240T Liebherr Offshore Crane, refurbishment of Zollern Hoist Winch
The vessel was operating offshore Vietnam, when the 30 ton aux. winch developed a problem. A Liebherr Specialist Engineer from ALATAS Singapore was flown in to assess the problem. As it turned out, the needle bearings between rope drum and supporting housing hat disintegrated, causing major damage on the running surfaces of the rope drum and the end housing.
The winch is a special, one-off Zollern winch, type ZHP 4.31, with a length of 4.4.meter and a weight of 6 ton. Arrangements where made to remove the rope winch in Vung Tau and ship it to ALATAS Singapore, which is a Zollern approved winch and gearbox repair station. Tailored repair drawings where made up and the rope drum was repaired via machining down the wasted needle bearing raceways and shrink-fitting a matching repair ring.
The repaired rope winch then was shipped back to the vessel and installed by ALATAS Engineers. Limit switch adjustments, function testing and a proof load test was carried out to verify the successful winch repair.
Badly damaged drum housing
Badly damaged end housing
Damaged end housing raceway
Lifting drum
Removing planetary gearbox in Vietnam Workshop
Removing rope winch
Removing rope winch
Removing rope winch
Removing rope winch
Removing rope winch
Removing rope winch
Assembly of planetary gearbox into Rope Drum
Assembly of planetary gearbox into Rope Drum
Assembly of planetary gearbox into Rope Drum
Assembly of planetary gearbox into Rope Drum
New Needle Bearings
Newly fabricated end-housing
Newly fabricated end-housing
Overhauled Gearbox, assembled
Repair ring with new needle bearing raceways, shrink-fit into rope drum