Fort Bribie

Fortifications
South-East

North eastern aspect of Island, Bribie Island 4507

Fort Bribie, constructed between 1940 and 1942, consisted of two 6-inch guns and their support infrastructure, and was designed to defend the North West Channel into Moreton Bay. The northern searchlight emplacement is about 24.5 km by 4WD from the car park at the north end of North Street, Woorim. The fort is also linked to the Ocean Beach camping ground by a walkway.

Beach erosion is gradually exposing more elements of the fort over time. The main surviving concrete elements include the northern searchlight, a two storey structure now standing on the beach. The northern (Number 2) gun emplacement is about 640m south of the northern searchlight, while an observation structure is located about 425m south of the northern searchlight. The observation structure consists of two walls supporting a platform above with a partial wall. About 30m to the south is the buried northern Mine Control Hut, and then the larger southern Mine Control Hut. Recently, concrete and steel remains of another structure were revealed by beach erosion about 60m south of the southern mine hut.

About 160m to the south of the mine huts is the northern gun emplacement, a two storey structure with a gun platform open to the east and five rooms below. The concrete and timber overhead cover for the gun has collapsed. There is over 100m distance between the gun emplacements. The southern (Number 1) gun emplacement retains its overhead cover. About 60m south of the Number 1 gun is the Signals Operations Room (SOR), which was once buried in a sand dune, but is now exposed on the beach.

In the area to the west and south of the SOR are a number of concrete slabs and concrete stumps for various camp buildings. Other concrete structures survive around the camp area, including several round wells, urinals, pump house, septic tank, and septic pipeline mountings. Little remains of the Command Post (CP) at the south end of the men’s section of the camp.

The most southern element is another searchlight, located close to the beach about 620m south of the Number 1 gun emplacement.

History

Prior to the emplacement of two 6-inch guns at Cowan Cowan on the West side of Moreton Island in 1937, the coastal defence of the Moreton Bay region was based at the mouth of the Brisbane River at Fort Lytton, constructed in the 1880s.

The above defences were supplemented after the outbreak of World War II in September 1939, when two 6-inch Mk XI guns (8th Heavy Battery) were positioned at the north end of Bribie Island. The guns were installed by March 1940, but their temporary steel cruciform mounts were unstable and sand dunes blocked their field of fire.

In July 1940 there was only a timber control tower, the magazines had no floors and there were no searchlight emplacements, but in February 1941 plans were being developed to upgrade Fort Bribie, with additional camp huts, two gun emplacements, a Battery Observation Post (BOP), Command Post (CP), Observation Post (OP) and two DEL (Defence Electric Lights, also known as CASL, or Coastal Artillery Searchlights). In March 1941 Colonel JS Whitelaw, Commander Coast Defences, Eastern Command, recommended building a BOP about 200 yards north of the northern gun; a CP about 200 yards south of the southern gun, and a plotting room halfway between the northern gun and the BOP. Fort Bribie’s role was to provide close defence of the North West Channel into Moreton Bay.

The entry of Japan into the war on 7 December 1941 no doubt spurred efforts to upgrade Fort Bribie, and also to increase the infantry defence of the island. An inspection of Fort Bribie in February 1942 noted that a good hutted camp existed at the fort, complete with showers, latrines and a very fine kitchen and refrigerator. However, the power supply and a lack of water were problems. A canteen and Post Office were being constructed, and the 'technical' (BOP etc) buildings were all in a partially finished state.

Other units on the island at the time of this inspection included a Garrison Battalion, an AIF Composite Company, and a Militia Battalion. Volunteer Defence Corps (VDC) personnel also helped with construction work on the island. The AIF Composite Company had a number of machine gun positions north and south of Fort Bribie, plus two mortar positions and two timber pillboxes south of Fort Bribie, by 31 December 1941. Mosquitoes, sandflies and fleas proved to be a major irritant for all personnel stationed on Bribie. In addition to the infantry, the Australian Women’s Army Service (AWAS) arrived in 1943, and were involved in most aspects at Fort Bribie except the manning of the guns. Their huts were located south of the Officer’s Mess and the CP.

Construction of the new two storey gun emplacements, two storey searchlight emplacements, BOP, CP and Plotting Room at Fort Bribie was completed by April 1942. Later that year two American 155mm guns were stationed at Skirmish Point at the south end of Bribie Island, and in 1943 a similar battery was positioned at Rous, on the east side of Moreton Island.

Within Fort Bribie are the two Mine Control Huts used by Royal Australian Navy (RAN) Station 2 during 1942 and 1943. These controlled “guard” indicator loops and mine loops set in the North West Channel. An Indicator loop relies on the production of an induced current in a stationary loop of wire when a magnet moves overhead, and when a submarine was detected by the guard loop, the operator would wait until there was also a galvanometer 'swing' on the mine loop and then the mines would be detonated from the Mine Control Huts, by sending a current down the mine loop. The Mine Control Huts have no windows, so observation of the ocean surface (to confirm that a submerged object had been detected) was most likely conducted from the structure located just north of the mine huts.

A 1945 map of Fort Bribie places the CP to the south of the camp (the southern searchlight is off the map), and a Signals Operations Room (SOR) is recorded east of the northernmost section of the camp, south of the southern (Number 1) gun. Reserve magazines are shown west of each gun emplacement. To the north of the northern (Number 2) gun the two Mine Control Huts formerly used by RAN Station 2 are marked as “Magazines", and the structure just to the northeast of these buildings is recorded as a BPR (Battery Plotting Room). Further to the north is a BOP, and beyond that the northern searchlight. An underground hospital, reported to have been built south of the officers’ mess and sleeping quarters, is not marked on this map.

The structure marked as the BPR on the 1945 map has also been referred to by various modern sources as the BOP. In 2009 parts of another structure were discovered just south of the Mine Control Huts, and this has been called the BPR. If the structure just north of the Mine Control huts is the BPR, its distance from the northern gun emplacement is much further than is indicated by the 1945 map. However, it does not match an August 1941 requirement that the BOP be constructed as a steel frame and fibrolite structure with bulletproof plating for the rangefinding cells. For the purposes of this webpage, the concrete structure just north of the Mine Control Huts will be referred to as an observation structure.

Source/comments

Bribie Island Second World War Fortifications, Queensland Heritage Register 601143

RAN Station 9, Pinkenba (Myrtletown), Queensland Heritage Register 601448

Fort Cowan Cowan (Cowan Cowan Battery). Queensland Heritage Register 602559

Donald, Ron, 1995. Fort Bribie. The story of wartime Fort Bribie and Toorbul Point. Bribie Island RSL.

Groves, John. 2006. North Bribie Island during World War II. John Groves, Jimboomba.

Groves, John and Janice. 2007. Digging deeper into North Bribie Island during World War II. John and Janice Groves, Caloundra.

National Archives of Australia, Folder B Folio 39. Fort Bribie Camp Layout - Site Plan [1/B/4]. 1945.

National Archives of Australia, Folder B Folio 40. Bribie (Fort) Camp Layout [plan number 1/B/4], 1945.

National Archives of Australia, 23/402/153. Bribie Island Fortress, 1939–44.

National Archives of Australia, 224/602/24. Bribie Island, Queensland - fixed coast defences, 1941–45.

National Archives of Australia, CD81. Bribie Island fortifications DEL and engine rooms, 1941–43.

Aerial 2004. DERM Ecomaps, QAP6078159.

Walding, R. Fort Bribie and Fort Bribie History

Walding, R. Royal Australian Navy Defences—Fort Bribie. The RAN 2 Controlled Mining Station

Walding, R. Indicator Loops and Coastal Army Fortifications at Moreton Island

Australian War Memorial Photographic Images 044509 and 044511.

Sunshine Coast Libraries photographic image P89827 Fort Bribie coastal artillery personnel, c.1943.

Sunshine Coast Libraries photographic image P89826 AIF mortar post, Bribie Island Dec 1942.

Sunshine Coast Libraries photographic image P89300 BOP Fort Bribie 1946.

Distance measurements by Marianne Taylor, DERM.