The survey vessel HMNZS Lachlan had an involvement in the RNZN’s operations connected with the French atmospheric nuclear testing at Mururoa in 1973. Read about HMNZS Lachlans operational deployment.
The survey vessel HMNZS Lachlan had an involvement in the RNZN’s operations connected with the French atmospheric nuclear testing at Mururoa in 1973. It is understood that most of the material connected with the operation of this vessel remains classified. From a historical perspective, it would be somewhat embarrassing to the legacy of the Prime Minister of the time, Norman Kirk if it became widely known that the RNZN engaged in intelligence gathering whilst sending fully armed frigates as agents of protest to Mururoa. This act is at odds with his perceive place in our nation’s political history. There are sound operational reasons why such SIGNIT activity was necessary at the time. There was a sanitised Operational Order for Otago & Canterbury was issued in response to a Ministerial inquiry in July 1983. However, there was no request for material relating to Lachlan.
Once the new Labour government had entered Parliament in 1972 planning began for a naval operation to protest the atmospheric nuclear testing that the French were carrying out at Mururoa Atoll. New Zealand took a case to the International Court of Justice in 1973 but the naval planning ran alongside the public activity. Norman Kirk made it very clear during the election that he would be taking action on the issue.
21 June 1973 HMNZS Lachlan undertakes covert eavesdropping on French signals until 1 July.
28 June 1973 HMNZS Otago sails to Mururoa Atoll under orders from the Government to protest the atmospheric testing of nuclear weapons by the French.
21 July 1973 Otago arrives at Mururoa and observes the test.
25 July HMNZS Otago replaced on station by HMNZS Canterbury.
28 July 1973 HMNZS Canterbury observes the second test. This ends the deployment at the frigate returns to New Zealand.
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. Note that Otago had orders to fuse its shells for the voyage to the exclusion zone.
On 13 June 1973 the survey vessel HMNZS Lachlan was alongside at Apia after carrying out a survey of the approaches to and the harbour of Asau. That evening Wellington issued signal ordering the ship to remain at Apia pending further orders. The ship’s company provisioned the ship and rearranged the ship’s programme. A party of radio operators led by Lieutenant Commander Denis Milton where flown in to Apia by the RNZAF. Their task was to monitor radio signals broadcast from the Atoll to determine the strength and deployment of French naval vessels operating in the area. This was vital intelligence for the commanders of the two frigates that were destined to operate in the area around the Atoll.
The Commanding Officer of Lachlan in June 1973 was Commander Ian Munro. A decision was made to send ten ratings back to New Zealand to ease congestion aboard ship and volunteers were called for. Munro noted at the time that the ship’s company was convinced that they were to be sent to the Atoll. Ten volunteers came forward, five of those for family reasons. Some wives of men aboard Lachlan were in Fiji waiting to meet the ship supposedly due into Suva on 17 June. They were told that the ship was not coming to Suva but it is not clear if they were given the reason why that was so. On 28 May 1973 the RNZN issued a press release advised that Lachlan had left that day for Raoul Island, Suva, and Western Samoa. It was reported that she was carrying explosives for the government at Apia. After carrying out survey duties in Western Samoa she was expected back on 25 June. It does seem as if from this press release that the decision had not been made to use her SIGINT work in May and it was only made once she was in Western Samoa.
Lachlan departed Apia on the evening of Sunday 17 June 1973. The next morning she refuelled at Pago Pago and departed that afternoon for Rarotonga which she arrived at on Thursday 21 June. During the passage, the radio monitoring team took over the chartroom for their task. During the visit, some surveys were undertaken of the harbour by order of Munro on the 22nd. Because of a risk of a pest to the coconut trees the ship stood off each night. An approaching gale dragged the ship towards a reef. While trying to retrieve the anchor it was fouled and lost. Commander Munro chose to remain at sea riding out the gale from the afternoon of Friday 22 June through to Wednesday 27 June. As the ship was running low on fuel, Wellington arranged that the Royal Fleet Auxiliary tanker Tideflow refuelled Lachlan on 27 June. This took most of the day and was carried out off Rarotonga. The tanker was deployed in the area to evacuate British nationals if there was fallout from the testing at Mururoa. The British made it very clear to the New Zealand government and the RNZN that they were not supporting the NZ protest action. The logistics vessel, HMAS Supply that was providing support to the frigates did visit Rarotonga in-between supply runs so may have met up with the survey vessel but there is no mention of it in the reports of proceedings.
From 27 June the vessel remained off Rarotonga carrying out surveys and standing off at night. While this was going on, the radio monitoring team searched for French signal traffic. During this deployment, some of the ship’s company would be left ashore each night. As Hydrographer of the Navy, Commander Munro was asked by Wellington to calculate the direction from Mururoa Atoll from the RNZN radio station HMNZS Irrirangi at Waiouru. This information allowed the directional aerials at Waiouru to be set to gather SIGINT from any French radio signals picked up. The Report of Proceeding states as follows:
The next few days were spent off Rarotonga surveying during the day and standing out to sea each night. It was normal practice during the period to leave a proportion of the ships company, who had suitable accommodation, ashore overnight.
There is no mention of any special orders, the arrival on board of the radio monitoring team, or the SIGNIT gathering in the document.
On Sunday 1 July 1973 Lachlan was at anchor of Rarotonga. At 0000 that night, orders came from Wellington to return to New Zealand and discontinue the SIGINT operation. Due to the switch back to New Zealand time she left on 3 July. On 7 July Lachlan arrived at Devonport Naval Base. The Naval Staff deliberately kept Lachlan away from Otago so that the media party aboard the frigate would not report on Lachlan’s presence. Given the mission was very sensitive, the government of the day would have faced a political storm if it became knowledge that a naval vessel was operating in an intelligence role. As has already been stated, there were sound military and operational reasons for such an operation. The first operational report from Otago dated 3 July 1973 does not mention Lachlan but it does talk about operational security and the fact that mail drops were kept confidential. This would suggest that avoiding meeting up with Lachlan was a planned effort. There is every indication that the media party aboard Otago remained unaware of the SIGNIT operation as they would have been given no indication of another RNZN vessel in the vicinity. Again, there is no mention of her SIGNIT gathering or the offloading of the radio monitoring team and their equipment. But it must be emphasised that she did not operate anywhere near Mururoa or be exposed to any nuclear fallout.
The operational orders issued to Otago state the level of risk:
For a ship at a minimum distance of 12 miles up-wind from the nuclear detonation expected in the current tests, the only real hazard is from thermal radiation which can produce chorioretinal burns. To guard against the risk of severe eye damage the precautions…are to be strictly observed.
This included goggles for those on the bridge and anti-flash gear. The level and extent of the protocols around the nuclear test for the frigates was not repeated for Lachlan. The observation area selected for the frigates was as follows:
Sea area to the west of Mururoa in a sector centred on western extremity of Mururoa 21° 53S 139° 02W between true bearings of 230 and 300 between radii 20 and 30 nautical miles.
There is no indication or information that Lachlan was ever in this area as set out in the operational order. Given that the French had declared a surface danger zone of 120 nautical miles radius centred on Mururoa, there is no reason for Lachlan to enter this zone. As it is, it appears from the operational order that it was not given to the Commanding Officer of Lachlan. There is also the issue of flyovers by French naval aircraft. Both frigates encounted French aircraft and vessels during their deployment. One test that could be applied would be to see if the requestor can name any aircraft and dates. Given that no French aircraft were operating near Rarotonga it is not possible for Lachlan to have seen any aircraft or vessels as they were committed to patrolling the danger area well to the north.
To the matter of the devices tested. There is a misconception that these were full size nuclear weapons. This is not the case in the tests of July 1973. measurements taken by Otago on 21 July 1973 indicated a low-yield range device, most likely a nuclear trigger. The precautions referred to earlier were more than sufficient to protect the crew. Any radiation hazard was negated by being up-wind and the yield of the device.
EXL 0002 HMNZS Lachlan Research Folder RNZN Museum
EXN 0010 French Nuclear Testing at Mururoa 1973 RNZN Museum
HMNZS Lachlan Log Books for June-July 1973 – held at ArchivesNZ – accessed by Gerry Wright for his book.
HMNZS Lachlan Reports of Proceedings June-July 1973 – Accessed by Gerry Wright for his book.
Gerry Wright, Mururoa Protest: The Story of the Voyages by HMNZ Ships Otago and Canterbury to Protest Against the French Atmospheric Nuclear Tests at Mururoa Atoll 1973, Woollahra: Bellona Books, 2008.
___________, ’30 Years Ago: The Navy at Mururoa’, The Raggie 17:3 (2003), p. 6.
 Operational Order 1/73 25 June 1973, marked by hand as being a “sanitised version released in response to Ministerial inquiry 18 July 1983” : EXN 0010 French Nuclear Testing at Mururoa 1973
 Supplementary Directive for RNZN Ships deployed as a National Protest Against French Nuclear Tests in the Pacific undated: EXN 0010 French Nuclear Testing at Mururoa 1973. An undated narrative prepared in 1973 makes the point that Otago was on a war footing.
 Gerry Wright, Mururoa Protest: The Story of the Voyages by HMNZ Ships Otago and Canterbury to Protest Against the French Atmospheric Nuclear Tests at Mururoa Atoll 1973, Woollahra: Bellona Books, 2008, p. 26. Wright quotes verbatim from the Report of Proceedings n his book without referencing to it.
 ibid., p. 27.
 ibid. See also HMNZS Lachlan Report of Proceeding for June 1973, p. 2.
 Copy of press release dated 28 May 1913: EXL 0002 HMNZS Lachlan Research Folder RNZN Museum
 HMNZS Lachlan Report of Proceeding for June 1973, p. 2.
 ibid., pp. 2-3.
 ibid., p. 3.
 Gerry Wright, Mururoa Protest: The Story of the Voyages by HMNZ Ships Otago and Canterbury to Protest Against the French Atmospheric Nuclear Tests at Mururoa Atoll 1973, Woollahra: Bellona Books, 2008, pp. 27-29.
 Gerry Wright, ’30 Years Ago: The Navy at Mururoa’, The Raggie 17:3 (2003), p. 6.
 Gerry Wright, Mururoa Protest: The Story of the Voyages by HMNZ Ships Otago and Canterbury to Protest Against the French Atmospheric Nuclear Tests at Mururoa Atoll 1973, Woollahra: Bellona Books, 2008, pp.30-31.
 HMNZS Lachlan Report of Proceeding for June 1973, p. 3.
 ibid., p. 1.
 HMNZS Otago Mururoa Operation Report No. 1 dated 3 July 1973: EXN 0010 French Nuclear Testing at Mururoa 1973.
 RNZN Operation Order 1/73 dated 25 June 1973 Paragraph : EXN 0010 French Nuclear Testing at Mururoa 1973.
 RNZN Operation Order 1/73 dated 25 June 1973: EXN 0010 French Nuclear Testing at Mururoa 1973.
 Annex E, RNZN Operation Order 1/73 dated 25 June 1973: EXN 0010 French Nuclear Testing at Mururoa 1973.
 Appendix 1 to Annex E RNZN Operation Order 1/73 dated 25 June 1973: EXN 0010 French Nuclear Testing at Mururoa 1973.
 Contemporary narrative prepared in 1973 by the Commanding Officer, HMNZS Otago, p. 8 : EXN 0010 French Nuclear testing at Mururoa 1973