| Historical notes: | Prior to the entry of Japan into World War Two in early December 1941 it was the policy of Military Command in New South Wales to give priority to the fortification of the industrial areas of Newcastle, Sydney and Port Kembla. However, Japan's rapid advance and it's attack on Malaya and Pearl Harbor, saw the decision made that certain country areas also needed defensive measures in the event of an air attack, including Lithgow and Bathurst. In addition, bridges and roads were identified for destruction, road blocks and obstacles were erected in northern suburban areas of Sydney, tank traps were constructed and a variety of activities undertaken to prevent a land based enemy invasion reaching the inland areas. Lithgow was included as an adjunct to the Sydney Fortress Area in order to place its industries, transport infrastructure and defence site under protection from aerial attack, including the Small Arms Factory in the centre of Lithgow, the ammunition depots at Clarence and other railway tunnels, the major Depot at Marangaroo and the various coal mines in the Lithgow Valley and nearby. Sydney Command was particularly concerned about attack from the high level Japanese bombers and low level strafing fighter planes or dive bombers. The Army Command inspection of December recommended the defences take the form of two 4 gun 3.7 inch anti-aircraft batteries plus a Lewis Machine Gun detachment for the close defence of the Lithgow Small Arms Factory. The Small Arms Factory had been constructed as a central defence arsenal between 1909 and 1911 as part of Australia's general movement towards self sufficiency following Federation in 1901. This movement saw greater desire to manufacture and grow food, supplies and other needs at home rather than buying them from overseas. (Southall, 1995: 7-9; Robertson & Hindmarsh, 2006:66-94)
The Army concluded that any aerial attack on the Lithgow area would, because of the topography of the Lithgow Valley, be from either end of the valley rather than across the narrow valley. This dictated the placement of one Heavy Anti Aircraft Gun Station (A Troop) at the western end of the valley at South Bowenfels and the other Heavy Anti Aircraft Gun Station (B Troop) at the eastern end of the valley on the heights of Scenic Hill overlooking the Vale of Clwydd. A third detachment was to be mounted on the roof of the Small Arms Factory using a Lewis Machine Gun for the close defence of the factory and to provide protection against strafing fighters and from dive bombers.
Work began on the stations immediately and workmen from the Water Conservation and Irrigation Commission poured the concrete floors of the emplacements prior to 22 December 1941. The emplacements were ready to receive and mount the guns on their hold-down bolts on that date. The urgency for completion of the gun stations increased as the Japanese moved through Malaya, Singapore and finally to various islands north of Australia. As a result, no time was allocated to allow the concrete to cure. However the original guns intended for Lithgow were sent to Singapore and remained on the docks there until captured by the Japanese in 1942. This delayed the delivery of the guns to the last week of 1941. The Clwydd guns were not installed until 2 January 1942. The guns at the Bowenfels Gun Station were installed soon after. The guns were protected by temporary sand bag revetments until the reinforced concrete and brick revetments were constructed. These revetments also became the ammunition/storage bays and were designed to protect the gunners from bomb blasts.
The Command Posts at both batteries were the next items to be constructed. The Command Post was centrally located among the four gun emplacements and was, according to Southall, of a World War 1 blockhouse design. From the central room of the blockhouse protected passages gave access to the platforms containing the tracking instruments: the Predictor on the roof of the octagonal section of the Command Post and the Barr & Stroud Height Range Finder and the Telescope (or Toc 1). All the platforms were protected with removable roofs which could swing open on hinges ready for action.
The Predictor, manned by 6 gunners, was manufactured by Vickers in England and was the equivalent of a computer which determined the direction and speed of travel of the enemy aircraft and the time of flight for the projectile fuse setting. This information was transmitted by coaxial cable to each of the four guns in the battery. Whilst the Predictor may have been a primitive computer it had to be kept on target visually by one operator following the 'line' and the other the 'elevation' (Southall, 1995: 10-1; Browning, 2010).
The gun stations were connected to the Headquarters in the Lithgow Drill Hall. Both were operational by the end of January 1942. Dummy gun emplacements, farms and other facilties were established around them.
The threat to Australia moved further north and the guns were removed during December 1943 and January 1944. The guns and their artillery crews are believed to have been shipped to islands off the northern coast of Australia. (Lithgow Mercury, 2003:1) The "hoax farm" buildings were auctioned off after 1945.
In 2003 three anti-aircraft guns of the type originally located at South Bowenfels and Scenic Hill were installed at Bowenfels, following their restoration. Works were then completed around the gun emplacements to facilitate public access to the site. (Lithgow Mercury, 2003:1)
ANTI AIRCRAFT GUN STATION SITES
There were over 100 static Anti Aircraft Gun Station sites for defence against air attack were established in Australia during World War Two. Approximately thirty were established in NSW, primarily along the coast between Port Kembla and Newcastle. By the end of 1940 Sydney had 36 anti-aircraft guns and a variety of other guns. Newcastle had 28 Anti-Aircraft guns and six others. Numerous additional guns had been added by 1943. Guns, searchlights and other facilities were located at places including Bankstown, Clemton Park, Beverly Hills, Moore Park, Rathmines North Stockton and Nobbys Head (Newcastle), and Port Kembla (Wollongong). Inland, east of the Blue Mountains, facilities were located at Freeman's Reach and Clarenden near Richmond. The Anti Aircraft sites at Lithgow were the only sites located west of the Blue Mountains (Robertson & Hindmarsh Vol 2, 2004-2006: 73-74)
THE ROLE OF HEAVY ANTI AIRCRAFT ARTILLERY (K.Browning, July 2010)
The primary role of HAA artillery is defence against hostile aircraft flying at a height up to 35,000 ft (10,700 metres). During World War II the accuracy of bombing was limited to the skill of the aircrew and the higher the bombers were flying the less likely they would hit their target.
The main equipment of the Heavy Anti Aircraft artillery was the 3.7 inch Anti Aircraft gun which came in two versions, static and mobile. The main difference between the two types of gun was that the mobile has the outrigger legs and the static was bolted to the ground and had a large arm atop to counter the weight of the barrel being slightly further forward of the point of balance. It is believed that approximately 50 mobile units are known to survive in Australia. Only two static guns are known to remain.
The gun fired a 49 lb (22.2 kg) 3.7 inch (94 mm) round (shell weight 28 lb (12.7 kg) to an effective height of 25,000 ft (7,600 metres). The muzzle velocity was 2,670 ft/sec (814 m/sec). Maximum rate of fire was between 12 and 15 per minute.
The manning of units varied throughout the war but basically they consisted of a 4 gun sub-unit with command post. HAA guns were sited in fours, with a multi core cable from the predictor to each gun. This cable operated two dials (bearing and elevation) on the gun, and with time fuses, a fuse dial, each with an operator matching pointers.
The Command Post (CP) was manned by a Lieutenant, Gun Position Officer (GPO); a Sergeant, Gun Position Officer Assistant (GPOA); a telescope identification (TI) operator; a height finder (UB7) manned by three men; and the predictor manned by six men including a bombardier.
Each static gun had 11 personnel; one sergeant, one bombardier, nine gunners. Mobile guns had 9; the difference was that the static gun needed two men to load the shell, as the gun was too high for the method used with the mobiles, where a gunner punched the shell into the breach. The guns were located in revetments built to trunnion height and laid out in a shallow arc of about 90 degrees close to and easily seen from the Command Post.
At the end of World War Two all static guns were removed and only the mobile versions retained. Although Australia produced 600 static 3.7 inch guns of the type originally located at Lithgow, only two are known to remain today. Both are located at North Fort on North Head in Sydney. Surviving mobile guns at South Bowenfels are considered the largest collection of their type in NSW. |