Back in November a fully loaded bulk carrier contacted Subsea Global Solutions (SGS) with a shaft seal issue. Initial reports from the vessel were that they were losing all stern tube oil into the vessel, they were experiencing heavy water ingress through the FWD seal system into the engine room, and the internal seal system clamp ring shifted approximately 70 mm in-board. By this report, it was immediately known this was not a typical shaft seal repair.
The vessel was towed from an anchorage in Russia across the Black Sea to a more favourable location in Eastern Europe. Teams from SGS offices in Vancouver, Miami, Long Beach, Halifax, Houston, and Tampa were sent to attend.
Once inspections began, it was found that the tail shaft had dropped outside acceptable tolerances due to bearing failure. This bearing failure was the root cause of the initial reports.
A plan was put together for an emergency repair for the vessel so it could continue on its way to deliver cargo and then go to drydock. Working alongside the responsible Class Society, it was decided that if the shaft seal integrity could be reinstated and a running test could be conducted with Class in attendance to their satisfaction, the vessel would be allowed to sail.
For the seals to be brought back into eccentricity with the shaft, modifications to the seal housing flange were conducted. This consisted of disassembly of the entire split type seal system inside the SGS Transhab habitat and the housing flange modified in accordance with specifications developed by SGS’s engineering department with consultation with the seal supplier. Once machined, the system was assembled with new bonded shaft seals. The aft seal assembly was aligned with the shaft eccentricity within original tolerances.
The internal seal assembly and clamp ring was put back into radial and axial alignment and backed up by an additional hold back fabricated onsite as extra precaution.
After working around the clock in extreme weather, the running test was conducted pier side. All testing was completed and Class approved for the vessel to make a one-way trip to its next port of call for cargo discharge. The vessel arrived without fail, discharged its cargo and entered the drydock for permanent repair.
Throughout this transit the vessel maintained close contact SGS by providing continuous updates to SGS technicians.
Source: SRN (Ship Repair Newsletter) 1697