Extensive work is needed to repair essential tugboat berths in Dockyard, according to a recent planning application.

The application proposed demolishing existing tug docks and ancillary structures located on the North Arm, and construction of a new dock at the location.

The work was also said to have potential for uncovering relics from Dockyard’s past.

Andrew Dias, the general manager of Wedco, said last summer that the roughly 200-year-old stone barrier had “several areas of erosion that will need to be attended to, and this will likely be completed in a phased approach”.

The project was put out to tender this year, and the application is scheduled to be discussed by the Development Applications Board this week.

Planning documents said that the tugboats at the North Arm of Kings Wharf are required to service visiting cruise ships.

“Their continued and safe operation is of national economic significance,” the documents state.

“The current berths for the tugboats located at North Arm have signs of significant structural deterioration born out of the high-powered propulsion units the boats use.

“Replacement of the boats and units is not considered cost-effective given their age and condition and this would not alleviate the structural condition of the dock.”

The documents said a structural condition survey carried out last year by Brunel Ltd revealed areas of “significant undermining and cave formation” beneath the dock and found the structure was “beyond repair”.

“The report recommended that in the areas of the tugboat berths immediate action is required to prevent failure of the piers and to remove the threat to the safety of the tugboat operators and of damage to the tugboats,” the documents continued.

“There is a risk to both operators and vessels should the erosion be left unattended.

“The planning application has therefore been submitted including proposals which provide protection for the existing natural environment and a safe working environment for the tugboats to operate in.

“The extent of proposed works is limited to approximately 365ft, which is in line with the requirement to dock three tugboats.”

The documents said that the North Arm location was the only one that could provide hurricane berths to tugboats, and that alternatives such as Heritage Wharf and Cross Island were unsuitable.

The Historic Wrecks Authority recommended that an archaeologist be on-site for the project, noting the likelihood that cultural artefacts from convict hulks, floating prisons used in the construction of Dockyard, could be found.

“These were present in concentrated cultural layers as features known as middens,” the HWA said.

“These middens are made up of the trash and personal effects of those living in the hulks, deposited as layers on the bottom adjacent to the sides of the hulks, resulting in an underwater cultural layer or debris field on the inside and outside of the hulks, with the outside being deeper in water and the inside on the slope itself.”

The HWA said there was a “strong possibility” that convict hulk middens could be beneath the surface of the North Arm, and the project was an opportunity to potentially discover “undisturbed cultural layers related to the active use of the convict hulks”.