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HDML Flotillas

In January 1942 the Admiralty agreed with the New Zealand government to allocate HDMLs to the RNZN. In February 1942 24 were ordered. Only 22 were to be supplied twelve by the United States under the Lend-Lease programme and ten from Britain. By end of 1943 the 124th and 125th Flotillas were operating in Wellington and Auckland.

Ship Details:

Displacement: 54 tonnes full load

Dimensions: 22 x 21.3 x 4.8 x 1.6m

Machinery: 1183-1194 2 x shaft Grey diesels bhp 330 = 10-12 knots

138-1351 2 x shaft Hercules diesels bhp 550 = 10-12 knots


1 x twin mount water cooled Browning .50-inch machineguns

1 x single mount 20mm gun

2 x twin mount Vickers .303 machineguns

8 x depth charges


Complement: 10 officers and ratings

HDML No.      Pennant No.   Began Service           Ended Service

1183                Q1183             9 March 1943              paid off September 1945

1184                Q1184             9 March 1943              paid off August 1945

1185                Q1185             8 April 1943                 paid off 11 October 1945

1186                Q1186             14 April 1943               paid off 23 October 1945

1187                Q1187             13 May 1945               paid off 19 September1945

1188                Q1188             22 May 1945               paid off October 1945

1189                Q1189             25 May 1943               paid off October 1945

1190                Q1190             28 May 1943               paid off 5 September 1945

1191                Q1190             28 September 1943    paid off October 1945

1192                Q1192             28 September 1943    paid off October 1945

1193                Q1193             28 September 1943    paid off October 1945

1194                Q1194             28 September 1943    paid off 5 October 1945

1348                Q1348             14 March 1944            paid off 26 November 1945

1349                Q1349             27 March 1944            paid off November 1945

1350                Q1350             27 March 1944            paid off 28 July 1945

1351                Q1351             14 March 1944            paid off July 1945


The Harbour Defence Motor Launch (HDML) was designed by the Admiralty in 1939 for harbour patrols and anti-submarine duties.  Many navies during the Second World War built HDMLs for patrol duties between 1940 and 1945. The Australian version was slightly longer at 24m and was reputed to have excellent sea-keeping qualities and was very robust while in service. Canada was the only major navy not to have built HDMLs.

In January 1942 the Admiralty agreed with the New Zealand government to allocate HDMLs to the RNZN. In February 1942 24 were ordered. Only 22 were to be supplied twelve by the United States under the Lend-Lease programme and ten from Britain. The provision of these vessels from Britain was abandoned and all the HDMLs for the RNZN were to be supplied from builders on the west coast of the United States.  This was due to the loss of one of the HDMLs when the ship carrying it was sunk by a U-Boat in July 1942. The vessels were completed between November 1942 and February 1943 but there were delays as the Grey diesel engines were required for the landing craft to be deployed for Operation NEPTUNE. The last four HDMLs were found to be unsatisfactory and needed further work before they could be delivered to New Zealand. The completed HDMLs were handed over to the United States Navy (USN) for delivery to the RNZN.  Sea and ASDIC trials were undertaken in a partially equipped state as no armament had been fitted.  The HDMLs would be sent to New Zealand as deck cargo on freighters as space became available as per the schedule below:

1183, 1184 via SS Frank Joseph Irwin arrived Wellington 118 January 1943

1185, 1186 via SS Pere Marquette arrived Wellington 5 March 1943

1187-1190 via SS Kootenay Park arrived Wellington 30 April 1943

1191-1194 via Mount Robson Park arrived Auckland 25 August 1943

1348-1351 arrived 28 February 1944

Upon arrival they were unloaded using a floating crane and then underwent full commissioning trials. The HDMLs were to take over from the NAPS vessels and were to be deployed at Auckland and Wellington as anti-submarine vessels.  The last six of the 22 allocated were transferred to the RAN in October 1943 as they were not required in New Zealand. The first HDMLs to arrive did work-ups in the Marlborough Sounds and Wellington before they were deployed to Auckland.

With the allocation of HDMLs to the RNZN the Admiralty also allocated Flotilla numbers as below:

124th Motor Launch Flotilla

Based: in Auckland from April 1943 – disbanded after last HDML paid off

HDMLs 1183 transferred to 125th Flotilla July 1944 – detached to Dunedin

1184 detached for service in Fiji November 1944 – returned December 1944



1187 transferred to 125th Flotilla 1 November 1943

1191 joined flotilla 28 September 1943 – transferred to 125th Flotilla 22 May 1944

1192   “           “           “

1193   “           “           “

1194   “           “           “

1348  joined flotilla March 1944- detached for Fiji service December 1944-Nov 1945       

1349   “           “            “                       paid off to C & M 8 July 1944 – to 125th Flotilla

1350   “           “           “

1351   “           “           “                       paid off to C & M 8 July 1944 – recommissioed January 1945 for service in Auckland

Patrol Area: Cape Brett, outer Hauraki Gulf, inner Hauraki Gulf, Waitemata harbour patrols

125th Motor Launch Flotilla

Based: Wellington from May 1943 – disbanded September 1945

HDMLs 1187   transferred from 124th ML Flotilla 1 November




1191  transferred from 124th Flotilla 22 May 1944

1349  recommissioned November 1944 to replace other HDMLs

Patrol Area: Approaches to Wellington Harbour and Cook Strait.

126th Motor Launch Flotilla

Based: Lyttelton

Was to have been four HDMLs 1348-Q1351 but with the improvement in the war situation in 1943 this flotilla was never formally established and the four vessels deployed with the 124th Flotilla.

Service with the RNZN:

By end of 1943 both the 124th and 125th Flotillas were operating in Wellington and Auckland. There was a proposed 126th ML Flotilla to be based at Lyttelton using HDMLs 1348-1351 but the delay in shipping to New Zealand and the improved war situation meant that the flotilla was never formally established and those HDMLs were allocated the 124th Flotilla. On 6 September 1943 1186 recorded an ASDIC contact off Cape Brett and dropped depth charges but there was no evidence a submarine was present. There were many contacts that were false signals.

In August 1944 it was proposed that one HDML be sent to serve in Fiji.  In November 1944 1184 departed Auckland for Suva escorted by Viti. In October the Admiralty requested that the HDMLs equipped with the Grey diesel engines be deployed with the British Pacific Fleet at the Forward Area which was the Manus Island naval base in the Admiralty Islands.  HDMLs 1183-1194 were accepted for service on 8 November 1944 and they were refitted for tropical service in December 1944. 1348 was detached for service in Fiji to replace 1184 which was escorted back to Auckland by HMNZS Kiwi in December 1944 who escorted 1348 to Fiji in January 1945.

By March 1945 there were six HDMLs at Auckland and Wellington awaiting orders to depart for Manus Island. The 124th Flotilla departed 12 April 1945 and reached the Forward Area via Norfolk Island and Noumea. Unfortunately not much is known about their service at Manus Island as it does not rate a mention in the official history. 1348-1351 were to be reformed as the 125th Flotilla.  In May 1945 the Admiralty advised that the other six refitted HDMLs were not now required for the British Pacific Fleet.  They returned to patrol duties as well as boom gate shipping control, exercises and other duties that RNZN could find a use for these vessels.  In June 1945 1192-1194 transferred to Wellington to join 1191 to re-establish the 125th Flotilla.

In June 1945 the HDMLs began to arrive in Auckland for paying off. On 13 September 1945 the 125th Flotilla was disbanded. In Auckland the HDMLs not paid off yet were used a boom control launches. 1348 returned from Fiji in November 1945.  Most of the HDMLs were laid up at Pine Island but 1184 was commissioned for service with HMNZS Philomel in November 1945.  Six HDMLs were to be retained by the RNZN and one 1185, was to be for use of the NZ Army.

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