Royal Australian Navy Station No.9

Myrtletown Boom Defence and Indicator Loop Bunkers

Brisbane City

Myrtletown Reserve, 65 Sandmere Road (end of Gannon Road), Pinkenba 4008

In early 1942, the site initially comprised a machine gun emplacement on the Brisbane River’s north bank built to cover the anti-submarine boom that stretched across the river to Fort Lytton. From February 1943, a submarine indicator loop was added to Pinkenba’s defences. In September 1943, a Photo-Electric Beam Receiver Station was added. The site was designated RAN Station No.9 in January 1944.


In early 1942, the Commonwealth approved the laying of an anti-submarine boom near the mouth of the Brisbane River. The boom was lodged at Bulwer Island (Pinkenba) on the river’s north bank and the boom net ran across to Fort Lytton on the south bank. At Pinkenba, an emplacement mounting a .303 Vickers machine gun was constructed on Bulwer Island. This north bank machine gun nest supported the boom’s main defences that were located across the river at Fort Lytton.

By April 1942, Brisbane had become, along with Fremantle in Western Australia, the major USN submarine bases in the South West Pacific Area. To counter an enemy attack upon the New Farm submarine base, the defences of the Brisbane River were strengthened. A site was chosen downriver from the boom net and closer to the river mouth providing advance warning of approaching shipping on 3 February 1943. A submarine indicator loop was laid across the river from Myrtletown (Pinkenba) on the north bank to Fisherman Island on the south bank. Initially, the site was called RAN Boom Defence Depot, Pinkenba. It was located next to existing shipping berths and a 1,400 feet sea wall.

On 28 September 1943, a Photo-Electric Beam station was added to the defences. A Photo-Electric Beam was transmitted from Fisherman Island to the Myrtletown Receiver Station. The Photo-Electric Beam was a beam of light sent out to the river’s entrance. If the beam detected a ship then it caused a break in a photoelectric cell, triggering an alarm at the Myrtletown Receiver Station. The receiver station (or control room) was a concrete bunker with a separate concrete engine room with timber accommodation huts for officers and other ranks plus latrines, showers and a laundry at the rear. A 12-month expansion program followed that saw the clearing of nearly 10 acres of swampland.

The site was re-designated RAN Station No.9 on 8 January 1944. By October 1944, it comprised: six well-appointed officer’s cabins (total area covered 80 foot x 24 foot), a petty officers’ quarters (40 foot x 20 foot) and two 60 foot x 20 foot rating’s barracks. The petty officers and ratings had separate Mess Rooms and Kitchens (100 foot x 20 foot). The officers were served in their cabins. An Officer’s Building (50 foot x 12 foot) provided three offices. A Recreation Hut (50 foot x 30 foot) contained a billiards room and canteen. On another part of the site, a triple set of rail tracks extended from the main Pinkenba line allowing stores to be freighted directly onto the concrete floor of the Boom Equipment Store (300 foot x 150 foot). Adjacent was a concrete slab (300 foot x 100 foot) used for boom net making and repairs. There was a workshop (50 foot x 120 foot) holding machinery to undertake other repairs. The concrete slabs were laid by the Qld Main Roads Department. Private contractors W.J. Boland and A.R. Bell constructed the buildings.

The US gave support with a Searchlight Battery located 400 metres to the north east of Station No.9. HMAS Limosa removed the indicator loop on 1 June 1945 before the War’s end. The control and the engine rooms plus some hut foundations remain at Pinkenba.


NA file Series BP262/2, Item 9178, Joint Parliamentary War Expenditure Advisory Committee visit to Queensland, October 1944.

Australia @ War