1970s

She was sent to Moruroa Atoll in 1973 as a symbolic protest of New Zealand against French nuclear testing.^[8] F421 small GP computer was able to assess the radiation level and its up to date electronic warfare sniffers immediately identify a French P-2 Neptune, on 50,52 IFF bands sweeping the area, flying low, with radar, ECM ESM and visual search for the location of unwanted naval, protest yacht and possibly submarine activity. She observed the 'Melpomène' nuclear test carried out on 28 July 1973,^[9] part of the 1971–74 French nuclear tests. It is the assessment of RAN officers that the presence of the modern RNZN warship, Canterbury, posed significant political and operational difficulties for the French and may have reduced the 1973 tests to 5 small bombs and been a factor why France never again conducted atmospheric testing.^[10] The NZ Labour Government admitted that not only France but the UK government opposed the use of its recently delivered British frigate on this mission.^[11] The French Government claimed in 1985 that the RNZ deployment to Muroroa in 1973 was one of the 'provocations that led to the attack by the French Intelligence service and Navy on the Rainbow Warrior in 1985.^[12] In November 1974, Canterbury deployed with Destroyer Squadron 5 of the United States Pacific Fleet off the West Coast for six months,^[13] the first time a RNZN frigate had operated as an integral part of a U.S. Navy force. While such joint operation was common for the RAN, it was not repeated in the 20th Century by the RNZN, possibly because while the deployment was approved by the Kirk/Rowling 3rd Labour Government, there was considerable official comment when the frigate returned to Devonport bearing the prominent insignia, US DESRON 5 and because integrated operations were restricted by lack of funding by the following Muldoon government for common Link 10 data link communication systems and baseline HYCOR chaff defence systems,^[14] and the standard for RNZN frigates was compatibility rather than commonality with, USN FF52 Frigates^[15]

In April 1977 Canterbury and the Australian destroyer HMAS Brisbane were assigned to escort the Australian aircraft carrier HMAS Melbourne during a five-month return trip to the United Kingdom for the Queen's Silver Jubilee Naval Review.^[16] Priority for a planned new frigate (either a Type 21 frigate or Dutch Kortanear) and modernisation of HMNZS Taranaki, projects later cancelled by the Muldooon government, meant F421 received only a 12-month refit in 1980 to maximise seatime, and its mid life refit was delayed to Nov 1987 to June 1990, at a cost of $73 million,^[17] the most significant changes fitting of Dutch LW08 long range surveillance radar, Phoenix electronic warfare systems and general replacement of radar and sonar with new solid state systems in place of the original obsolescent, British equipment. Updating was similar but more limited to that carried out of HMNZS Wellington, as F421 did not receive the extra fuel tanks and greatly increased cruising range of Wellington.

1980s

After the Argentinian invasion of the Falkland Islands in 1982, New Zealand Prime Minister Robert Muldoon offered to send Canterbury to join the Royal Navy's task force sailing south to retake the British territory ^{[citation needed]}. This offer was declined by the British government ^{[citation needed]}. Possible reasons for this included the facts that (1) The Leanders in RN service were past their prime^[18] (2) HMNZS Canterbury had had little updating since its completion in 1971 (3) It had dated, slow processing radar (4) It was not yet fitted with UK or US sourced chaff decoy systems (5) Its crew lacked practice in using them (6) Its crew had little Atlantic experience operating against Soviet naval vessels which might be observing in the South Atlantic (7) Only four Leanders, HMS Argonaut , HMS Penelope, HMS Minerva, and HMS Andromeda participated in the conflict; Bacchante joined the task group in the last week. The British government suggested as a less-controversial alternative that Muldoon send RNZN frigates to relieve the British frigate squadron in the Persian Gulf for Falkland duties. It was a difficult deployment with long stints at sea and infrequent runs ashore in very foreign ports for the crews.^[19] However they did feel closer to the Cold War action seeing significant Soviet warships and "Bear" surveillance aircraft.^[20]

Canterbury was built with a surplus 1960's RN Type 177 sonar, tuned for the Persian Gulf. The British MoD refused to fit the US Edo sonars (also planned for an RAN version of the Type 21 frigate rejected by the Australian Government in 1968)^[21] and the NZ government - on cost grounds - rejected the new Doppler 184M sonars fitted to HMS Apollo, Achilles and Diomede being built alongside Canterbury in the Yarrow yard^{[22][self-published source?]} The rather dated solid state sensors fitted were finally replaced as totally obsolescent, in the delayed mid life refit of the Canterbury between Nov 1987 and June 1990 costing $73 million. The fit was essentially similar to preceding refit of its sister broad beam, HMNZS Wellington, except Canterbury was not fitted with extra fuel tanks as RNZN and RN experience confirmed the modification difficult, dirty and expensive, on middle aged Leanders. The 1991 audit office review of the refit raised some issues, over the cost and need, for new 'long range' air surveillance,^[23] LWO8 radar, but lacked the background to assess the relevance of maintaining the Leander frigates, historical role, as a fleet radar picket for operating with the RN fleet or whether the 4.5 guns and Seacat missiles were still useful, given RN reassessment and more accurate reporting, by 1991 of their failure as AA weapons in the Falklands war of 1982.^[24]

During the Armilla patrols in 1982–83, the RNZN ships were not able to fully support the RN frigates Arrow and Galatea they were patrolling with in the Indian Ocean, because Prime Minister Muldoon refused to allow them to enter the Persian Gulf due to sensitivities with relations with Bahrain,^[25] The Arrow and Galatea were partly equipped for the missile age with computer datalinks and anti-missile decoy systems which fitting to RNZN frigates was delayed. Nevertheless, Canterbury and Galatea were later jointly awarded the Wilkinson Sword of Peace for the tour.

Canterbury was halfway across the Tasman in February 1985 when relations broke down with the US Government over nuclear ship visits. She visited the US later that year while en route to Canada for the 75th Anniversary of the Royal Canadian Navy (RCN) (port visits were made to Hawaii, San Diego and San Francisco.

1990s

Canterbury attended the 50th Anniversary of the Battle of Crete in May 1991. During that deployment, Canterbury became the last ship in the Royal New Zealand Navy to ever wear the distinctive white funnel stripe denoting the fact that she was the senior ship within the 11th Frigate Squadron when Captain Alasdair Clayton-Greene departed the ship in Lumut, Malaysia in April 1991. It was determined that only when a captain commanded a frigate (as the senior officer afloat) would this insignia be displayed – which never occurred again in the Royal New Zealand Navy.

In 1996, Canterbury was one of the ships tasked with enforcing the embargo against Iraq in Operation Delphic (under US Navy Control). She also was the first New Zealand Navy ship to visit China (in 1987), and has participated in a number of humanitarian and peace-keeping missions, for example to Samoa, Fiji or New Guinea.^[6]

Canterbury was deployed to East Timor as part of the Australian-led INTERFET peacekeeping taskforce.^[26] She conducted four patrols between 26 September to 12 December 1999. The patrols were tense, with the ship being approached by Indonesian naval vessels and Hawk jets. Her duties included escorting landing craft through territory disputed with Indonesia, being the Dili guard ship and patrolling East Timor's waters. Canterbury escorted the landing craft HMAS Tobruk when it landed a New Zealand infantry battalion in East Timor. During the deployment the ship achieved a remarkable 92% systems availability rate and had few mechanical defects, a considerable achievement for a ship of her age.^[27]

2000s

In the early 2000s, it was becoming increasingly clear that the ship's technical systems were getting old, and mechanical faults were multiplying. In October 2003, a fire broke out in the auxiliary switchboard while the ship was off the Chatham Islands. The ship was saved through quick action from 2 ratings, one of who received the New Zealand Order of Merit for his actions in the smoke-filled switchboard room, but it was considered that major damage or even ship loss had been only barely avoided. The repairs cost NZ$1 million,^[28] and the incident, confirmed the ships life had already been dangerously overextended due to delays on orders for replacement ships with newer multi-role vessels^[6] and possibly the forlorn hope that the eight-year old RN Type 23 frigate Grafton might have been approved as a replacement, it was instead sold to Chile.

Scuttling

It was expected that the ship would be able to be sunk late 2007, after potential contaminants and scrap materials had been stripped out, and the Department of Conservation had withdrawn its objections at the end of 2006.^[30] The intention was originally to sink her on Saturday 20 October 2007 – two days before its 36th commissioning anniversary.^[31] After some delays, on 3 November 2007 at 14:30 hrs^{[citation needed]} she was eventually sunk by imported plastic explosives placed at 12 locations around the hull (totalling only 14 kg (31 lb) in weight).^[33] The sinking was prepared by Norman Greenall, once Chief Petty Officer (shipwright) on Canterbury,^[34] who has undertaken the scuttling of other New Zealand Navy ships (like HMNZS Wellington). Greenall has a somewhat colourful reputation in the navy as the person who has "sunk more of our navy ships than the enemy did in the whole of the Second World War"^[28] – however, the actual sinking of Canterbury was performed by UK company Cadre One.^[34] Canterbury now lies on the seabed in Deep Water Cove.

The frigate offered good diving, especially with the ship being mostly intact (contrary to many similar dive wrecks which have broken up) and especially when other places such as Matauri Bay were unavailable due to weather conditions.^[35]

Sale to Hapu interests

The wreck was sold to Te Rawhiti Enterprises (the local Hapū) for one dollar (the same amount that the Canterbury Trust paid the New Zealand Navy) on 15 July 2008, and the Trust was wound up and dissolved on 17 November 2008.^{[citation needed]} The local Hapu will manage and market the wreck as their own to preserve their local heritage and preserve and enhance fish stocks. Due to depletion of stocks, a ban has been placed on fishing in the area for the time being, though there is still access to the wreck.^{[citation needed]}