Underwater Bow Thruster Reinstallation

Three months after Hydrex diver/technicians removed the bow thruster of a 294-meter container vessel in Tacoma, a Hydrex team once again mobilized to this location to reinstall the overhauled unit underwater with the use of the Hydrex flexible mobdock.

The superintendent of the ship was very satisfied with the first part of the operation. The job was completed well within the available time frame thanks to good team work of the Hydrex divers, the ship staff and the floating crane operator. For this reason the customer asked Hydrex to take care of the reinstallation as well, which was carried out last month.

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 team positioned the bow thruster 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, making it much easier to handle. The Hydrex divers could lower the unit into the water and maneuver it inside the thruster tunnel in one take. The team positioned the bow thruster and secured the unit.

The team then used the lightweight flexible mobdocks developed by Hydrex to close off the thruster tunnel on both sides. This allowed the diver/technicians to evacuate all the water from the tunnel and create a dry working environment around the bow thruster. The thruster propeller blades were then reinstalled one by one. The team completed the operation by reconnecting the thruster unit to the engine room.

Hydrex can assist shipowners with almost any problem they encounter with their vessel’s thruster. A wide range of repair or maintenance work can be carried out to 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 can be performed by Hydrex diver/technicians on site. All of these repairs can be carried out without the need to drydock the vessel.

Off-hire time causes a substantial loss of money. The teams therefore worked in shifts during both the removal en reinstallation of the bow thruster. This was done to perform the bow thruster operations within the shortest possible time frame, saving the owner the time and money which going to drydock would have entailed.