Lihou Reef AToN Upgrades

Lihou Reef AToN Fender System Replacement

PMG recently completed a fender system upgrade on an AMSA Aid to Navigation (AToN) located approximately 330 nautical miles east of Townsville in the Coral Sea.

The structure consists of a four-piled platform, with a fifth pile supporting a clamp-on fender assembly that allows service vessels to safely push up against the structure and access the AToN.

The existing fender system had deteriorated, and under our contract with AMSA, PMG was engaged to design, construct, and install a full replacement system on the existing pile. The new fender had to fit over a Denso 2000FD jacket system (installed as part of the works) and incorporate shear keys to prevent rotation of the clamp-on structure.

Working closely with AMSA and our design partners, Royal Haskoning, we developed a robust, site-friendly, and durable clamp-on fender system. The unit was fabricated entirely from 316 stainless steel with D-fender rubber and built in-house by PMG fabricators at our Townsville workshop.

Once completed, the system was loaded onto our 45 m × 15 m barge PMG151, along with an 80-tonne crawler crane and all necessary project equipment. The barge was then towed 330 NM to site by our support tug PMG Pride.

On arrival in deep water outside the reef lagoon, the barge was safely anchored, and the tow line was released. A safe route into the AToN was surveyed by small craft, as the shallow approach prevented the tug from bringing the barge all the way in. Two support vessels were used to manoeuvre the barge over the shallows and position it alongside the AToN, where it was securely moored for the duration of the works.

Site works included removal of the old fender system, cleaning and refurbishment of the existing mounting pile, welding of shear keys, installation of the Denso Seashield 2000FD jacket system (both above and below water by divers), fitting of the new clamp-on fender assembly, and final installation of anodes underwater.

The project was completed smoothly and without incident, and the crew returned safely from what was truly an incredible and rarely visited location.