Tasmanian Cargo Ship – Overboard Pipe Manufacture and Installation

The ship is the primary transporter of cargo between Melbourne and Burnie (Tasmania). It was the largest cargo ship registered in Australia when it was launched in 2019. The vessel is 211m in length (28m beam), with a capacity of 700 TEU and 3000 lane-metres. It is operated by a major Multinational Freight Forwarder.

The job involved replacing an existing a 500mm Nb overboard discharge pipe. The vessels managers had previously determined, via ultrasonic thickness inspections, that the pipe required replacement. The defective pipe penetrated the vessel’s hull below the water line, meaning that the pipe could not simply be cropped and replaced, as this would result in an ingress of water and catastrophic failure. Adding to the complexity of it all, all work had to be performed without disrupting the vessels operational demands.

Our job involved attending Melbourne, viewing the ship and formulating an acceptable repair methodology with Lloyds and the vessel managers. We then attended Burnie to commence works. The first critical step was to weld a cofferdam onto the external surface of the hull (over the pipe penetration). This was conducted by SDS divers from Subsea global Solutions and allowed our fabricators to crop the existing pipe without the ingress of water.

Our fabricators then went about jigging the removed pipe and fabricating the replacement pipe. The jig ensured the manufactured pipe would be an exact replica of that removed. Once fabricated, all welds were checked via NDT and the pipe was coated in appropriate wear resistant coating. The pipe was then offered up to the installation point for fit-up checks prior to welding. Final welding and NDT checks were then conducted prior to removing the installed cofferdam.

The project was conducted safely and without delay to the vessel. Another happy customer!