Number 162. Underwater bow thruster replacement in harsh conditions Fast underwater hull repairs save time and money for ship owners..

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1 Number 162 Underwater bow thruster replacement in harsh conditions Fast underwater hull repairs save time and money for ship owners

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 Hydrex offers a complete range of services to its customers, whether they need seemingly standard maintenance work, a small patch up or an extensive and out of the ordinary repair. In the first article we write about a thruster that was removed and replaced with a new one in Singapore while the 300 metre container vessel stayed at anchorage. All four blades of the thruster had gone missing and Hydrex was contacted to perform the replacement. The diver-technician team worked around the clock in shifts and the operation was concluded before the vessel had to leave the port. The second article deals with several insert and doubler plate repairs that were carried out by Hydrex teams over the last few weeks. Services like these play a very important role in helping ship owners to keep their vessels out of drydock and on schedule. Diver during installation of new bow thruster ISO 9001 certified Underwater bow thruster replacement in harsh conditions 4-7 Best regards Boud van Rompay To receive a free copy, fax to: Hydrex N.V or to hydrex@hydrex.be Fast underwater hull repairs save time and money for ship owners 9-11 KEEPING SHIPS IN BUSINESS 3

4 Underwater bow thruster replacement in harsh conditions Old bow thruster with all blades gone When a 300 metre container vessel lost the blades of its bow thruster, Hydrex was asked to remove the damaged thruster and replace it with a spare one. The operation was carried out while the vessel was at anchor in Singapore. The vessel had been sailing without a working bow thruster for quite some time which meant having to use tugboats in every port. The owners used the opportunity to have the broken thruster replaced while the vessel was visiting Singapore. 4 Hydrex team preparing the engine room for bow thruster removal

5 Due to bad weather and a current of up to three knots it was decided that, rather than using the flexible mobdocks, the entire operation would be performed underwater and in the wet. A dive control station was set up on a work barge next to the vessel. After all preliminary arrangements had been completed, the operation started on two different fronts and was coordinated by the team leader from inside the control station. Work barge with dive control station, Hydrex diver and bow thruster on the far right Because of the tight schedule of the ship, the entire operation was planned and launched as rapidly as possible. Just days after the order was confirmed, the equipment and eight Hydrex diver-technicians arrived in Singapore where the team was completed with an additional work force supplied by our local support base. One team went onboard to prepare the engine room for the thruster removal and to make sure that there would be no water ingress once the unit was taken out. Simultaneously a second team took the plunge, entered the thruster tunnel and carried out a detailed inspection of the broken unit. This revealed that the axis connecting the propeller to the gearbox had broken off, causing the blades to go missing. Preparing the new bow thruster for installation 5

6 After the inspection the thruster was secured and the brackets connecting it to the tunnel were cut. As soon as the thruster tunnel had been sealed off, the OK was given to the underwater team. The unit was then carefully lowered, removed from the tunnel and brought onto the work barge. From there it was transported to the workshop where it will be thoroughly examined to determine what went wrong. In the meantime the spare thruster had been filled with oil and sealed off and was subsequently lowered into the water and brought inside the thruster New bow thruster ready to be installed Bow thruster lowered into the water tunnel where it was secured. Once this was done, the team onboard the vessel got the thumbs up from the team leader. They then started the reinstallation of the unit while the second team simultaneously started the fitting of the propeller blades. When both teams had completed their parts of the operation, a successful test was carried out which concluded the repair. Diver during installation of new bow thruster The superintendent of the vessel, Mr. Gaby Steentjes, was impressed by the way Hydrex handled the operation and said though the installation went a little differently than decided, the team did a very good job. 6

7 Diver during installation of new bow thruster This is one characteristic of the service Hydrex aims to offer its customers. All team members are trained to be prepared for changing circumstances, allowing great flexibility without any loss of quality or safety. During this operation the diver-technician teams worked in shifts to make sure that the repair would be finished before the vessel had to depart and this despite the unavoidable loss of time that the poor weather conditions Welding work on the bow thruster brackets inside the thruster tunnel brought about. The vessel can once again use its thruster to maneuver inside ports without depending on external assistance. Propeller blades installed and secured on thruster unit 7

8 HYDREX WEST AFRICA OPENED IN PORT GENTIL, GABON Hydrex West Africa is situated in Port Gentil, Gabon right next to Cape Lopez Bay. Working closely together with the headquarters in Antwerp the office can benefit from Hydrex long tradition in the ship repair and offshore industry. Port Gentil is a general and bulk cargo port. It is the only port on the Gabon coast with a bunkering service. Thanks to the sheltered environment, the bay is ideally suited for in water work. This combined with its central location on the African West sea coast makes it the ideal place to have repair or maintenance work carried out on a ship, barge or rig in optimal circumstances. Hydrex West Africa can mobilize teams immediately to service vessels and offshore units in Port Gentil or any other suitable location in West Africa. A good example of this is the recent removal, repair and reinstallation of a 40 ton swing-up azimuth thruster of an offshore crane barge that was servicing rigs in an oil field off the coast of Gabon. The entire operation was performed while the unit stayed at anchorage just outside the oil field. KEEPING SHIPS IN BUSINESS Hydrex West Africa Sis TLC/ Cité Shell BP 2160 Port Gentil Gabon Phone : (24/7) westafrica@hydrex.be 8

9 Fast underwater hull repairs save time and money for ship owners Insert ready for full penetration weld Hydrex certified welder preparing bilge plating for insert repair on container vessel Over he last month Hydrex diver-technician teams have carried out several in-situ insert and doubler plate repairs across Europe. While these repairs may not entail a very large mobilization, they are nevertheless very important in keeping a vessel on schedule without unnecessary loss of time or money. The following article focuses on three of these operations, starting with a bilge plating repair on the port side of a 230 metre container vessel berthed in Rotterdam. An inspection performed by Hydrex divers shortly after arriving at the location revealed that an earlier installed temporary doubler plate measuring 700 x 700 mm was covering the damage on the outer shell plating. While it was being removed, a cofferdam was adjusted to the size of the affected area and subsequently installed. Next a frame was cut away to enable the team to remove the damaged bilge plating and to fit the new insert plate (measuring 480 mm x 690 mm). The insert was then welded with full penetration welding and approved by an ultrasonic testing operator. The permanent repair was carried out in accordance with Germanischer Lloyd s and will require no further care. 9 Frame reinstalled over new insert in bilge plating on container vessel

10 Shell plating repair in Flushing Hydrex was contacted to install a doubler plate over a corroded hole located under the sounding pipe in the bilge tank of a 200 metre general cargo vessel. After the exact location of the hole had been pinpointed on the outside of the hull, a cofferdam was installed over it. The corroded area was then cleaned from the inside of the vessel and filled with clad welding. A doubler plate measuring 300 mm x 300 mm was then installed over the area to prevent the damage from reoccurring. Thanks to this underwater repair the owner has the opportunity to plan in permanent repairs at a Hydrex certified welder performing wet weld more convenient time during the next scheduled docking instead of having to take his vessel into drydock immediately. Double bottom plate repair on bulker in Brixham Corroded hole filled with clad welding A 225 metre bulker had suffered a large crack in its double bottom plate and a repair was scheduled during the vessel s stop in Brixham, United Kingdom. The damage found required a 300 mm x 550 mm insert. The operation started with the removal of a 2200 mm area of the bilge keel and a 1700 sq mm area of the doubler plate underneath. This was done to enable Hydrex NV will be attending the Offshore Technology Conference in Houston from May 3 until May 6, We would like to welcome you at our booth: # Doubler plate installed over clad welding in bilge tank 10

11 Insert prior to installation on double bottom plate of bulker Taking the exact measurements of the crack the installation of the cofferdam on the underwater hull of the vessel. Next the operation continued on the inside of the vessel. The area around the crack was cut away and the insert was installed and welded into place. Its integrity was verified by ultrasonic testing and authorized by the class. This allowed the owner to sail his vessel again, permanently repaired. The repairs in this article were performed according to the Hydrex class approved procedures. As in all ope- New insert installed and welded in the double bottom plate of bulker rations carried out by the company, the essential professional standards were upheld to ensure the future safety of the ships involved. 11

12 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 12