Hydrex mobdock method used for on-site stern tube seal replacement
The mobdock allows personnel to work below the waterline, in dry conditions (Source: Hydrex)
Hydrex has conducted stern tube seal replacements on one 294m tanker in Cartagena, and one 195m RoRo ship in Burnie, Tasmania, using the ‘mobdock’ method introduced in 2002.
The Mobdock consists of a sealed, half-torus shaped underwater structure which is wrapped around the vessel’s propeller shaft. This allows divers to work in the dry, permitting direct physical access to stern tubes beneath the waterline.
In each case, after an initial cleaning of the work environment, the divers installed the Mobdock, and disconnected the split ring so it could be brought to the surface and cleaned. Then the divers proceeded to replace the seals with new ones, and conducted leakage tests to ensure the new seals were properly secured.
Hydrex claims that its flexible mobdock method allows stern tube repairs to be undertaken at sea rather than at the yard, even performing the seal replacements during a cargo-loading operation, meaning that vessels would not have to wait for slot alongside at a shipyard. “Because all the required material is ready to be transported at all times, no time was lost making preparations,” said Hydrex.
