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Lachlan – Frigate

In 1948 the New Zealand Government sought a survey ship on loan and Lachlan was offered after negotiations on the term of the loan which initially was to be three years. During the Waterfront strike of 1951 Lachlan was deployed to Dunedin where her ship’s company worked the wharves. Detachments from there were sent to Westport to work in the coal mines and operate the wharf.

Ship Details:

Class: River-class frigate

Dimensions: 91.8 x 86.3 x 11.2 x 4.3m

Displacement: 2220 tonnes fully loaded

Machinery: 2 x shaft, two Admiralty 3-drum boilers, 4 cylinder Triple expansion oil fired ihp 550 = 20 knots

Armament: All armament removed in 1949 for RNZN survey duties

Complement: 140 in RNZN service

Pennant Number: F364

Taken over: 1 June 1949

Commissioned: 5 October 1949

Paid off: 13 December 1974

Motto: Safe and Sound

Name: A river that flows through south-central New South Wales

Survey Boats: Acheron, Albatross, Pandora, Penguin, and Seagull (Also deployed on HMNZS Monowai)


The River-class frigates were designed to meet a need during the Second World War for an Anti-Submarine escort ship better suited to conditions in the Atlantic that the smaller single screw Flower and Castle-class corvettes. This type of frigate was built in Britain, Canada, and Australia. Lachlan was one of twelve River-class frigates built in Australia for the Royal Australian Navy. Lachlan was laid down at Mort’s Dock and Engineering Co. at Balmain, Sydney on 22 March 1943. She was launched on 25 March 1944 and completed by 14 February 1945.

Royal Australian Navy Service:

Lachlan was commissioned into service with the Royal Australian Navy on 14 February 1945. She was to serve as a survey vessel. She was deployed overseas to survey landing zones at Tarakan in Borneo before and after the Allied landings there on 1 May 1945.  In June 1945 she surveyed Brunei Bay after the landings were carried out. During her survey work she was occasionally fired upon, suffering a damaged ship’s boat and some casualties on one occasion.

With the Japanese surrender in August 1945, Lachlan was sent to the Moluccas in September 1945 taking Australian army investigators looking for and arresting war criminals. She remained as part of the RAN’s Hydrographic Unit until 1948 when she was put into reserve at Fremantle and paid off.

Royal New Zealand Navy Service:

In 1948 the New Zealand Government sought a survey ship on loan while a new survey vessel was to be built in Britain. Lachlan was offered after negotiations on the term of the loan which initially was to be three years.  Therefore on 31 May 1945 HMAS Lachlan was paid off from service with the RAN and taken over the next day by the RNZN. A crew of RNZN personnel brought the ship out of reserve and prepared for passage to Auckland. After trials in September 1949 HMNZS Lachlan was formally commissioned into RNZN service on 5 October 1949. At the dockyard at HMNZS Philomel, the ship was fully disarmed and the chartroom enlarged for surveying. Such was the rush to get Lachlan into service as a survey vessel that new chartroom fittings were made at sea. part of the ship’s company included Hydrographic experts from the RAN and RN on loan to help establish the Hydrographic service.

The first survey undertaken began on 18 November 1949 which consisted of surveying the Wellington Harbour entrance to Cook Strait. Work was done in three weeks with the assistance of the survey motor boat brought from Australia. IN January 1950 Lachlan undertook a survey of Foveaux Strait and the harbour of Bluff. Both locations were a high priority for the new RNZN Hydrographic service. For the next twenty-four years over fifty percent of New Zealand’s coastline was surveyed by this vessel. There were also surveys carried in the Pacific and in Australia. She also assisted in clearing mines from the Second World War that were laid around the Gilbert & Ellice Islands.

In October 1954 her bow was badly damaged in a collision with the wharf at Napier. In June 1956 she rescued 18 men whose small motor vessel went down in the northern Tongan islands. In October 1963 Lachlan was sent to assist the RN survey ship HMS Cook that had struck coral in Fiji. In November 1965, she went to the aid of the stricken cruiser HMNZS Royalist struck with boiler problems south of the Solomon Islands. In 1963, after what was supposed to be a three-year ‘loan’, the New Zealand government purchased the vessel for £16,000.  By 1970 Lachlan was due to be decommissioned and disposed of. However, in May 1970 the government ordered the RNZN to extend her service for a further five years.

Specific Tasks

During the Waterfront strike of 1951 Lachlan was deployed to Dunedin where her ship’s company worked the wharves. Detachments from there were sent to Westport to work in the coal mines and operate the wharf. As with other vessels in the RNZN, Lachlan served as the guard ship at Waitangi for the Treaty celebrations as well as participating in the 1953 Royal Tour.  Non-military surveys were completed for the development of the Marsden Point Wharf (where New Zealand’s supply of petrol is imported) and the iron sand ports of Waipipi and Taiaroa. The survey boats were often deployed to the many lakes around New Zealand to carry out necessary work.

In 1956 the RNZN was requested by the RN to survey Christmas and Malden Islands in the Pacific. These islands would be used for Operation GRAPPLE, the series of atmospheric nuclear tests carried out by Britain in 1957 and 1958. In June 1973, before the frigates HMNZS Otago & Canterbury were deployed to Mururoa Atoll to protest the French nuclear testing, Lachlan was sent on a special mission but did not go to Mururoa Atoll. While the ship’s company was convinced that was her destination, there was no intent to dispatch her to the Atoll to observe the atmospheric tests. This was partly due to the fact she was not armed.

The programme was changed so that the vessel could conduct signal intelligence gathering and she spent the period from 21 June to 1 July 1973 steaming off Rarotonga tracking and eavesdropping on French Radio communications under the direction of Lt Cdr Milton who had embarked aboard especially for this purpose. Lt Cdr Milton had been involved in communication intercepts since 1944.  The Commanding Officer Cdr Monro also calculated for HMNZS Irirangi the bearing from Waiouru to Mururoa Atoll so that the directional aerials could be directed to listen into the French communications.  At the same time Lachlan undertook surveying of the Avatui Harbour and from Friday 23 June until Wednesday 28 June Lachlan remained at sea to gale force winds. At 0000 hrs 2 July 1973, HMNZS Lachlan received order from Wellington to return to New Zealand and it arrived at Devonport on Saturday 7 July. A course was sent to avoid HMNZS Otago that Lachlan‘s part in obtaining signal intelligence was kept from the media contingent aboard Otago.


Following the 1949 refit there were further modifications undertaken during service with the RNZN.

  • 1950 small oceanographic laboratory fitted
  • 1955 accommodation improved
  • 1958 two-range Decca navigation system (2RD) fitted
  • 1958 first survey boat fitted – Pandora
  • 1961 major refit
  • 1966 helicopter deck added (15.2×9.1m) – first ship to be fitted in the RNZN – designed for Wasp, Sioux and Miller 12 helicopters
  • 1970-71 Bridge enclosed


Her final survey session overseas occurred in July 1973. Her final New Zealand survey was completed in the northern waters. She arrived in Devonport on 28 May 1974. In September 1974 she deployed army personnel on exercises at Great Barrier Island. In November 1974 she departed on a farewell tour of New Zealand that was cut short after damaged sustained at sea between Gisborne and Napier. She returned to Auckland by the end of November and was paid off on 13 December 1974. In her service with the RNZN Lachlan covered over 804,000 kilometres at an average of 32,000 kms per year. Her service to New Zealand marine cartography cannot be underestimated.

In 1975, she was painted all grey and berthed at HMNZS Philomel as accommodation for ship’s companies whose frigates were undergoing refit. The engines were removed in September 1975 and sold.  In 1993, the hulk of HMNZS Lachlan was sold to a Philippines company.  In September she towed along with the decommissioned patrol craft Pukaki and Rotoiti by the Northland tug Herekino.

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