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Ex-HMAS Adelaide dive site

Ensuring diver safety: Ex-HMAS Adelaide Dive Site closure

The ex-HMAS Adelaide, an Oliver Perry-class frigate and former Royal Australian Navy warship was scuttled in 2011 to create an artificial reef for marine life and the enjoyment of divers.

Located about 1.8 km off Avoca Beach, near Terrigal on the Central Coast of New South Wales, the ship lies approximately 32 meters deep and has become an attraction for divers.

However, structural damage sustained during a recent storm means the dive site has been closed and mooring buoys removed while a comprehensive safety assessment takes place.

Artificial reefs like the ex-HMAS Adelaide are regulated under Commonwealth law to ensure they do not pose a significant threat to the marine environment and users.

Storm damage: The ex-HMAS Adelaide suffered significant damage during recent storms and heavy seas. Investigations are now underway to understand the safety risks the damage poses to divers and guide decisions on the future of the site.

Structural integrity: The vessel's aluminium superstructure has been weakened by galvanic corrosion and separated from the steel hull during heavy seas. The superstructure now lies on the seabed, partly resting against the main deck.

Diver safety: The current condition of the wreck poses considerable risks to divers. The structure is now located at an increased diving depth and sharp aluminium fragments and unstable structures, pose entrapment risks. The site no longer meets the safety standards outlined in the Long-Term Monitoring and Management Plan for recreational diving.

Navigation markers: The 2 yellow special navigational markers moved during the storm and are no longer in their original positions. For the safety of our community and divers, the red mooring buoys have been removed, and the public should not attempt to dive at the site.  

Marine life impact: The storm has cleared most fixed marine life from the wreck, including the rare Cauliflower Coral Sponges that previously covered the forward deck. We are working with relevant agencies to maintain the site's environmental integrity and minimise the impact on marine life.

Next steps:  

  • Further monitoring and investigation of the ex-HMAS Adelaide site is underway to assess the safety and stability of the dive site.  
  • Updates on the future of the dive site will be provided when monitoring and investigation activity has concluded.

Keeping up to date with our work

We will update this page as the project progresses.

To speak to an officer  

Contact us and quote Closure of Ex-HMAS Adelaide Dive Site

Location image

 

Drawing of the displaced superstructure HMAS Adelaide on the seabed
Right: A drawing of how the wreck is now. The displaced superstructure is shown in magenta and lays off to the port side. Note: the mast is still upright but resting on the seabed.

About artificial reefs

The ex-HMAS Adelaide was prepared and sunk to create an artificial dive reef.

An artificial reef is a structure placed on the sea floor to attract new marine life to an area. These structures may improve fishing opportunities, serve as dive sites, help protect the coast , deter trawling activity, and reverse habitat loss.

The reef develops over time. It goes through various stages of marine growth and occupation, eventually becoming home to a thriving marine ecosystem that attracts divers from all over the world.

When a 'new' structure is introduced to the marine environment, tiny organisms such as microscopic algae in ocean waters land on its surface, creating a first layer of ‘slime’. Layer upon layer of micro-organisms slowly settle on these surfaces, creating a food source for many more permanent and visiting organisms. Eventually, a more prominent reef develops on the surface of the structure, which attracts fish and other marine life. 

Environmental monitoring and reporting

Australian law regulates the creation of artificial reefs under the Environment Protection (Sea Dumping) Act 1981 (Commonwealth).
A sea dumping permit ensures that creating an artificial reef does not threaten the marine environment or marine users. After a comprehensive environmental assessment, a permit was issued for scuttling (sinking) the ex-HMAS Adelaide.

The Administrative Appeals Tribunal considered a wide range of environmental issues when it reviewed the permit and allowed the scuttling to go ahead.

An ongoing condition of the permit is that the department must monitor and report on the artificial reef, in keeping with a long-term monitoring and management plan . All results of this monitoring are available below.

In 2016, the ecological monitoring done in the 5 years since the scuttling was reviewed.

Post-scuttling report April 2011

This report confirms the date and time of placement, position, water depth, inspection dives and position of navigation markers.

Additional surveys and reports

Reef community and sediment movement

These reports describe the development of the reef community.

Sediment sampling

These reports monitor seabed sediment quality and movement, including how metal corrosion and paint degradation could potentially influence the surrounding environment.

Bioaccumulation studies

Bioaccumulation monitoring determines if resident marine species are likely to be affected by the vessel’s zinc chromate paint.

Structural reports

Regular structural inspections and assessments of the ship are conducted in line with the long-term monitoring and management plan. The ex-HMAS Adelaide has settled on the ocean floor in an upright position. Download a diagram showing the depth measurement and ship schematics.

Divers’ inspection reports

Qualified commercial divers regularly inspect the ex-HMAS Adelaide and report on the condition of the wreck.

Engineers’ reports

Marine engineers review the divers’ reports, assess the condition of the wreck and identify any factors that may require ongoing monitoring.