Underwater removal and reinstallation of bow thruster on container vessel

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1 Number 165 Underwater removal and reinstallation of bow thruster on container vessel

2 Class Accepted underwater stern tube seal repairs under warranty Using our flexible mobdock method to create a dry underwater environment, we have carried out stern tube seal repairs and replacements underwater for some years now in cooperation with top specialist suppliers. This technology brings drydock conditions to the ship rather than having to take the ship to drydock, saving a considerable amount of time and money in doing so. This class accepted method is performed by our diving teams under our warranty. It can be used while the ship is carrying out its usual cargo or other commercial operations in port. Visit the special seal repair section on our website for more information and examples of the many seal repairs we have performed in recent years. UNDERWATER TECHNOLOGY 2

3 Editorial Table of contents For a company that offers services to the shipping industry it is very important to be flexible. Circumstances can change from one moment to the next and it is essential that one reacts to this without loss of time or quality of service for the customer. Ships have to keep a very strict schedule. Every day that a vessel has to go off-hire costs the owner a great deal of money. It is with this in mind that Hydrex has specialized in perfecting systems to perform almost all repairs underwater, and with the greatest possible flexibility, to keep ships out of drydock. Overhauled bow thruster prior to reinstallation ISO 9001 certified In this magazine we give you some insight into how our certified divers carried out the removal and reinstallation of the bow thruster of a 330 metre container vessel despite very challenging circumstances. The operation was carried out in multiple stages during several of the ship s stops so that it could keep to its schedule and did not have to go off hire. Best regards Boud van Rompay To receive a free copy, fax to: Hydrex N.V or to hydrex@hydrex.be Underwater removal and reinstallation of bow thruster on container vessel 4-7 KEEPING SHIPS IN BUSINESS 3

4 Underwater removal and reinstallation of bow thruster on container vessel Hydrex lightweight equipment ready for mobilization from fast response centre Due to a malfunctioning bow thruster, a 334 metre container vessel had to use the services of a tug boat for port maneuvering, so its owners requested Hydrex to take care of the removal, transportation and reinstallation of the unit. The operation was performed in stages in several locations to allow the vessel to keep to its sailing schedule. To offer the best possible repair schedule to the customer it was decided to perform the operation in the wet. This proved to be no problem for the Hydrex certified diver-technician team that assisted the vessel. Like all Hydrex staff members, they are trained to adapt easily and quickly to the constantly changing circumstances that are part of the job for any company offering services to the shipping industry. Bow thruster unit brought to the surface 4

5 Underwater removal of bow thruster unit Together with all the necessary equipment, the team travelled to Rotterdam where the operation started with a thorough inspection of the bow thruster unit. One by one the blades were then detached and replaced by blind flanges to prevent oil from leaking from the thruster. Then the lifting and hoisting equipment that would be used to secure the unit during the second stage of the operation was installed. In the meantime, initial preparations were made in the bow thruster engine room for the removal of the unit, so that there Hydrex diver-technicians during preparation of the engine room the Hydrex Fast Response Centre by the team and sent on to Norway for repairs. Reinstallation of repaired unit Hydrex diver-technician climbing out of the water after working in the thruster tunnel As soon as the overhauled bow thruster gearbox was delivered to the Hydrex headquarters, the divertechnician team and the unit were mobilized to the container vessel s next port of call: Le Havre. After a monitoring station had been set up next to the ship the team removed the blind flange inside the thruster tunnel. The unit was then put on a cradle that was designed especially for bow would be no ingress of water once the unit had been taken out. The vessel then left for Southampton where it met up again with the team which immediately continued getting the engine room ready. Next the support brackets connecting the gearbox to the thruster tunnel were cut and the unit was secured with chains. It could then be fully disconnected from the thruster room and was carefully lowered, extracted from the tunnel and brought to the surface. The second part of the operation ended with the installation of a blind flange to seal off the thruster tunnel from the engine room. The bow thruster unit was then transported to Bow thruster unit on special cradle ready to be brought back into the thruster tunnel 5

6 Thruster unit and propeller blades at Hydrex headquarters prior to overhaul Welding work on blind flange used to seal off thruster unit after blade removal After fast stops in Dunkirk and Hamburg the team met up with the vessel in Rotterdam where the chain blocks were removed, following which the propeller blades were reinstalled one by one. To prevent water from ingressing and oil leaking, the blades were positioned at a 6 o clock position instead of the more common and easier 12 o clock position. Subsethruster operations and prevents the unit from tipping. As it can be adjusted to the size of the thruster, it allowed the Hydrex divers to bring the unit back into the thruster tunnel in one take. Due to the size and weight of the bow thruster unit, special measures were taken to lower the thruster unit and bring it inside the tunnel where it was repositioned by using chain blocks. Despite the extra difficulty this entailed, the team was able to reposition the gearbox with only a minimum of delay. The unit was then secured with bolts, but the chains were kept in place because there was no time left to reinstall the brackets before the vessel had to leave for the next port on its schedule. Hydrex monitoring station and overhauled bow thruster unit in Le Havre 6

7 Hydrex team members manoeuvring thruster unit quently, the support brackets that connected the bow thruster unit to the thruster tunnel wall were reinstalled. The ship then sailed to Southampton. At this location the brackets were secured, the pad eyes removed and the propeller blade bolts secured with wire. This concluded the repair. The vessel can now maneuver inside ports again without the need of a tugboat. Hydrex s flexibility allowed the company s technical department to adapt the different parts of the repair to the sailing schedule. The delay for the customer was reduced to the strictest minimum and by performing both the removal and reinstallation of the bow thruster unit underwater the vessel did not have to go into drydock. Bow thruster unit lowered into the water for reinstallation in thruster tunnel 7

8 Keeping ships in business Hydrex underwater technology and services provide high quality solutions to the repair and replacement problems encountered by ships and offshore vessels. We deliver a complete line of services that may reduce or avoid off-hire time entirely. From major projects to simple inspections, Hydrex has the worldwide facilities and capability to meet your demands. Drydocking is not necessary so time, trouble and expense are saved by doing work in-situ. Hydrex services cover highly technical major repairs or replacements of a ship s external underwater equipment such as thrusters, propellers, rudders, stern tube seals and damaged or corroded hulls. Hydrex Headquarters Antwerp Phone: (24/7) hydrex@hydrex.be Fax: Hydrex US - Tampa Phone: (24/7) info@hydrex.us Fax: Hydrex Spain Algeciras Phone: (24/7) info@hydrex.es Fax: Hydrex India - Mumbai Phone: (24/7) mumbai@hydrex.be Fax: Hydrex India - Vishakhapatnam Phone: (24/7) vishakhapatnam@hydrex.be Fax: Hydrex West Africa Port Gentil Phone: (24/7) westafrica@hydrex.be 8