The Secret Military History of Manly's North Fort Plotting Room

Concealed within coastal bushland at North Head Sanctuary in Manly, the underground Plotting Room is part of North Fort – a historic army base that defended Sydney from the threat of invaders.

By Sydney Harbour Federation Trust

Entrance to Plotting Room at North Fort (North Head Sanctuary, Manly), 25 October 2019 (2019) by Ian Evans, volunteer photographer, Harbour TrustSydney Harbour Federation Trust

Part One: An underground coastal defence bunker

Established in 1936, North Fort is a remnant military complex at North Head Sanctuary in Manly, homeland of Gayamagal People. Strategically placed at the northern entrance to Sydney Harbour, the now-demilitarised fort formed part of a defence system that spanned 300km of coastline during World War II.      

Until 1952, the North Fort Battery featured two 9.2 inch calibre guns. Serviced by a network of underground tunnels, each was capable of firing a distance of 26.4km. Target coordinates were relayed to these heavy weapons from the nearby Plotting Room.

Gunner preparing 9.2 inch gun at North Fort (North Head, Manly) for firing., Eric Charles Johnston (Photographer), 1944, From the collection of: Sydney Harbour Federation Trust
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Rear view of 9.2-inch gun at North Fort Battery being fired during a practice shoot., Unknown, 1939, From the collection of: Sydney Harbour Federation Trust
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Gunner loading a 9.2 inch shell on to a hand trolley at North Fort, North Head, Manly, Eric Charles Johnston (Photographer), 1944, From the collection of: Sydney Harbour Federation Trust
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Located eight metres underground, the concrete-reinforced, bomb-proof Plotting Room is accessible via a camouflaged, shed-like entrance. Despite its name, the structure actually consists of two rooms – the Fortress Plotting Room (FPR) and the smaller Battery Plotting Room (BPR).

Entrance to Plotting Room at North Fort (North Head Sanctuary, Manly), 25 October 2019, Ian Evans, volunteer photographer, Harbour Trust, 2019, From the collection of: Sydney Harbour Federation Trust
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Entrance to Plotting Room at North Fort (North Head Sanctuary, Manly), 25 October 2019, Ian Evans, volunteer photographer, Harbour Trust, 2019, From the collection of: Sydney Harbour Federation Trust
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The Plotting Room was vital to Sydney’s coastal defences during World War II, receiving enemy craft intel from – and sending it to – artillery batteries located along the coast from Port Stephens to Port Kembla, collectively known as Fortress Sydney.

Target course and speed was sent via telephone from observation posts to the Fortress Plotting Room and then onto the Battery Plotting Room, which relayed coordinates to North Fort’s guns.

Australian Women’s Army Service (AWAS) personnel and Plotting Officer, Plotting Room, North Fort at North Head, Manly, Eric Charles Johnston (Photographer), 1944, From the collection of: Sydney Harbour Federation Trust
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Members of the Australian Women's Army Service at the North Head Battery, Sydney Fortress Area., Eric Charles Johnston (Photographer), 1944, From the collection of: Sydney Harbour Federation Trust
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The Battery Observation Post at North Fort, North Head, Manly, Eric Charles Johnston (Photographer), 1944, From the collection of: Sydney Harbour Federation Trust
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Australian Women’s Army Service (AWAS) personnel, Plotting Room, North Fort at North Head, Manly (1944) by Eric Charles Johnston (Photographer)Sydney Harbour Federation Trust

Part Two: The Australian Women’s Army Service

In August 1941, the Australian Women’s Army Service (AWAS) began filling key wartime positions at North Head (including the Plotting Room) after being authorised by the government to “release men from certain military duties for employment in fighting units”.    

A member of the AWAS with a connection to the Harbour Trust was the late Patricia Talberg. In 1942, aged 19, she enlisted with the AWAS and was posted to North Fort. As an instrument operator specialist, Patricia manned the observation posts as well as the Plotting Room.

We never fired a shot in anger but daily had to be prepared for it… those few years in the army were richly rewarding. It was a purposeful life, and we made friendships for life. – Patrica Talberg (c. 1989-1990)

Today, Patricia's son Glyn proudly volunteers at the Harbour Trust’s North Fort Visitor Centre, where he greets people and offers them useful tips for exploring the historic site.

Australian Women’s Army Service (AWAS) personnel, Plotting Room, North Fort at North Head, Manly (1944) by Eric Charles Johnston (Photographer)Sydney Harbour Federation Trust

This photo, taken in January 1944, shows members of AWAS working inside the Fortress Plotting Room.

The two standing operators, on the far left, are on bearing arms and have telephone connections to observation posts.

One of the operators lying on the chart is calling out target coordinates, while the other is calling out target course and speed to be relayed to the Battery Plotting Room.

The two operators on right included the Number One of the plotter and the reserve operator.

Four of the women pictured have been identified as Joan Betty Cunneen, Miriam Kohn, Evelyn Barnett Cole and Joyce Eileen Carne.

Although the young men and women who ran the Plotting Room were crucial to the Allied war effort, their story was not made public due to the highly classified nature of their service. In fact, to maintain the veil of secrecy around their work, the Army prohibited photography.

Except for a handful of photos captured by an official photographer in 1944, there is no other significant photographic evidence of the Plotting Room.

Entrance to Plotting Room at North Fort (North Head Sanctuary, Manly), 25 October 2019 (2019) by Ian Evans, volunteer photographer, Harbour TrustSydney Harbour Federation Trust

Part Three: The Plotting Room Restoration Project (2019-20)

Inactive for more than seven decades, the Plotting Room at North Fort has been faithfully restored by a specialist team of 12 Harbour Trust volunteers. 

The restoration project commenced in 2019 and reflects the Harbour Trust’s commitment to preserve, amplify and celebrate the military heritage of its sites on Sydney Harbour. 

Visitors will soon be able to descend into the Plotting Room – a rare example of an intact support building for Fortress Sydney – and discover the military secrets of this heritage bunker as part of a tour guided by volunteers including history buffs and former service people.

Camoflauge -painted pathway, North Fort, North Head Sanctuary, Manly (2020, Ian Evans, volunteer photographer, Harbour Trust, 2020, From the collection of: Sydney Harbour Federation Trust
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Underground tunnel, North Fort, North Head Sanctuary, Manly (2020), Ian Evans, volunteer photographer, Harbour Trust, 2020, From the collection of: Sydney Harbour Federation Trust
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Tour of North Fort, North Head Sanctuary, Manly, 27 November 2018, Ian Evans, volunteer photographer, Harbour Trust, 2017, From the collection of: Sydney Harbour Federation Trust
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The challenge faced by the restoration workers was threefold...

Firstly, the Plotting Room is comprised of confined spaces eight metres underground with no natural light source. As such, the facility had to be made safe for people before the works could start.

Secondly, the Plotting Room was decommissioned after World War II and – during the decades of neglect that followed – the facility fell into disrepair.

Due to years of water damage, feral animals and general wear and tear, parts of the original infrastructure were beyond repair and had to be removed. Consequently, the restoration workers were required to source replacement materials that, as far as possible, closely matched the original fabric of the facility.

Plotting Room at North Fort, North Head Sanctuary, Manly, July 2011, Unknown photographer, Harbour Trust, 2011, From the collection of: Sydney Harbour Federation Trust
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Plotting Room at North Fort, North Head Sanctuary, Manly, July 2011, Unknown photographer, Harbour Trust, 2011, From the collection of: Sydney Harbour Federation Trust
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The Plotting Room in a state of disrepair (July 2011)

Thirdly, many of the Plotting Room’s original fixtures – for example, the plotting table, furniture, light fittings and pinboard wall cladding – had been removed when the building was vacated. Compounding this challenge was the fact that only limited information about the facility’s original set-up existed. As such, the few existing archival images were invaluable to the restoration workers.

Restoration work on Plotting Room at North Fort, North Head Sanctuary, Manly, 25 October 2019, Ian Evans, volunteer photographer, Harbour Trust, 2019, From the collection of: Sydney Harbour Federation Trust
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Restoration work on Plotting Room at North Fort, North Head Sanctuary, Manly, 25 October 2019, Ian Evans, volunteer photographer, Harbour Trust, 2019, From the collection of: Sydney Harbour Federation Trust
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Progress on the restoration project including volunteers at work

Entrance to Plotting Room at North Fort (North Head Sanctuary, Manly), 25 October 2019, Ian Evans, volunteer photographer, Harbour Trust, 2019, From the collection of: Sydney Harbour Federation Trust
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Close-up of Fortress Plotting Room (following volunteer restoration works), September 2020, Ian Evans, volunteer photographer, Harbour Trust, 2020, From the collection of: Sydney Harbour Federation Trust
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Battery Plotting Room (following volunteer restoration works), September 2020, Ian Evans, volunteer photographer, Harbour Trust, 2020, From the collection of: Sydney Harbour Federation Trust
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The Plotting Room entrance, Fortress Plotting Room and Battery Plotting Room

To the extent possible, the original fabrics and fixtures of the Plotting Room, including the framing for the ceiling, were retained and stabilised by the workers. Where the original components couldn’t be salvaged or were missing, historical references were used to create faithful replicas.

These include the pinboard wall coverings, office area windows, metal fittings and the all-important plotting room tables. Further, the workers restored a World War II era ratemeter, reinstated the underground ventilation system, and painted a camouflage pattern on the exterior to enhance the visitor experience.

Plotting Room Restoration Team assembled in the Fortress Plotting Room, September 2020 (2020) by Ian Evans, volunteer photographer, Harbour TrustSydney Harbour Federation Trust

Plotting Room Restoration Team

Plotting Room Restoration Team members discussing thepinboard wall covering, September 2020 (2020) by Ian Evans, volunteer photographer, Harbour TrustSydney Harbour Federation Trust

Despite the challenges, the Plotting Room Restoration Project was a labour of love... 

Plotting Room Restoration Volunteer observing a replica plotting table, September 2020 (2020) by Ian Evans, volunteer photographer, Harbour TrustSydney Harbour Federation Trust

The specialist restoration workers were able to harness their skills as engineers, tradespeople and handymen to preserve a significant slice of military history.

Plotting Room Restoration Team members discussing the plotting table, September 2020 (2020) by Ian Evans, volunteer photographer, Harbour TrustSydney Harbour Federation Trust

The Plotting Room project is part of a broader effort by the Harbour Trust to restore North Fort. Most recently, 18 restoration workers recreated North Fort’s underground engine room, which powered two 9.2 inch guns during World War II. Their work involved repairs to the engines, power distribution board and cooling tanks. In helping us preserve the site’s defence history, these specialist volunteers have also enhanced the guided tour experience for visitors.

Members of the 7th Battalion, Volunteer Defence Corps, The Battery Power House at North Fort, North Head, Manly, Unknown, From the collection of: Sydney Harbour Federation Trust
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Engine Room of North Fort, North Head Sanctuary, Manly (2020), Ian Evans, volunteer photographer, Harbour Trust, 2020, From the collection of: Sydney Harbour Federation Trust
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North Fort's underground engine room during World War II and today

Enjoy this video demystifying The Plotting Room and showcasing the efforts by specialist volunteers to faithfully restore it...

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