Last month one of our teams replaced the bow thruster of a 191-meter roro ship during the vessel’s stop in Rotterdam. Using one of our workboats, the diver/technicians carried out the operation on-site.

The team mobilized to the ship’s location on the workboat loaded with all the needed equipment. Our workboats are fully equipped as dive support stations with hydraulic cranes, winches, nautical and communication equipment and a dive control room. They are stationed in Antwerp and Rotterdam and can be used for a wide range of operations in Belgium, the Netherlands, the United Kingdom and France. This enables rapid deployment. It also increases flexibility, which was essential during an operation like this.

After the team set up a monitoring station, the divers started the operation with a detailed inspection of the bow thruster and tunnel. In the meantime, initial preparations were made in the bow thruster engine room for the removal of the unit so that there would be no ingress of water once it was taken out.

The divers first action was to take off the external thruster tunnel grids to provide access for removal of the old unit. Next pad eyes were welded inside the tunnel to hoist the thruster unit up and down.

The next step was to secure the gearbox with hoisting equipment. The team then disconnected the unit from the engine room, removed it from the thruster tunnel and brought it to the surface.

We carried out the operation in close communication with the OEM involved. They provided a new thruster unit and prepared it for installation on-site.

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. Our diver/technicians lowered it into the water and brought it into the thruster tunnel. The team secured the unit and connected it to the engine room.

The operation ended with the removal of the pad eyes and the reinstallation of the thruster tunnel grids.

Conclusion

We assist shipowners with almost any problem they encounter with their vessel’s thruster. A wide range of underwater repair or maintenance work can be carried out on all types of thrusters. An entire unit can be overhauled, propeller blades or seals can be replaced or repair work on a specific part of a thruster performed by our diver/technicians while the ship remains afloat.

By performing the operation in Rotterdam on-site and underwater our divers made it possible for the owner to keep the vessel out of drydock. Our team worked in shifts around the clock. They finished the job within the available time frame. This allowed the ship to sail on schedule, which was a key benefit for the owner.