Downer NZ

CATEGORY 1B: Projects with a value of less than $5 million (Company turnover greater than $10 million)

PROJECT: Mystery Island Tender Jetty, Vanuatu. CONTRACTOR: Downer NZ

Tropical isolation challenges

Mystery Island is a remote, uninhabited Pacific island situated at the southern-most tip of the Vanuatu archipelago, approximately 300 kilometres southeast of the main island and capital at Port Vila.

Royal Caribbean Cruises, through its agents South Seas Shipping (Vanuatu), and in conjunction with the local government, required a new landing jetty so that passengers could be safely tendered and disembarked on the island to enjoy its tropical isolation, pristine beaches, swimming and snorkelling activities.

Downer NZ was contracted to provide the site investigation, project design, off-site fabrication work and the physical construction.

The prefabricated aluminium superstructure for the jetty which was constructed to within an 80mm tolerance, was mounted on 36 steel piles driven into the coronous substrate of the seabed, with the precast head stocks then fitted into the pile heads. To ensure the piles were driven to within the 80mm tolerances of the superstructure and to allow for the wave motion of the barge-mounted crane a survey setup on the beach recorded each pile position and relayed this information to the piling supervisor on the barge. The landing platforms and stairs were fitted into the concrete headstocks and the fibreglass reinforced plastic (FRP) non-slip decking, with mooring bollards and fenders affixed and aligned along the jetty facia.

The remote site brought a number of challenges in logistics: for example, equipment including the 80-ton crane and prefabricated sections of the jetty had to be shipped from Auckland in parts, reassembled at Port Vila and barged to the site.

Weather was also a factor with unpredictable wind and tides. There was also a requirement to keep the old existing jetty operational while construction was taking place, and to observe protocols associated with working in the marineprotected area.

As Downer staff were living on-site and working in high humidity and heat, a midday ‘down-time’ for all personnel, including the local workers, was adhered to throughout the project with strict health and safety policies followed.

There were no injuries or incidents and the project was delivered on time, to budget and to an exceptionally high professional standard. l