Belgium: On Site Vessel Repairs Keep Ships Out of Drydock

The Hydrex flexible mobdock technique was used to reposition the aft stern tube seal assembly of a 210-meter container ship in Le Havre. A Hydrex diver/technician team performed this operation to stop an oil blockage that occurred just after the vessel came out of drydock.

Every Hydrex office has a fast response center equipped with all the latest facilities, lightweight equipment and tools. These centers were designed specifically to increase speed of service. This made it possible for Hydrex to mobilize a diver/technician team to Le Havre from the headquarters in Antwerp immediately.

After the rope guard was removed the diver/technicians discovered that the oil flow through the stern tube seal assembly was blocked because part of the assembly had been positioned 180 degrees the wrong way. After the flexible mobdock was installed, the assembly was opened and all parts were closely examined and cleaned. This inspection revealed that all seals were in good condition but that the bonding was faulty. The seals were rebonded and the seal assembly refitted correctly.

The superintendent of the container ship in Le Havre was very satisfied with the service offered by Hydrex. He said, “Even after the typical late call on a Friday afternoon and even later that evening, Hydrex still managed to assemble and organize a team of divers that arrived the next day in Le Havre. The job was completed after four days, including full re-welding of the rope guard and shifting of the vessel to another berth. In between, new divers and technicians arrived, all of whom seemed very professional and skilled in their work. We had also used Hydrex on this ship before it went into drydock for a propeller polishing in Dunkerque and the response at that time was also very fast and the job professionally executed.”

Rudder and stern tube seal repair on tanker in Belgium

A Hydrex diver/technician team performed a crack repair on the pintle area of the rudder of a 181-meter tanker and carried out a detailed inspection of the stern tube seal assembly of the vessel while it was berthed in Ghent, Belgium. Following this inspection the team replaced the worn seals and installed a spacer ring, thus creating a new running area for the seals.

Prior to the operation the vessel was trimmed as much as possible. The Hydrex team then built a scaffolding around the rudder pintle and the stern tube seal assembly. Next they removed the rope guard and the damaged areas of the outer plating of the rudder. This allowed them to perform an inspection of the stern tube seal assembly and start the repairs to the rudder.

While the team prepared a first insert plate on shore, the inspection of the seal assembly revealed that the seals were worn and needed replacement. Next they installed the first insert and secured it while the second plate was prepared. Simultaneously another part of the team opened the stern tube seal assembly and it became clear that they needed to renew the running area of the seals as well. The team did this by installing a new spacer ring on the stern tube flange after which they replaced and bonded the three seals.

Hydrex performed all operations under DNV requirements which were verified by an attending surveyor. The diver/technician team rotated in shifts to finish both repairs in the shortest possible time and avoid any unnecessary delays for the vessel.

Fast response prevents time loss for general cargo vessel in the U.S.A.

When oil was leaking from the stern tube seals of a general cargo vessel, Hydrex mobilized a certified diver/technician team to the vessel’s location in Mobile, Alabama, to perform underwater stern tube seal repairs before the ship was transferred to a new chartering party.

Hydrex had already performed a similar operation on one of the customer’s other vessels so he was aware of Hydrex’s well-trained diving teams and ability to handle this kind of situation without loss of quality or time for the customer. Because the U.S. Coast Guard has very strict policies concerning environmental risks, they would not allow the vessel to sail to a different location before the oil leak had been permanently fixed.

A team immediately left from the Hydrex office in Clearwater, Florida, together with the needed equipment, and set up a diving station at the berthing location of the ship. After the Hydrex flexible mobdock was installed around the stern tube seal assembly and a dry underwater environment was created, the damaged seals could be replaced.

In order to provide the customer with the fastest possible response, flexibility was essential throughout the entire operation. Hydrex was able to perform the repairs in a very tight timeframe and made sure that the new charterer could sail the vessel free of oil leaks.

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Source: hydrex, August 4, 2011;