# Minesweepers of the Royal New Zealand Navy

Commissioned minesweepers and danlayers of the Royal New Zealand Navy (RNZN) from its formation on 1 October 1941 to the present. The RNZN was created two years into World War II. For coherence this article covers the war years from the start, and thus includes also the New Zealand minesweepers operating from the beginning of the war.

## World War II minesweepers

During World War II the RNZN operated 39 minesweepers and danlayers. This included 20 naval trawlers (13 Castle class, three Bird class and four Isles class), five converted trawlers, 10 converted merchant boats, and four danlayers.

### Naval trawlers

Naval trawlers were trawlers purpose built to Admiralty specification to operate as minesweepers and/or anti-submarine boats.

#### Castle class

Thirteen Castle-class naval trawlers were commissioned. Apart from James Cosgrove and Wakakura, all were built in New Zealand by government directive, circa 1942. They were 135 feet (41.1 m) long, displaced 540 tons standard or 612 tons loaded, and were designed for a complement of 27. The three-cylinder engine of 480 indicated horsepower (358 kW) from A & G Price of Thames gave a speed of 10 knots (19 km/h). The coal-fired boiler was of the Scotch marine type. The boiler size governed the size of ship that could be manufactured, and as boiler plate of the required size was not available, two completed boilers and some partly completed boilers were supplied from Britain.
| Name | Pnd | Admiralty number | Builder | Launched | Commissioned | Decommissioned | Career | Fate |
| HMNZS Aroha | T24 | T396 | Stevenson & Cook, Port Chalmers | 9 September 1942 | 12 May 1943 | 1945 | Served at Auckland | Sold to Red Funnel trawlers, renamed to Maldanna. Scrapped 1963 at Singapore. |
| HMNZS Awatere | T25 | T397 | Patent Slip, Wellington | 26 September 1942 | 26 June 1943 | 1945 | Served at Wellington | Sold to A. A. Murrell of Sydney, Then purchased by the UNRRA in 1946. |
| HMNZS Hautapu | T26 | T340 | Stevenson & Cook, Port Chalmers | 20 November 1942 | 28 July 1943 | 1947 | Served at Lyttelton | Sunk at Shelly Bay in 1966 |
| HMNZS Hinau | T17 | T399 | Senior Foundry Co., Auckland | 28 August 1941 | 23 July 1942 | 1945 | Served at Auckland | Hulk ran aground for use as a breakwater and shingle bin between 1955-58 |
| HMNZS James Cosgrove | T10 | | Ailsa Shipbuilding Co. | 5 March 1918 | 10 October 1939 | 1944 | Served at Auckland | Sunk in 1952 |
| HMNZS Maimai | T27 | T338 | Stevenson & Cook, Port Chalmers | 25 February 1943 | 15 September 1943 | 1945 | Served at Wellington | Scrapped in 1966 |
| HMNZS Manuka | T19 | T401 | Mason Bros, Auckland | 23 September 1941 | 30 March 1942 | 1945 | Served at Auckland | Sunk in 1952 |
| HMNZS Pahau | T28 | T351 | Stevenson & Cook, Port Chalmers | 3 April 1943 | 12 February 1944 | 1945 | Served at Wellington | Sold to A. A. Murrell of Sydney then purchased by the UNRRA in 1946. |
| HMNZS Rimu | T18 | T402 | Seager Bros Shipbuilders Ltd | 9 September 1941 | 15 July 1942 | 1945 | Served at Auckland | Hulk sunk by the RNZAF 1958 |
| HMNZS Tawhai | T20 | T348 | Seager Bros Shipbuilders Ltd | 20 July 1943 | | | | Never commissioned. Sold to the UNRRA in 1946. |
| HMNZS Waiho | T34 | T403 | Stevenson & Cook, Port Chalmers | 19 February 1944 | 3 June 1944 | 1946 | Served at Auckland | Sold to Red Funnel trawlers, renamed to Matong Scrapped 1964 Singapore. |
| HMNZS Waikato | T30 | T343 | Mason Bros, Auckland | 16 October 1943 | | | | Never commissioned. Sold and renamed to Taiaroa, sunk by the RNZAF in 1989 |
| HMNZS Waima | T33 | T349 | Stevenson & Cook, Port Chalmers | December 11 1943 | 28 March 1944 | 1946 | Served at Lyttelton | Sold to Red Funnel trawlers renamed to Moona. Scrapped 1964 Singapore. |
| HMNZS Waipu | T32 | T357 | Stevenson & Cook, Port Chalmers | 1 August 1943 | 17 November 1943 | 1946 | Served at Auckland | Sold to Sanford Ltd in 1946 1955 renamed Mulloka for Red Funnel Trawlers. Scrapped 1964 Singapore. |
| HMNZS Wakakura | T00 | | Port Arthur Shipbuilding, Port Arthur | September 1917 | 1926 | 1947 | 1926–1941 was HMS Wakakura in the New Zealand Division of the Royal Navy. Used as danlayer from July 1944. | Scrapped in 1953 |

##### Cancelled

| Name | Pnd | Builder | Cancelled | Notes |
| HMNZS Konini | | Stevenson & Cook, Port Chalmers | April 1943 | Originally ordered as a composite minesweeper, then steel. Previous chosen names were Miro and Ngaio. |
| HMNZS Waiau | T31 | Mason Bros, Auckland | October 1943 | Previous chosen names were Konini and Kapuka. |
| HMNZS Wai-iti | | Stevenson & Cook, Port Chalmers | 1 October 1943 | |
| HMNZS Waikaka | | Stevenson & Cook, Port Chalmers | October 1943 | Fabrications of the hull had started. |

#### Bird class

The Bird-class naval trawlers were 168 feet (51.2 m) long, displaced 923 tons full load, and could manage 13 knots (24 km/h). They had a complement of 33–35 and were armed with one 4-inch (102 mm) gun, two Hotchkiss guns in single mounts, twin Lewis guns and 40 depth charges. They were equipped with asdic.
| Name | Pnd | Commissioned | Decommissioned | Career | Notes |
| HMNZS Kiwi | T102 | 1941 1948 1951 | 1946 1949 1956 | AS MS Training ship Training ship | On 29 January 1943, along with Moa, she rammed and wrecked the Japanese submarine I-1 |
| HMNZS Moa | T233 | 1941 | 1943 | AS MS | On 29 January 1943, along with Kiwi, she rammed and wrecked the Japanese submarine I-1. Moa was sunk by enemy aircraft on 7 April 1943 near Tulagi Harbour in the Solomon Islands. Five crew men were lost. |
| HMNZS Tui | T234 | 1941 1952 1956 | 1946 1955 1967 | AS MS Training ship Research ship | On 19 August 1943 Tui and some US Kingfisher floatplanes jointly sank the Japanese submarine I-17. |

#### Isles class

The Isles-class naval trawlers were 164 feet (50.0 m) long, displaced 740 tons full load, and could manage 12 knots (22 km/h). They had a complement of 40 and were armed with one 12-pounder gun, three 20mm Oerlikons in single mounts and depth charges.
| Name | Pnd | Commissioned | Decommissioned | Fate |
| HMNZS Inchkeith | T155 | 1941 | 1946 | Sold to G A Sparrey August 1958. Broken up at the Lighter basin in Freemans bay, 1959 |
| HMNZS Killegray | T174 | 1941 | 1946 | Sold to G A Sparrey August 1958. Broken up at the Lighter basin in Freemans bay, 1959 |
| HMNZS Sanda | T160 | 1941 | 1946 | Sold to G A Sparrey August 1958. Broken up at the Lighter basin in Freemans bay, 1959 and hulk was used as a shingle bin near Waikauri Bay, Takatu along with Humphrey. Hulk towed back to Auckland 1970 and scrapped. |
| HMNZS Scarba | T175 | 1941 | 1946 | Sold to G A Sparrey August 1958. Broken up at the Lighter basin in Freemans bay, 1959 |

#### Strath class

| Image | Name | Pnd | Launched | Commissioned | Decommissioned | Career | Fate |
| | HMNZS Humphrey | T06 | | 1941 | 1944 | | Hulked for use as a shingle bin near Waikauri Bay, Takatu. Hulk towed back to Auckland in April 1970 and scrapped. |
| | HMNZS Thomas Currell | T11 | 1919 | 1941 | 1944 | Served at Auckland | Deliberately ran aground at Port Hutt, Chatham island in 1968 |

### Other types
#### Converted trawlers

These vessels were usually armed with a quick-firing 4-inch (102mm) or 3-inch (76mm) gun on a raised bow platform, some machine guns, and depth charges. Vessels used for minesweeping were also fitted with minesweeping and mine handling equipment.
| Image | Name | Pnd | Launched | Commissioned | Decommissioned | Career | Fate |
| | HMNZS Futurist | T09 | | 1941 | 1944 | Functioned as a boom gate vessel 1944 | Sunk 19 March 1947 near the Flaxbourne River mouth |
| | HMNZS South Sea | T08 | | 1941 | 1942 | Served at Wellington | Previously HMT Ferriby of the Royal Navy, launched as a civilian trawler in 1913. Sunk 19 December 1942 in collision with inter-island ferry Wahine in Wellington Harbour |

#### Converted merchant boats

These ships were usually armed with a quick-firing 4-inch gun, machine guns and autocannon. Vessels used for minesweeping were also equipped with the appropriate equipment.
| Name | Pnd | Admiralty number | Commissioned | Decommissioned | Career | Fate | Notes |
| HMNZS Breeze | T02 | T371 | 1942 | 1944 | | Sold to Manila, Philippines 1964. Name changed to Balabac 1966 | |
| HMNZS Duchess | T07 | | 1940 | 1945 | examination vessel 1942–45 liberty launch 1945 | Hulk ran aground at Wreck Bay, Rangitoto Island | |
| HMNZS Gale | T04 | T370 | 1941 | 1944 | | Broken up 1970 | |
| HMNZS Hawera | T16 | T398 | 1941 | 1945 | Functioned as supply ship in 1945. | Sank at the Western Viaduct 1952, Refloated and beached in St Mary's bay but was removed 1956-57 | |
| HMNZS Kapuni | T15 | T400 | 1941 | 1945 | Functioned as patrol boat 1940 and supply ship 1944–45. | Broken up 1971 | |
| HMNZS Matai | T01 | T372 | 1941 | 1946 | Functioned as transport ship 1945–1946. | Broken up 1965 | |
| HMNZS Muritai | T05 | | 1941 | 1946 | Functioned as training and cable-lifting ship 1945–1946. | scuttled off an island in Hauraki Gulf on 7 September 1963. Refloated and broken up at Auckland in 1971. | |
| HMS Puriri | T02 | | 1941 | | | 14 May 1941 struck a German mine 9 miles (14 km) NE of the Whangarei heads and sunk with the loss of 5 crew members. | Puriri was sunk just before the creation of the RNZN. |
| HMNZS Rata | T03 | | 1941 | 1943 | | Broken up at Hong Kong 1959 | |
| HMNZS Viti | | T373 | 1941 | 1945 | Operated at Fiji, and would visit New Zealand annually. | | |

#### Danlayers

| Name | Pnd | Type | Commissioned | Decommissioned | Career | Fate |
| HMNZS Coastguard | T12 | Converted trawler | 1941 | 1960 | Functioned as a stores ship 1945–1960 | Now the office for Heartland Timbers. Name changed to Kaikohe post RNZN ownership |
| HMNZS Kaiwaka | T14 | Converted merchant ship | 1941 | 1945 | | Scuttled November 1989 |
| HMNZS Nora Niven | T23 | Converted trawler | 1941 | 1944 | | Scuttled off Taiaroa Heads 1947 |
| HMNZS Phyllis | T22 | Converted trawler | 1943 | 1944 | | Ran aground 1954 |

### COMSOPAC

COMSOPAC is an acronym for Commander South Pacific. During World War II, one of the major United States theatre commands was the command of the South Pacific Area. This command was usually referred to as COMSOPAC (COMmander SOuth PACific)
It was formed in April 1942 as a subordinate command of Pacific Ocean Areas, commanded by Robert L. Ghormley through October 1942, William Halsey, Jr. to June 1944, John H. Newton to March 1945, and William L. Calhoun to the end of the war.
In June 1942 New Zealand passed the operational control of most of its South Pacific naval forces to COMSOPAC. This continued until COMSOPAC released control in June 1945.
The headquarters for COMSOPAC were initially located in Auckland, New Zealand. In July 1942 they were transferred to Nouméa, New Caledonia,

### The 25th Minesweeping Flotilla

In the early months of World War II the New Zealand minesweepers had no formal grouping as a flotilla Then Niagara was sunk in June 1940. On 18 July 1940 the Naval Board designated the First Group for coastal minesweeping, and allocated Port minesweepers to the main ports. They were:
On 14 November 1940, a few weeks after the founding of the Royal New Zealand Navy, they were reorganised as the First Minesweeping Flotilla (NZ)
Then on 23 December 1940 the Port minesweepers were separated, and the remaining minesweepers were organised into the 25th Minesweeping Flotilla. This name aligned with the flotilla names used by the Royal Navy. The makeup of this flotilla changed during the course of the war, as new minesweepers were commissioned, others sunk or withdrawn for repairs or refitting, and requirements changed.
Here is a snapshot of the 25th Minesweeping Flotilla on 27 March 1943:
The Port minesweepers were organised into their own flotillas. Eleven new Castle-class minesweepers joined the Port flotillas on completion, 1943–1944.

## Post war
### Ton class

The RNZN operated two Ton-class minesweepers on anti-infiltration patrols in Malaysian coastal waters during 1966 and 1967. They are the only commissioned RNZN ships never to have visited NZ.
| Name | Dates | Career | Fate |
| HMNZS Santon (M1178) | 1965–1966 | | 1967 sold to Argentina and renamed ARA Chubat (M3) |
| HMNZS Hickleton (M1131) | 1965–1966 | | 1967 sold to Argentina and renamed ARA Neuquen (M1) |
These Admiralty designed coastal minesweepers were built with composite hulls of wood on aluminium frames and a minimum of magnetic material in the hull. They were intended to meet the threat of seabed mines laid in shallow coastal waters. Their shallow draft gave them some protection against pressure and contact mines, and allowed them to navigate in shallow inshore waters. They were 153 feet (47 m) long, displaced 360 tons standard, could manage 15 knots (28 km/h), and had a complement of 32. They were named after British villages which ended with "ton".
Early in 1965 Indonesia was employing a policy of confrontation against Malaysia. New Zealand agreed to assist Malaysia by deploying two Royal Navy minesweepers then in reserve at Singapore. These were commissioned into the RNZN on 10 April 1965 and joined the Royal Navy's 11th Minesweeping Squadron (also Ton class), taking part in anti-infiltration patrols in Malaysian waters.
In their first year they carried out 200 patrols, with 20 incidents involving intruding Indonesians, often taking as prisoners those aboard intercepting small craft. By the time the Indonesian confrontation policy ended in August 1966 Hickleton and Santon had jointly steamed 130,000 miles (210,000 km).