Upon arrival at the location all equipment was transferred to a workboat and a monitoring station was set up to follow the underwater activities throughout the removal. The workboat was brought alongside the tanker and the Hydrex team boarded.

First, the thruster’s hydraulic piping was disconnected. Next, the engine room was closed off from the thruster tunnel with a temporary blank. With this done, the underwater phase of the removal could begin.

The grids were taken off each end of the thruster tunnel and the divers entered to remove the blades. Each blade was detached so as to prevent oil leaking from the thruster before a blind flange was bolted over the location where the blade had been attached.

The next step was to secure the gearbox with hoisting equipment. It was then fully disconnected from the thruster room, lowered into the tunnel and brought to shore. Finally, a flange was positioned over the space connecting the thruster to the vessel waterside, securely sealing off the thruster room. With this done, the temporary blank in the engine room was removed and less than 24 hours after the start of the job, the diving team left the vessel.

All equipment, including the gearbox and propeller blades, was loaded onto the truck and the team drove back to headquarters. The next day the dismantled thruster was delivered to the manufacturer for repairs.

The operation went smoothly and was completed faster than planned. By performing the removal in situ, Hydrex saved the ship a trip to drydock. It is currently sailing until the gearbox is repaired and ready to be installed again.