HMA Submarine AE2 ‘Silent ANZAC’ protected with Aussie ‘top hat’

27 July 2014 in Defence

23-07-2014 - HMA Submarine AE2 ‘Silent ANZAC’ protected with Aussie ‘top hat’

For the first time in 100 years the World War I Australian submarine, HMAS AE2’s (the Silent ANZAC) conning tower hatch was opened in June 2014. The wreck is intact, sitting upright in 73 meters of water in the Sea of Marmara where it fell in battle on 30 April 1915.  Australian based advanced composite manufacturer and composites specialist, RPC, lent its expertise to develop a secure top hat to be placed over the open conning tower hatch as part of an initiative of the AE2 Commemorative Foundation.  RPC Technologies undertook the work on a pro bono basis, with the design, specialist fabrication and manufacturing being undertaken at its Corio facility.

The ‘top hat’ (hatch), specially designed and manufactured by RPC in glass reinforced plastic (‘GRP’), fits over the open conning tower hatch to prevent unauthorised entry to the submarine. The hatch had to be strong, light and securable to prevent unauthorised entry. It also had to have exceptional anti-corrosion properties to contend with both the rigours and sensitivities of a marine environment at a depth of some 73 metres.

RPC Executive, John O’Brien points to the “impressive strength to weight characteristics of composite materials which made GRP a natural choice for the hatch. GRP also offered the lifelong corrosion resistance needed in an underwater environment as well the strength to properly secure the vessel from unauthorised entry”.

“Composite materials like GRP give us the ability to produce complex shapes to enable multiple components to be moulded into one part which also helps to save on weight and helps reduce manufacturing costs”, says RPC’s James Zegir. “We are fortunate as a Company to have some of the world’s leading composite engineers to draw upon when faced with design challenges like the ‘top hat’”.

There were also special design requirements to shape and provide slots within the new hatch to allow for normal water current flow and to provide unimpeded access for marine creatures.

John O’Brien coordinated the project on behalf of RPC, with their Technical Manager, James Zegir, designing the hatch that was ultimately crafted by RPC employees Floro Cabanban with support from Dave Byrnes and Bill Jones at the Corio facility.

RPC’s 40 years’ experience in advanced manufacturing for water infrastructure, passenger rail and the Australian defence industries were also drawn upon to develop a simple yet effective design.

The ‘Silent ANZAC’ project has been an extraordinarily successful collaboration of experts, all volunteers, drawn from Australia, USA and Turkey


RPC is a leader in the design, engineering and manufacturing of fibre composites and advanced materials.  Specialising in the Defence, Infrastructure, Rail, Oil, Gas and Pipe Systems sectors. 

RPC offers integrated engineered and manufactured solutions from design and delivery to site installation to through-life support.  The company employs 500 skilled employees across Australia and SE Asia and is a trusted partner of the Australian Defence Force.


HMAS AE2, also known as the ‘Silent ANZAC’, was the first Allied submarine to penetrate the Dardanelles strait in 1915 as part of the Gallipoli Campaign, and on the morning the ANZAC soldiers landed at Anzac Cove.

AE2 became the first Royal Australian Navy warship to conduct a torpedo attack against an enemy warship. But after five days she finally fell to Ottoman gunfire and was scuttled.

Her commander, HG ‘Dacre’ Stoker, and crew were captured and spent the rest of the war as prisoners of the Ottoman Empire.

The AE2 lay in the Sea of Marmara, unseen, until 1998 – when she was discovered, intact, 73 metres underwater.

Project Silent ANZAC, an initiative of the AE2 Commemorative Foundation, is about preserving HMAS AE2 where she lies. The Project involves taking steps to limit further corrosion, making sure there is no future damage from shipping movements, fishing trawlers and divers, and ensuring that the hull is secured and monitored by anti-intruder devices.

For further information see attached

  • Media Backgrounder on Project Silent Anzac:– ‘Project Silent Anzac talking points 3Jul14.pdf’

Attachment: 2014-0005 - AE2 - Silent ANZAC (2).pdf