Marine Link
Wednesday, October 26, 2016

Rapid Underwater Bow Thruster Removal Avoids Drydocking

May 28, 2013

Photo: Hydrex

Photo: Hydrex

A Hydrex diver/technician team mobilized to Tacoma, Washington, U.S. last month to remove the bow thruster of a 294-meter container vessel. The unit needed to be overhauled. Hydrex performed the operation underwater in a very short time frame. This made it possible for the owner to keep his vessel out of drydock.

Together with all the necessary equipment, the team mobilized from the Hydrex office in Clearwater, Florida to the vessel’s location. After they set up a monitoring station on a workboat, the divers started the operation with a detailed inspection of the bow thruster unit and tunnel.

One by one, the diver/technicians then detached the blades and replaced them with blind flanges to prevent oil from leaking from the thruster. 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 the unit was taken out.

The next step was to secure the gearbox with hoisting equipment. The team then disconnected the bow thruster unit from the engine room and lowered it onto a cradle. This cradle was designed especially for thruster operations. It can be adjusted to the size of the unit. In this manner the thruster is prevented from tipping over and Hydrex divers can remove the unit in one take.

Simultaneously the team installed a blind flange to seal off the thruster tunnel from the engine room. Once the unit was lifted onto the workboat, the team prepared it for transport to the manufacturer.

Performing a job like this on a tight schedule 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. Hydrex has a technical department capable of executing all the required planning. Our diver/technicians are trained and qualified to perform the full range of required class-approved repair procedures in even the harshest conditions.

Off-hire time causes a substantial loss of money. The teams therefore worked in shifts to perform the bow thruster removal within the shortest possible time frame. This saved the owner the time and money which going to drydock would have entailed.

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