Introduction
A tug operating in demanding conditions required essential maintenance to ensure continued reliability. Initially, Bartech Propulsion was called in to remove and reinstall the port-side Kongsberg US255 thruster to facilitate non-destructive testing (NDT) of the propeller shaft. However, during inspection, significant oil leaks and water ingress were identified, necessitating a more extensive overhaul.
Through a proactive and thorough approach, our team worked closely with the operators to replace both port and starboard propeller shaft seals, preventing potential failures and ensuring the vessel remained fully operational.
Plan
The initial scope involved removing the port-side propeller for inspection, but upon arrival at the shipyard, we conducted a full assessment of the propulsion system. During this inspection, we discovered:
- A slight impact-related blade tip deformation.
- Oil leaks and signs of water ingress at the propeller shaft seals.
- Deep grooving on the liner, leading to continued leakage.
Recognising the potential for similar wear on the starboard side, we advised a further inspection. Sure enough, when we removed the plugs between the seals, we found no lubrication oil and a significant amount of emulsified water-contaminated oil, strong indicators of liner damage.
To prevent long-term propulsion issues, we recommended replacing both sets of propeller shaft seals. The decision was made to proceed with this approach, and new seal housings and liners were ordered while preparations were made for the expanded work scope.
Execution
We began by carefully removing both the port and starboard propellers using hydraulic expansion techniques. Each component was meticulously marked for precise reinstallation, ensuring perfect alignment with OEM specifications.
With the propellers removed, we assessed the liner damage and confirmed that deep grooves across all three running tracks were the root cause of the leaks.
To minimise downtime, one of the Bartech team hand-carried critical parts from Holland while a detailed lower gearbox inspection was conducted on both propulsion units. Gear tooth contact and backlash were within acceptable limits, confirming that no further intervention was required.
To prepare for reassembly, we:
- Drained and cleaned the header tanks.
- Flushed pipelines with diesel.
- Ensured all mating surfaces were free from contaminants.
Once the replacement components arrived, we:
- Installed new seal boxes and liners, torquing all fasteners to OEM specifications.
- Secured the liners using precision heating techniques to achieve a flawless fit.
- Reinstalled the propellers, aligning with the original datum points and hydraulically expanding them onto the taper for a secure drive-up.
- Filled, vented, and secured the seal boxes with locking wire before refilling the oil system.
This thorough and methodical approach restored the propulsion system to optimal performance, ensuring long-term reliability for demanding operations.
Results
Although the job exceeded the original schedule, our intervention helped identify and address critical issues that, if left unchecked, would have likely resulted in costly downtime and major repairs.
- Full propulsion system reliability restored – Both port and starboard shafts were sealed correctly, eliminating oil leaks and water ingress, preventing future failures.
- Proactive issue resolution – Our thorough inspection uncovered liner damage that may have otherwise gone unnoticed, safeguarding against future operational disruptions.
- No additional gearbox repairs required – Internal gear sets were inspected and confirmed to be in good condition, avoiding unnecessary repair costs.
- Operational readiness ensured – Final pre-departure checks showed no further leaks, confirming that the vessel was ready to return to service with restored reliability.
While we were advised not to remain for the full 12-hour static test, our final visual inspections confirmed that the propulsion system was leak-free and fully operational.
Key Takeaways
Close collaboration with the vessel operators was key to ensuring the successful completion of this project. By adapting to evolving requirements and providing proactive solutions, we minimised downtime and fully restored the vessel’s reliability.
To further expedite the repair process, one of our team members hand-carried critical parts from Holland, ensuring that essential components arrived on-site without delay. This level of commitment and coordination allowed us to identify and address issues early, preventing more significant failures and costly downtime in the future.
This project highlights the value of working closely with vessel operators to deliver efficient, effective, and timely propulsion system repairs. Our expertise in propulsion maintenance ensures vessels remain reliable and operational in even the most demanding conditions.
For more information on how Bartech Propulsion can support you, please visit our homepage or contact us
