From 1919 until the early 1930s, little of consequence happened in the Fort. A 1922 plan of the Fort shows the 6 Inch QF Guns emplaced below Mount Siloso and the old empty emplacement atop Mount Siloso.
However, General Sir Webb Gilman’s visit to Singapore in 1927 would set in train some major changes. He had been sent by the British Government to plan new coast defences for Singapore. This in order to protect the naval base which was to be built on the north of the Island.
As well as major improvements for existing coast artillery forts, General Gilman recommended the construction of several new forts, with guns of up to 15 Inch in calibre. These would cover all sea approaches to Singapore, not just the Keppel Harbour approaches.
General Gillman was satisfied with the location of the gun emplacements at Fort Siloso, but thought the searchlights required some alteration. He was satisfied that the proposed location for an ACMB (AMTB) battery was satisfactory.
Two new Fire Commands would control the defence of sea approaches to Singapore, Changi and Faber. Changi Command would cover the eastern approaches to Singapore and the proposed naval base, and Faber the southern and western approaches to Singapore.
Between 1930 and 1939, the Fort was manned by the 3rd Hong Kong & Singapore (HKS) RA Battery. Their training and peace time quarters were at India Lines on Blakang Mati. The troops marched to and from their quarters each day. Other British Artillery units also used the Fort for training.
In the early 1930s, Fort Siloso began an upgrade to its armament and capability. With this, it would go to war. The Battery Command Post was enlarged into that seen today on Mount Siloso. The Inch QF Guns were retired from service. Mark VII 6 Inch BL Guns on Mark II CP (Centre Pivot) Mountings, and with a Mark IV Shield were emplaced where the QF Guns had been. This will have been around about 1932.
The Singapore Free Press, on 20 June 1932, carried an advertisement for the sale of 5,000lb of electrical cable from Fort Siloso. This will have been the cabling for the QF Guns, and other areas of the Fort.
Despite the upgrade, the 65 Inch Guns mounted were obolescent, although still effective. The much more modern and longer ranging Mark 24s with a Mark V Shield were later mounted at the Sphinx Battery on Pulau Tekong.
Part of the upgrade to the Fort involved the construction of new accommodation blocks for the soldiers. These overlooked the harbour. Several of these still exist.
Two Twin Lewis anti-aircraft guns were set up at the entrance to the fort, where in earlier days there were 12 Pounder QF Guns. Two machine gun posts were also constructed. The Mark VII 6 Inch BL Guns emplaced were not the most modern of weapons at that time. They had actually been superseded by the Mark 24. Of the 6 Inch Coastal Batteries in Singapore, only the Sphinx Battery on Pulau Tekong received the more modern longer range Mark 24 Guns.
On 2nd March 1936, in a cipher to the War Office, The G.O.C. Malaya, wrote about the 6 Inch Gun defences:
“In order to avoid manning difficulties I am prepared to do without the new 6 in. battery to be constructed at Labrador ......... If necessary, a third 6 in. gun could be mounted in reserve at Siloso. This will be desirable but not essential.”
The M.O.2, responding on the 4th March preferred a battery at Labrador saying:
“A Battery situated at Labrador will, in our opinion, get a better shoot at ships running into the Western approach to Keppel Harbour than the Battery at Siloso; Rather than mount a third at Siloso, we would prefer to retain the Battery at Labrador, if finance and manning considerations permit.”
In the end, the third gun for Fort Siloso did not materialise, and a two gun 6 Inch Battery was built at Labrador.
The sub-surface power house was modified for oil powered generators, and the subsurface area was enlarged. The enlarged complex led to a staircase leading down to Siloso Point, the old Malay name for which was ‘Sarang Rimau’ or ‘Tiger's Lair’ as tigers were said to have once roamed this area. The complex now consisted of; an oil store, watch room, engine room, observation post and stores.
At Siloso Point, major constructed began for a Twin 6 Pounder Gun to be mounted here. This involved the construction of the emplacement, a Director Tower, Magazine, and three searchlight emplacements. The new searchlight posts were constructed on stilts on the beach at Siloso Point, and were accessed by ladders from Siloso Point. By this time, Electric Lights renamed as CASLs (Coast Artillery Searchlights). Two of the three new ones had a fixed angle beam of 30°, and the third, to south, a fixed angle beam of 45°. These three illuminated a wide area of water, ideal for when engaging fast moving small craft for the 12 Pounder. There were also three 30° CASLs at Batu Berlayar, and a single 30° CASL on Pulau Hantu (Pulau Keppel). All of these CASLs provided an excellent are of illumination for the entrance to the harbour. The two existing CASLs were Fighting Lights for the 6 Inch Guns. These had a narrow beam of 3°. The CASLs were controlled from the second top floor of the Director Tower, and range finding from the top floor. Siloso Point became known as the OSO AMTB Battery.
However, when the defences were completed, no Twin 6 Pounders were available for use at the Fort, although some were mounted elsewhere in Singapore (a Twin 6 Pounder was mounted at Siloso Point after the war).
In the years leading up to the Second World War, a daily exercise was conducted at Siloso Point. Every day, a ‘water boat’ passed through the harbour entrance between Siloso and Tanjong Berlayar. This boat, delivering water to outposts, was tracked, targeted and ‘sunk’ by the Siloso guns.
Elsewhere on Blakang Mati, Forts Connaught and Serapong were also being improved and their armament up-rated. The 9·2 Inch BL Gun on Mount Imbiah was removed and the emplacement was converted for other purposes, and to act as a Reserve Magazine. Pill-boxes and gun shelters were constructed at various places on Blakang Mati to cover the beaches. By 1941, the defences of Blakang Mati had been completed.
In 1939, with the exception of the Buona Vista 15 Inch Battery and the No.1 15 Inch Gun Gun (southernmost) of the Johore Battery at Changi, all the guns were capable of all-round traverse. However when the war with Japan broke out, with the exception of Changi and Sphinx Batteries, concrete overhead splinter covers had been constructed at the Singapore 6 Inch Batteries to provide additional shelter for the gunners. The concrete overhead covers had the effect of reducing the arc of fire of the guns. Sphinx Battery and Changi Battery, still only had their gun shields. Both were due to have splinter covers installed, but when war broke out, the installation was postponed. Covers were also constructed at the Pengerang Battery.
On the 8th December 1941, the Japanese landed at Kota Bahru in northern Malaya at 0215 Tokyo time (one hour and ten minutes before their strike at Pearl Harbor). Singapore had ready to deter a sea borne assault, a powerful coastal artillery defence system under the command of Brigadier A.D. Curtis, the Commander Fixed Defences.
Twelve Coastal Batteries (Fixed Defences) were on Singapore, Pulau Brani, Blakang Mati and Pulau Tekong. On the Malayan mainland at Pengerang to the south east of Pulau Tekong, was another gun battery. There were also several AMTB (Anti-motor Torpedo Boat) Batteries at strategic locations. Many airfields were spread throughout Malaya, and in Singapore there were airfields at Tengah, Sembawang, Seletar and Kallang. Unfortunately, the RAF had precious few aircraft, and none of them modern front-line fighters. Some of the Malayan airfields had no aircraft at all.
Note: Some history books show an airfield at Changi. This is incorrect. The first airfield at Changi was constructed by POW labour under the Japanese. Construction began in 1943.
Faber Fire Command (7th Coast Artillery Regiment) controlled the Pasir Laba, Buona Vista, Labrador, Siloso, Connaught, Serapong, and Silingsing Batteries. Changi Fire Command (9th Coast Artillery Regiment) controlled Johore, Beting Kusah, Changi, Sphinx, Tekong and Pengerang Batteries.
There were infantry and field artillery regiments spread through Malaya and Singapore, with a battalion of infantry in Sarawak. The infantry were desperately lacking in numbers and training, and there were no tanks. More troops had been recommended more than once to bolster the defences of Singapore and Malaya. Tanks were also seen as essential by those who knew that they could be effective in Malaya. The Commander in Chief Air Chief Marshal Sir Robert Brooke-Popham, probably at the behest of Lt. Gen. Percival, even asked for old tanks for airfield defence (left). None were forthcoming until the very last days of the siege of Singapore, when one or two were unloaded from the last convoy arriving. It is not known if these went into action. Too little, and far too late.
To cap it all, the north of Singapore Island had very little in the way of defensive works. Successive British Governments and the War Office in London, had for years ignored recommendations and refused money for strong defences in the north of the island, and in Malaya to be built up. They had a blinkered outlook on defence against an attack from the north, and despite warnings that Malaya and Singapore were vulnerable to such attack, would not accept that any such attack could happen. But come it did, and by the end of January 1942, the Japanese were at the gates of Singapore.
The British Prime Minister, Winston Churchill later said the he had, “No more thought of Singapore having no northern defences than of a battleship being launched without a bottom”. In saying this he, at the very least, misled Parliament and the people. When he was Chancellor of the Exchequer, he drastically cut Singapore’s defence budget, thus preventing essential defence works being carried out. He also clearly knew about the parlous state of the defences against attack from the north, having been warned about them more than once. A Memorandum from the Chief of the Imperial General Staff, dated June 1940, entitled ‘The Security of Singapore’ stated:-
“Developments in Europe which have reduced the availability of an adequate British force for the Far East, combined with a deterioration in Japan’s attitude towards us make the security of Singapore a grave matter” ...... “The Air Forces in Singapore have been reduced from eight squadrons to five squadrons. Even the former figure was short of the pre-war approved scale of air forces, namely twelve squadrons”.
This Memorandum came a month after Churchill became Prime Minister, and it is more than likely that it was brought to his attention.
From 1939 to 1942, The 3rd HKS RA remained at the Fort, along with some British personnel posted there. The CASLs (Coast Artillery Searchlights) were manned by men of the Royal Engineers, both British and Malay.
Singapore Fixed Defences were not called to action until January 1942. Over the years though, some batteries did fire ‘heave-to’ or ‘stopping’ warning shots across the bows of merchant ships straying into the minefields. Some vessels were sunk when they did stray into a minefield.