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Fort Forrest Fremantle
Built between 1907 and 1908, Fort Forrest in North Fremantle was part of the first major coastal defence system protecting Fremantle Harbour after Federation. The battery stood on the north side of the harbour entrance at North Fremantle, close to where the Commonwealth Oil Refineries fuel depot was later built.
At the time, Fremantle had recently become Western Australia’s main port, following the official opening of the Inner Harbour on 4 May 1897. Once the harbour opened, it immediately became a strategic economic gateway. Ships carrying goods, mail and passengers to and from the State all passed through the narrow entrance between the North Mole and South Mole breakwaters. Because every vessel entering the port had to pass through this single channel, it created an obvious choke point that could be defended.
After Federation in 1901, responsibility for defence shifted from the individual colonies to the newly formed Commonwealth Government. Major ports such as Fremantle were now considered national strategic assets and planning began for a network of coastal artillery batteries to protect them against possible naval attack.
The concern at the time was not that a foreign power would invade the colony, but that enemy cruisers might attack shipping, bombard port facilities or disrupt trade during a war involving Britain and its allies. Fremantle was considered particularly important because it was the State’s primary naval and merchant port, a refuelling stop for ships travelling through the Indian Ocean and a potential target for commerce raiders attempting to disrupt British and Dominion shipping routes. Ships using this route typically travelled from Britain through the Mediterranean and the Suez Canal, across the Indian Ocean to Fremantle, before continuing to Adelaide, Melbourne, Sydney and New Zealand.
Fort Forrest was constructed as part of a defensive system guarding the harbour entrance. It worked alongside other positions such as Arthur Head on the southern side of the port and later the batteries built on Rottnest Island.
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Entering Fremantle Harbour (1905)
Construction and design
Exact construction costs for Fort Forrest alone are difficult to distinguish because it formed part of the wider Fremantle coastal defence programme. Comparable coastal batteries built during the same scheme were estimated to cost around £11,600 for a standard layout including gun emplacements, ammunition magazines, observation posts and supporting stores. Based on this, the Fort Forrest installation probably cost somewhere in the range of £10,000 to £15,000, which would equate to several million dollars in modern currency depending on how inflation is calculated.
Construction was overseen by the Commonwealth Department of Defence with engineering work carried out by the Royal Australian Engineers and local contractors supplying excavation and concrete works.
Before the battery was built, the area at North Fremantle consisted mainly of coastal dunes and limestone ground. Like much of the harbour entrance, the land had been retained as Crown reserve for harbour and defence purposes.
A completed battery typically included:
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two gun emplacements
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underground ammunition magazines
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shell and artillery stores
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observation and range finding positions
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communication links to the harbour defence network.
Personnel were primarily housed at the Victoria Barracks (also known as the Fremantle Artillery Barracks) on Burt Street, which was constructed between 1910 and 1913 to support the harbour defence system.
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Fort Forrest Fremantle and the Defence of Western Australia (1916)
Guns and equipment
Fort Forrest was equipped with two BL 6-inch Mk VII breech-loading naval guns, a type widely used throughout the British Empire for coastal defence.
These guns fired shells weighing roughly 100 pounds (≈ 45 kg) and had a maximum range of 13 to 14 kilometres, depending on charge and elevation. Their job was to engage hostile cruisers approaching Fremantle Harbour or attempting to enter the port.
Breech loading means the gun is loaded from the rear rather than the muzzle. This allowed for faster firing, improved personnel safety and made it easier to operate the gun from protected positions.
The guns were British designed weapons manufactured in the United Kingdom and distributed throughout the Empire for naval and coastal defence use. Range and firing performance were determined using ballistic firing tables developed during testing. In service, range to the target was refined using rangefinders and plotting instruments.
Like many coastal batteries, Fort Forrest relied heavily on supporting systems to make the guns effective. These included telephone lines linking the battery with observation posts and other defence positions, visual signalling systems using flags or lamps and searchlights used at night to illuminate potential targets.
A Defence Electric Light installation was installed on the North Mole in 1911 to support Fort Forrest and Arthur Head, helping coordinate the harbour defence system.
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Group of soldiers in informal dress at Fort Forrest (1915)
Personnel
The guns were manned by the Royal Australian Garrison Artillery (RAGA), the branch of the Australian military responsible for fixed coastal defence batteries.
This organisation emerged from the reorganisation of colonial artillery units after Federation. By 1903, Australia had established an Australian Garrison Artillery branch, which was renamed the Royal Australian Garrison Artillery in 1911. Their role was to operate fixed coastal guns, maintain equipment and carry out the technical work involved in Rangefinding and fire control. Crews spent much of their time training in drills and instrument work, so the guns could be brought into action quickly if required.
In 1927 the garrison artillery and field artillery branches were combined into the Royal Australian Artillery, which continues today.
Defending the harbour
The entrance to Fremantle Harbour is formed by two long breakwaters, built during the harbour works in the 1890s. The North Mole extends south west from North Fremantle, while the South Mole extends north-west from Fremantle itself. Between them lies the narrow channel ships must pass through to reach the Inner Harbour.
Navigation lights at the ends of the two moles mark the sides of this entrance and guide vessels safely between them.
Fort Forrest’s guns were positioned so they could watch and control this approach. Their purpose was to prevent hostile ships from entering the harbour and to deter cruisers from approaching close enough to bombard port facilities.
Defending the port involved several different roles. The batteries provided the firepower needed to stop hostile ships. Observation posts and signalling stations monitored incoming traffic. Communication systems linked the different defence positions together.
Incoming ships were identified using international maritime signalling systems, such as the International Code of Flags. At night, signal lamps using Morse code were often used. In wartime, examination services could challenge ships approaching the harbour, verify their identity and ensure they were authorised to enter.
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International Code of Flags
Limitations of the site
Although Fort Forrest served its purpose during the early years of the harbour defence system, the location had several limitations.
Naval guns on warships rapidly increased in range and accuracy during the early twentieth century. By the 1920s and 1930s, an enemy ship could potentially remain further offshore and bombard port facilities, without entering the effective range of batteries positioned at the harbour entrance.
As a result, defence planners began moving coastal guns to locations where ships could be engaged much earlier in their approach. For Fremantle, this meant strengthening positions further along the coast, including Swanbourne, Buckland Hill (Leighton Battery) and Rottnest Island.
Removal of Fort Forrest
By the mid-1930s, Fort Forrest was becoming obsolete and the land it was occupying had become increasingly valuable for industrial use.
At the same time, the oil industry was rapidly expanding around Fremantle Harbour. Storage tanks belonging to companies such as Anglo Persian Oil and Vacuum Oil (a subsidiary of the Standard Oil Company of New York) were already located nearby and further installations were being proposed. The presence of these tanks raised concerns because large quantities of flammable fuel located close to a defensive battery could be dangerous during wartime. There was also pressure from commercial interests to allow for more oil storage near the port.
In June 1935 the Commonwealth Defence Committee recommended lifting the embargo on further oil installations along the North Fremantle foreshore. The Government decided that Fort Forrest should eventually be removed and the guns relocated to a new site further north, most likely near Swanbourne.
The relocation process proved slow and complicated. Negotiations were required with the Western Australian Government to obtain land for the new battery and maintain defence capability while the guns were being moved.
Plans involved temporarily installing the Fort Forrest guns at Swanbourne on girder mountings while permanent emplacements were constructed. Transporting the heavy equipment required careful planning. The guns and associated equipment had to be moved along the narrow Perth Fremantle highway during the early hours of the morning to minimise disruption to civilian traffic.
By 1937 the Commonwealth had agreed to sell the Fort Forrest site to Commonwealth Oil Refineries Ltd for £9,000, so the company could expand its fuel storage operations. Removal of the battery took longer than expected due to the difficulty of dismantling the heavy structures and transporting the equipment.
The fort was finally dismantled and cleared by August 1937.
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Outdoor group portrait of Permanent Royal Australian Artillery personnel at Fort Forrest (1936)
From fort to fuel depot
The Commonwealth Oil Refineries bulk oil storage installation was constructed on the former Fort Forrest site at North Fremantle. One of the original gun emplacements was retained within the installation boundary as a historical reminder of the earlier defence works.
Because later industrial development covered much of the area, the exact location of the battery is sometimes confused with nearby oil storage sites in historical references.
Naming of the fort
Fort Forrest was named after Sir John Forrest, a prominent Western Australian explorer and politician.
Forrest began his career as a surveyor in the colonial government and led several major exploration expeditions across Western Australia and South Australia. His achievements in surveying large areas of previously unmapped country earned him the gold medal of the Royal Geographical Society of London. He later entered politics and became Western Australia’s first Premier, when responsible government was introduced in 1890 and held the position for nearly eleven years before moving into federal politics after Federation.
During his national political career he served as Minister for Defence, Minister for Home Affairs, Postmaster General and Treasurer. In 1891 he was knighted, becoming Sir John Forrest. In recognition of his long public service, he was elevated to the British peerage in 1918, becoming the first Australian to receive that honour. A British peerage is a noble title granted by the monarch, such as Baron or Earl, that makes someone part of the British nobility.
Sir John Forrest died at sea on 4 September 1918 while travelling to England.
The former site of Fort Forrest after demolition of the Caltex–Viva Energy oil tanks (2021)
