Following a spate of stern tube seal failures, Antwerp-based Hydrex has reiterated its capability in carrying out repairs to stern tube seals during a ship’s routine port visit, saving the expense and loss of revenue of unscheduled drydocking.

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.

The company’s flexible Mobdock repair method allows seals to be repaired or replaced while the ship is afloat in harbour, allowing shipowners to keep vessels earning revenue by avoiding extra visits to drydock.

A recent stern tube repair was carried out to a tanker berthed in Antwerp. “Although this was very close to our headquarters, we can undertake similar work anywhere,” says Hydrex CEO Boud van Rompay. “Our well stocked fast response centre can deliver the necessary equipment anywhere in the world without delay. All of our offices are equipped with the latest facilities, lightweight equipment and tools, and our network of skilled technicians can be mobilized to be ready to start work as soon as the ship arrives at its next port of call.”

It is not always straightforward to replace 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 the case of the tanker in Antwerp, 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 flexible Mobdock was installed 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 co-operation 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.

Van Rompay said: “Taking advantage of the Hydrex 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.”

Antwerp-headquartered Hydrex is renowned for bringing drydock-like conditions to ships and offshore units. This helps owners to extend their vessel’s drydock interval and eliminates the loss of time and production brought about by drydocking.

Using it patented Mobdock concept (mobile mini drydock), Hydrex diver/ technicians can perform permanent repairs to all parts of the underwater ship propulsion system, as well as steel work or crack repairs in drydock-like conditions.

Because of the nature of repair work, it is often necessary for solutions to difficult problems to be worked out in a short time period, sometimes even after an operation has already started. Through a worldwide network of offices and service stations, Hydrex can provide start-to-finish solutions economically at any location.