Stern Tube Leaks on Cargo Vessels Need Urgent Attention

BELGIUM – WORLDWIDE – Much has been made of the necessity to ensure waste water emanating from modern cargo ships has been treated as demanded by MARPOL regulations, but the International maritime Organization (IMO) rules refer to any pollution, and one common, but insidious cause, is leaks from a vessel's stern tubes, allowing and ingress of water and, all too often, the passage of oil into the surrounding waters.

Stern tube seals can suffer undue wear or damage due to a variety of causes, causing water ingress and oil leaks. With ever-tightening environmental regulations resulting in heavy penalties for oil pollution, rapid and timely repairs are essential. After a recent spate of such failures Antwerp headquartered firm Hydrex has reiterated its capabilities in carrying out repairs to stern tube seals during a ship’s routine port visit, saving the expense and loss of revenue of unscheduled dry docking.

The problem is not always straightforward when replacing seals. There can be considerable variation in the size of the stern tube itself and the liners can be worn down and show ruts. In one case of a tanker in Hydrex’s home port, a thorough underwater inspection of the stern tube seal assembly revealed that a rope and a fishing net had become entangled. Hydrex divers removed both, and the company’s flexible Mobdock repair, which enables seals to be repaired or replaced while the ship is afloat in harbour, was employed to allow the repair work to be undertaken in dry conditions.

Hydrex technicians removed three damaged seals and replaced them with new ones. Hydrex worked in close cooperation with the seal manufacturer, which allowed the company to provide the client with original spare parts, thus guaranteeing a sound repair using the best quality material. To help ensure this, a technician from the seal manufacturer was in attendance during the repair. Hydrex CEO Boud van Rompay, commented:

“Taking advantage of the flexible Mobdock technique the team was able to carry out the entire repair on-site and underwater. Because all the required equipment is ready to be transported at any time, there is no wasted time making preparations and it is possible to carry out the entire job without delays to the vessel’s schedule.”