Underwater bow thruster repairs

06.09.2021

Maritieme toeleveranciers, Scheepsbouw

An entire unit can be overhauled, propeller blades and seals can be replaced or repair work on another specific part of a thruster can be performed on-site or inside the tunnel. These repairs are performed in cooperation with OEMs.  They can be carried out while the vessel stays afloat with minimum impact on its schedule.

Tunnel thruster operations specifically are carried out using the company’s flexible mobdocks that close off the thruster tunnel on both sides. This allows divers to work in a dry environment around the unit. The lightweight mobdocks can quickly be transported to any location around the world. All operations can be carried out in port during cargo operations or at anchorage.

The size of the thruster does not matter. The flexible mobdocks can be easily adapted to the circumstances. They can be used for a wide range of repair or maintenance work on all types and sizes of thrusters and vessels.

Replacement in stages keeps cruise ship on schedule

A 208-meter cruise vessel sailing in the Caribbean suffered steering problems after one of its two bow thrusters malfunctioned. Having to depend on assistance every time the ship berthed would quickly become very expensive. Going off-schedule, however, to have the bow thruster replaced would cost the owner both in finance and reputation.

A solution was therefore needed that could be carried out on-site without interrupting the vessel’s schedule. Enter the Hydrex tried and tested flexible mobdock technique and their experienced diver/technicians.

There was only a time frame of eight hours at each port of call during the ship’s cruise in the Caribbean. It was therefore important that the operation was split up in parts that could be finished before the vessel had to leave again. A perfect planning and constant communication between the technical department in the office and the team on location was essential in achieving this.

Underwater reinstallation avoids delay for container vessel

A month after Hydrex removed the bow thruster of a 300-meter container ship a team once again mobilized to Italy to reinstall the overhauled unit underwater.

The available time window for the removal of the bow thruster had been very short because of the tight schedule of the vessel. For this reason the job was split in parts, performed in different ports. The time frame for the reinstallation was slightly larger, allowing the team to carry out the job during a single stop of the vessel. The divers used flexible mobdocks to close off the thruster tunnel once the overhauled bow thruster had been brought into the tunnel. All water was removed from the tunnel.

This created drydock-like conditions while the vessel stayed afloat. The team then secured the unit and connected it. Once this was done the thruster propeller blades were installed one by one. With these in position the ship was ready to sail.

Hydrex divers worked in shifts around the clock to finish all tasks as fast as possible. As a result the charterer did not have to worry about his vessel’s schedule.

Fast response keeps vessel on project in Australia

Hydrex removed the bow thruster of a large offshore supply vessel and reinstalled the unit after it was overhauled.  By carrying out both parts of the operation underwater while the vessel was at anchorage in Dampier, Australia, the ship did not have to go to drydock and could stay on the project.

Despite the remote location of the vessel, the company’s technical department was able to make all logistic arrangements and organize a mobilization of the equipment swiftly. Over the years Hydrex has carried out many operations in Australia, most of which were done with a limited window of opportunity available.

After the divers removed the bow thruster unit it was brought to a local workshop where it was overhauled by a technician team of the OEM. The Hydrex team remained on stand-by so that they could immediately start the dry reinstallation when the bow thruster arrived back on location.

During the entire operation there was a close cooperation with the OEM so that the different parts of the repair were perfectly coordinated. This allowed Hydrex to offer the best possible solution to their customer within the shortest possible time-frame.

Highlights

Banner