Fort Cowan Cowan

Royal Australian Navy Station No.3


25 Dorothy Newnham Street, Cowan Cowan 4025


Island developed into the major component of the World War Two coastal defences of Brisbane. In 1939, the island had just the Cowan Battery, one of only two forts protecting Brisbane. During the war, the island was the Examination Battery and War Signal Station for the port of Brisbane. It was reinforced with a second battery of coastal guns, an army battalion and an armed RAN auxiliary warship. The island also utilised the services of the CCC, the VDC and three separate RAN Station units that controlled a variety of Moreton Bay defences, including minefields, submarine indicator loops and Asdic Detectors.



Island shields the northern entrance to Moreton Bay. Three major shipping channels that lead to the mouth of the Brisbane River and onto the port of Brisbane run past the island - North West Channel, North East Channel and South Passage.

In 1938, a battery of two 6-inch Mk II coastal guns mounted on PV1A carriages and supported by two 90 cm searchlights were emplaced on the Moreton Bay side of the island. The Cowan Battery was constructed with reinforced concrete. The ammunition magazines were built to the rear of each gun platform. Side blast walls and a concrete roof were added later. Concreted battery observation and command posts, gun stores, engine house and searchlight emplacements were built. The barracks, orderly rooms, latrines, ablution huts, casualty dressing station, operating ward and post office were of timber and corrugated iron.

At the outbreak of war in 1939, the 2/2nd Garrison Battalion sent troops to defend Cowan Battery. The island’s commandant was the battalion’s commander Lieutenant Colonel Lamb. Lamb had no operational control of the battery. Major Rodney Morrell (Royal Australian Artillery) was the battery commander. Cowan Battery was declared the Examination Battery for the port of Brisbane On 2 September 1939, the tug HMAS Otter (271 tons) was requisitioned and sent to Cowan Battery as the examination vessel. The old (1882) Otter was paid off on 20 December 1940 and replaced with other requisitioned Brisbane vessels. The Port War Signal Station was initially established at the Cowan Battery but it was moved to Caloundra in 1942.

By January 1942, an (World War One era) 18-pounder field gun plus a 2-pounder anti-tank gun were put at Honeymoon Bay and weapons pits dug by the 2/2nd Garrison Battalion. These were Moreton Island’s beach defences to meet any Japanese amphibious assault. On 4 March 1942, due to a mix-up of naval code signals, Fort Cowan fired a warning shot at the auxiliary minesweeper HMAS Tamar (456 tons). The shell was meant pass across the bow but it hit Tamar. Two sailors were killed while a third died at Greenslopes 112th Army General Hospital. After repairs, Tamar was converted to an auxiliary boom defence vessel.

A submarine indicator loop (cable) was laid between Comboyuro on Moreton Island and Woorim on Bribie Island by mid-November 1942. To control the indicator loop off Moreton Island, RAN Station No.7 was based at Comboyuro. In late 1942, three harbour defence Asdic Detectors were placed to the south of the indicator loops. The Asdics gave an underwater supersonic bearing for a range of one mile on approaching vessels and was more accurate than the indicator loops. RAN Station No.2 at Tangalooma on Moreton Island controlled the Asdics as well as acting as the mine de-gaussing station for the port of Brisbane.

During 1942, minefields were laid in the main Moreton Bay shipping lane at three locations - off Cowan Cowan Point and in Pearl and the North West Channels. The minefields were laid on the seabed, in rows of four and were wired to a BOP of a main control station. RAN Station No.3 was established near Fort Cowan to control the Moreton Bay minefields. While the RAN manned the underground control bunker and maintained the minefields, it was the responsibility of the Cowan Battery commander to fire any mines.

Japanese submarine activity off Brisbane was first reported on 24 March 1942, when a RAAF No.23 Squadron Wirraway from Archerfield dropped two bombs on a submarine off Stradbroke Island. The passenger ship Canberra reported the sighting of Japanese submarine I-29 off Moreton Island on 4 June 1942. On 8 March 1943, the corvette HMAS Wagga (2,000 tons) depth-charged a submarine off Southport. The decision was made to emplace another battery on the Pacific Ocean side of Moreton Island to cover the South Passage. Construction commenced around February 1943 at Toompani Beach. The Civil Construction Corps (CCC) bulldozed the 'Tangalooma Track' across the island to the Beach and established a temporary onsite work camp. The gun and searchlight emplacements, magazines, underground plotting room, battery observation post (BOP) and water tank of the Rous Battery were nearly completed when the ‘O’ Heavy Battery unit under Major R.K. Fullford arrived in March.

‘O’ Battery built a camp behind the hilltop BOP. It comprised tents and a corrugated iron kitchen hut. The gunners also laid telephone lines and made their tents more comfortable through the use of local bush timber. Lieutenant Ward, the duty officer for the gun-less Rous Battery saw a glow on the eastern horizon on 14 May 1943 that came from the sinking of the hospital ship Centuar by the submarine I-177. Two 155 mm M1918A1 guns with two 150 cm Sperry searchlights with electric/petrol generators finally reached the island in June and were emplaced by July. Rous Battery had mainly US equipment of a plotting table, two Azimuth instruments (observation & tracking) plus a British Mk V depression range finder. The 2/2nd Garrison Battalion again provided beach defences, while camouflage and several light machine guns comprised the anti-aircraft measures. In August 1943, ‘O’ Battery was withdrawn and replaced by ‘G’ Heavy Battery. That same year, Volunteer Defence Corps members began to replace the RAA gunners manning Cowan Battery.

In late 1942, construction of a submarine barrier blocking Rous Channel between Reeder’s Point on Moreton Island and Amity Point on Stradbroke Island began. The barrier comprised 3-foot squares of steel wire mesh hung between groups of timber dolphins. The tidal race in the Rous Channel severely hampered work and the barrier was not finished until 1945.

At the end of the war, Rous Battery, the minefields, indicator loops and submarine barrier were removed. Cowan Battery was disarmed in 1955.


National Archives of Australia - Series, J3024, AWM52, MP729/6, Mp150/1

Dunn, P. Cowan Battery, at Cowan Cowan, Moreton Island Australia @ War website.