Cavitation Repair and Protection of Coastal Sathwa Vessel’s Stern Pipe
In the maritime industry, corrosion control is a constant challenge, especially for vessels exposed to harsh seawater environments. This case study covers the successful repair and protection of the stern pipe of the Coastal Sathwa vessel, demonstrating the importance of advanced repair materials and processes.
Corrosion & cavitation challenge
The stern pipe of the Coastal Sathwa experienced significant pitting corrosion, which is common in submerged metal parts of vessels due to constant exposure to seawater. The affected surface had approximately 150-200 pits with depths ranging from 1-3 mm. Pitting, if not addressed promptly, can escalate to severe structural damage, impacting vessel safety and performance.
Solution and Approach
The repair strategy focused on pit filling, surface rebuilding, and protective coating. The following products were used:
Belzona 1311 (Ceramic R-Metal): A two-component epoxy used for rebuilding the pitted surface. It features a paste-grade system suitable for filling and leveling eroded metal areas, restoring the surface to its original contour.
Belzona 1321 (Ceramic S-Metal): This two-component epoxy coating was applied after surface preparation to provide corrosion and erosion resistance. It is designed for continuous immersion in seawater and offers a solvent-free, highly durable protective layer.
Application Procedure
The application process involved meticulous surface preparation and coating:
Surface Preparation: Achieved using SA 2.5 grit blasting, followed by cleaning and degreasing to ensure a contaminant-free substrate. This stage is crucial to maximize adhesion of the repair and coating materials.
Rebuilding Phase: Belzona 1311 was applied to fill the pits, reshaping the metal surface. After curing, the surface was smoothened for the next phase.
Coating Phase: After surface frost blasting (20-50 microns), Belzona 1321 was applied uniformly, ensuring complete coverage and the specified thickness to withstand the marine environment.
The Outcome
The repair was completed within a single day, demonstrating efficient use of resources and time. Post-application inspections confirmed that the restored stern pipe met performance expectations, with enhanced protection against future corrosion and erosion.
Key Takeaways
- Material Choice: Selecting high-performance epoxy systems like Belzona 1311 and 1321 ensures lasting protection and reduces maintenance frequency.
- Surface Preparation: Proper surface preparation is crucial for effective adhesion and long-term durability of the protective coatings.
- Efficiency: The project was completed within 24 hours, demonstrating the effectiveness of fast-curing materials in critical ship repair applications.
Final Thoughts
The successful rehabilitation of the Coastal Sathwa’s stern pipe highlights how proactive corrosion management can extend the life of maritime assets, reduce downtime, and improve safety. By using innovative epoxy solutions and adhering to best practices in surface preparation and application, we achieved a reliable, long-term repair solution.
If you have similar challenges or would like to discuss how advanced polymer technologies can benefit your projects, feel free to connect or leave a comment below!