Two months after Hydrex divers removed the bow thruster of a 150-meter roro ship, they once again mobilized to a vessel in Algeciras, Spain to reinstall the unit. By performing both operations underwater, the thruster could be overhauled without making costly changes to the schedule to take the ship to drydock.
The reinstallation was carried out by reversing the procedure used for the thruster’s removal. The team once again set up a monitoring station next to the vessel. The divers then started the operation with a detailed inspection of the bow thruster tunnel. In the meantime, initial preparations were made in the bow thruster room for the reinstallation of the unit so that there would be no ingress of water once it was taken out.
Because the thruster was fully assembled and prepared, it could be installed in its entirety without the need to create a dry environment in the tunnel as is required when the blades are installed separately. The diver/technicians lowered it into the water and brought it into the thruster tunnel. The team secured the unit and connected it to the bow thruster room.
The operation ended with the removal of the pad eyes and the reinstallation of the thruster tunnel grids.
The team worked in shifts around the clock and finished the job within the available time frame. This allowed the ship to sail on schedule, which was a key benefit for the owner.
Performing a job like this takes a lot of planning. This can only be done successfully by staff who have familiarity with such operations and have the relevant know-how and equipment.
Both the removal and reinstallation of the thruster in Algeciras were done underwater, but this is not always the case. Hydrex teams can also remove the unit before the ship enters drydock so that it can be brought to the manufacturer for overhaul ahead of time. When the vessel enters drydock the overhauled unit is ready for reinstallation without any delay. The reverse procedure is also possible. If the thruster is removed in drydock, it can be reinstalled underwater in dry conditions at a later date after it has been overhauled. In this way the ship can leave drydock while the unit is still with the manufacturer.
