• Si Biggs

Port T - Secret Naval Base

Unit/ Formation: Royal Marines


Location: Addu Atoll


Period/ Conflict: World War II


Year: 1941


Date/s: September 1941


Early in the Second World War the threat posed from the Japanese military push into Malaya and the Indian Ocean, prompted the Admiralty to plan for the relocation of the Eastern Fleet to a fall back safe harbour. In 1941 the Royal Navy began searching for a safe, deep anchorage, in a suitably strategic position in the Indian Ocean, where a naval base could be established.


Addu met the requirements and a reconnaissance party consisting of Fleet Air Arm, Royal Artillery, Royal Engineers and Royal Navy personnel under the command of Lieutenant Colonel W. B. F. Lukis, Royal Marines, was dispatched from Ceylon to the Islands in the strictest secrecy aboard HMS Glasgow.


Permission to establish base facilities on the Islands was granted and work began in August 1941 to secretly develop a fleet anchorage and base known as "Port T”.


During September 1941, M.N.B.D.O. I in Egypt formed two detachments to embark for destinations in the Indian Ocean where they were to construct defended bases to be used for refuelling by the Royal Navy. Two of the bases were known as Port ‘T’, the codename for Addu Atoll, and Port ‘W’, the codename for an anchorage at Nancowry Island in the Nicobars. Coast defence guns were also to be installed at a third island, Diego Garcia.


In command of Force ‘Piledriver’ was Lt. Colonel W.B.F. Lukis, R.M. and whose main objective was to construct the defences and other facilities at Port ‘T’. Force ‘Piledriver’ would be assisted by Force ‘Shortcut’, commanded by Lt. Colonel L.O. Jones, which would later be detached to construct Port ‘W’. The personnel for Force ‘Shortcut’ were selected from Landing and Maintenance Unit, R.M., commanded by Lt. Colonel Jones, together with details from the 1st Coast Regiment, R.M. with four 4-inch guns and ancillary troops. The structure of the Force was:


H.Q. Landing and Maintenance Unit,

- Landing Company, R.M. - detachment Workshop Company, R.M., less details in Egypt - Boat Company, - ‘Z’ Battery, R.M. - A.M.T.B. Battery, R.M. - a signals section, - No.1 Tented Hospital, R.N.


The two forces left Egypt for the Indian Ocean on 20th September 1941 leaving behind the Transport Company and elements of the Workshop Company.

A view of the 'Hants' Battery and Headquarters Camp on Gan Island, Addu Atoll. (Imperial War Museum)

A group of 150 Royal Marine engineers under the command of Colonel Jones were landed in Villingili from HMS GUARDIAN to establish coastal batteries, searchlights, signal towers, roads, camps and jetties. An airfield was planned for use by the middle of May 1942 and the Island of Gan, approximately 1½ mile long by ¾ mile wide, was chosen as the location. The residents of Gan and the adjacent Island of Feydhoo were moved to the Maamendhoo area of Hithadhoo.


As told in the The War Illustrated;


The dramatic story of another secret war port was revealed by the Admiralty in July 1945.


"Port T" – a naval base with full defences – hacked out of the jungle on Addu Atoll, a collection of waterless coral islets in the Indian Ocean, 590 nautical miles from Colombo and 3,000 from Australia.


A Royal Marines workshop on Gan island, Addu Atoll. (Imperial War Museum)

Like the Mulberry, Pluto "Port T" was always known by its code name. Absolute secrecy was essential, for this port was a vital link on the convoy route to Australia and for certain operations in the Indian Ocean.


Now it is possible to tell how a force of Royal Marines drawn from the first Mobile Naval Base Defence Organization, working against time and tropical disease, began preparing this secret Fleet anchorage, while the Japs were still planning their attack on Pearl Harbour.


A Short Sunderland aircraft moored at Port T during the Second World War

The Royal Marines went ashore on Addu Atoll in September 1941. Their task was to establish coastal batteries, searchlights, signal towers, roads, camps, and jetties for a naval base.


The price they paid was heavy; 23 per cent of the whole force had to be evacuated in the first three months by the hospital ship Vita, as too ill to be of further service, but by the time Japan declared war the base was ready, and on January 3, 1942, the first convoy of the five troopships, escorted by the cruiser H.M.S. Emerald, put in to water and refuel.


From Wiki: The six major islands were garrisoned by the 1st Royal Marine Coast Defence Regiment, manning shore batteries and anti-aircraft guns. To facilitate the defence, causeways were built connecting the western islands of Gan, Eyehook (Abuhera), Maradhoo and Hithadhoo and, much later in the war, they were linked by a light railway. Read More/ Web Link:


The Burma Campaign - Force ‘Shortcut’ - Addu Atoll and Diego Garcia: Oct – Nov 1941


R.N. Air Station Addu Atoll



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