdrawal of UK forces from the region. The main phase took place in June 1970, and involved a large RAN task group.

In mid-May, Derwent sailed south for further exercises with the Commonwealth Strategic Reserve, before returning to Sydney on 15 July 1970, via Darwin and the inner Barrier Reef. Derwent commenced a seven-month refit at Williamstown Naval Dockyard on 25 July 1970.

Derwent commenced a further tour of duty with the Strategic Reserve on 5 June 1971. Derwent made 17 port visits, including Guam, Kagoshima, Okinawa, Hong Kong, Subic Bay, Singapore, Bangkok, Ko Samui, Manila, Tacloban and Vung Tau. The visit to Hong Kong in July was interrupted by Cyclone Lucy.

In October 1972, Derwent and other RAN units were involved in Exercise SEA SCORPION in the South China Sea. More than 20 ships plus aircraft from the six SEATO nations took part in the exercise, the main phase of which tested convoy protection from submarine and air attack.

In mid-November 1972, Derwent and Brisbane, took part in the first bilateral exercise with the Indonesian Navy off Surabaya. Exercise CAKRAWALA BARU (New Horizons) took place on passage from Surabaya to Bali with five Indonesian Navy ships. The exercise involved general fleet manoeuvres, screening exercises, replenishment at sea and an impressive display of close range gunnery firings by the Indonesian ships. 

Following the drawdown of the RN in the Far East, the Australian Government became increasingly aware of the growing political and strategic significance of the Indian Ocean, and made the decision to explore common interests with littoral countries. To this end, the RAN became actively involved in a ‘Show the Flag’ deployment and on 19 February 1973, HMA Ships Perth, Derwent and Supply departed Fremantle for a three-month Indian Ocean goodwill and training deployment.

The first port of call was St Louis in Mauritius on 1 March, before sailing to Mombasa, Kenya. From Mombasa, Supply returned to Fremantle, while Derwent and Perth sailed for the Ethiopian Red Sea port of Massawa. At this point Derwent and Perth separated, with the latter visiting the Iranian port of Bandar Abbas, while Derwent called at Bahrain. On the homeward leg of the deployment, Perth and Derwent visited the Pakistan port of Karachi, Mumbai in India, the Sri Lankan port of Colombo and Medan in Indonesia.

The ships sailed on 26 April, and following exercises with Royal Australian Air Force Mirages and Royal Air Force Phantoms, and gunnery firings, course was set for Tandjuk Priok in Indonesia, where they arrived on 28 April for a short visit.

The Deputy Prime Minister and Minister for Defence, the Hon. Lance Barnard AO, described the cruise as: 

…highly successful in demonstrating Australia’s interests in the region. Australia considers itself as an Indian Ocean littoral state and the cruise had underline Australia’s involvement as a neighbour of those countries bordering the Indian Ocean. The ships and their men have created a great deal of interest and goodwill in the countries visited, and had effectively demonstrated Australia’s friendship and common interests with the people of the region. 

On 5 March 1975 Derwent, under the command of Commander M Ward RAN sailed from Sydney for a five-month deployment in the Far East. On route via Darwin, a working party of three officers and 38 sailors was landed and contributed to the ‘Navy Help Darwin’ operation by assisting in the demolition of houses that had been badly damaged by Cyclone Tracy.

Surabaya was the next port of call, followed by participation in Exercise ORION with the Indonesian Navy. Derwent arrived in Singapore on 31 March, as Australia’s contribution to the newly-formed Five Power Defence Agreement. After three days in port, Derwent sailed to participate in Exercise PENANGEX 6 in company with a RN task group. On completion of the exercise, the task group continued on passage to the UK, while Derwent returned to Singapore.  

Following the 1979 Soviet invasion of Afghanistan, the carrier HMAS Melbourne (III) led a task group comprising Perth, Derwent, Stalwart and Supply on an extended ‘flag-showing’ cruise through the Indian Ocean. Described by the Australian Government as the largest and longest RAN task group deployment since the Second World War, the operation clearly demonstrated the level of reach and autonomy attained by the RAN. This deployment included visits to Karachi, Singapore and Surabaya, and exercises with regional navies. Derwent was awarded the Commodore TE Wardle Cup for communications excellence from the ship’s participation in the 1979 Indian Ocean deployment. 

On 3 July 1981 Derwent decommissioned to commence a modernisation that would take four and a half years to complete.

The overall aims of the modernisation program were to:

• ensure the ship’s combat effectiveness 
• reduce naval personnel requirements
• improve habitability.

The modernisation refit saw many changes. The most obvious was the removal of the LWO 2 search radar from the foremast to a position further aft and situated lower down. The MR3 Fire Control System Director was replaced by a M22 Fire Control System radar ‘golf ball’ dome. Redesigned masts and funnel were also fitted. Two triple-tube surface launch torpedo mounts were installed while the Limbo Mortars were removed and the Ikara system upgraded.

Below decks, the installation of the Australian designed and built Mulloka Sonar was of note. Fuel efficiency was improved with steam atomizers being installed in the boilers. Also down below the 500kw Turbo Alternators were replaced with 750kw Turbo Alternators along with a new electrical switchboard.

Derwent was recommissioned by the Chief of Naval Staff Vice Admiral MW Hudson AO RAN on 6 May 1985.  

In 1987, Derwent was involved in Exercise WESTERN APPROACHES off the coast near Broome, followed by a Fleet Concentration Period (FCP). During the FCP, a missile shoot was scheduled against towed air targets and a derelict oil fuel lighter. Derwent’s Seacat aimer recorded two successful firings. The FCP was conducted over eight days and enabled the West Australian-based fleet units to exercise with their eastern seaboard counterparts. In the closing stages of the FCP, the RAN units conducted an opposed transit against the aircraft carrier, USS Constellation and its battle group.

Derwent, in company with Darwin, Torrens and Swan sailed from Fleet Base West on September 11 to join the US amphibious fleet off Fremantle for Exercise VALIANT USHER. This exercise involved a total of 27 ships from the RAN and USN and was conducted over a period of six days north of Lancelin.

Derwent participated in the arrival of the tall Ships and First Fleet into Fremantle on their journey to Sydney for the Bicentennial celebrations in 1988. 

1989 saw Derwent deploying north for a Far-East deployment for the third time in nine months. During March the ship conducted night encounter exercises with RMN Musytari, RMN Markin, RSS Sea Dragon, Sea Scorpion, USS Daring and USS Independence. The deployment included an official port visit to Madras, the first by an RAN warship in 10 years. In August 1989 Derwent participated in Exercise KANGAROO 89. On 24 January 1990, Derwent was presented with the prestigious Duke of Gloucester’s Cup for overall performance as a fleet unit in 1989. 

Derwent arrived at Stirling on Friday 29 July 1994. On arrival, the Chief of Naval Staff sent a message acknowledging Derwent’s contribution to Australia’s security as part of the RAN fleet:

...During her life Derwent saw service throughout South East Asia, the Indian Ocean, the South West Pacific and Hawaiian waters...Fittingly, Derwent’s final deployment this year included joint exercises with the Indonesian, Malaysian and Singaporean Navies. Throughout all these deployments, Derwent and her ship’s company have done much to foster and maintain close military and diplomatic ties in the region...By reputation Derwent has always been a happy ship, and one of which all who have served in, are justifiably proud. Farewell Derwent.

HMAS Derwent decommissioned at Fleet Base West on 8 August 1994. 

After decommissioning, Derwent continued to serve 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.