Modern vessels operate in increasingly demanding conditions. Higher efficiency requirements, tighter environmental regulations and extended drydock intervals place significant strain on key ship components. Among the most exposed are rudders, running gear and exhaust gas cleaning systems (ECGS), all of which face continuous mechanical and chemical attack, either below the waterline or from the aggressive nature of the water flowing through them.
Ecoshield, developed by Subsea Industries, is engineered to protect these critical areas for the lifetime of the vessel. This two-part article explores how Ecoshield delivers durable protection against cavitation erosion and corrosion damage, first for rudders and running gear, and then for scrubber systems.
Protecting rudders and running gear
Rudders and running gear are essential to vessel maneuverability, safety and efficiency. Operating in turbulent flow conditions, these components are constantly exposed to cavitation which erodes the coating, leaving the underlying steel exposed to corrosion. Over time, this combination can lead to severe surface damage, reduced hydrodynamic performance and, in extreme cases, structural failure.
Ecoshield has been specifically developed to address these challenges. The coating consists of a thick, glass-platelet reinforced vinyl ester that forms a dense, impenetrable barrier on the steel surface. Once applied, Ecoshield provides long-term resistance to cavitation erosion and corrosion, eliminating the need for repeated recoating during the vessel’s operational life.
Why rudders and running gear need special protection
Cavitation is one of the primary causes of damage to rudders and other underwater appendages. As pressure fluctuations occur around moving components, vapor bubbles form and collapse violently against the steel surface. The resulting micro-impacts progressively remove material, creating pits that grow deeper with time.
Traditional coating systems often struggle to withstand this continuous mechanical assault. Once a coating breaks down, corrosion rapidly develops in the substrate, accelerating damage and increasing repair scope.
Ecoshield addresses this issue through its unique composition. This ensures long-term coating integrity, even in areas subject to extreme hydrodynamic forces. As a result, rudders and running gear retain their original profile and performance characteristics over extended service periods.
Application flexibility and lifecycle benefits
Ecoshield can be applied both during vessel construction and as part of routine drydocking programs. When applied at the newbuild stage, it ensures immediate protection from the first day of operation. For vessels already in service, Ecoshield can be applied following appropriate surface preparation, even when cavitation damage has already occurred.
In cases of existing damage, surfaces can be rebuilt before coating application, using Ecofix, a compatible filler that restores pitted or irregular surfaces, eliminating the need for more costly hot-work repairs.
Over the vessel’s lifetime, this durability delivers significant operational benefits. Reduced coating work during drydockings translates directly into shorter yard stays, lower maintenance costs and increased vessel availability.
Beyond rudders — comprehensive running gear protection
In addition to rudders, Ecoshield is widely applied to other cavitation-prone components, including thruster tunnels, thruster nozzles, stabilizer fins and other propulsion units. By protecting all critical underwater appendages with a single, proven coating system, shipowners can standardize maintenance strategies and achieve consistent long-term performance across the vessel’s underwater profile.
Protecting scrubbers, tanks, pipes and outlet areas
Exhaust gas cleaning systems have become a common feature on many vessels, enabling compliance with global and regional emission regulations while continuing to use the much cheaper heavy fuel oil. While effective in reducing sulphur emissions, scrubbers introduce a highly aggressive internal environment. Acidic washwater, elevated temperatures and continuous flow place extreme demands on the materials and coatings used within these systems.
Key components such as scrubber chambers, internal pipework, recycle tanks and overboard discharge areas are particularly vulnerable to corrosion if not adequately protected.
The corrosive challenge inside scrubbers
The washwater circulating through scrubber systems contains sulphuric acid and chlorides that can rapidly attack unprotected steel. Conventional marine coatings are often unable to cope with these conditions for extended periods, leading to early coating failure and corrosion beneath the film.
Damage is frequently observed not only inside the scrubber system itself, but also at the overboard discharge point and surrounding hull plating. If left unchecked, corrosion in these areas can lead to steel thinning, leaks and increased maintenance requirements, with potential implications for vessel safety and compliance.
Effective protection therefore requires a coating system with exceptional chemical resistance, strong adhesion and long-term stability under continuous exposure.
Ecoshield as a solution for scrubber protection
Ecoshield provides a robust solution for protecting scrubber-related components. The dense, glass-flake reinforced vinyl ester resin forms an impermeable barrier that isolates steel surfaces from aggressive washwater and corrosive compounds. When applied correctly, the coating prevents corrosion from initiating and spreading, even in highly acidic environments.
Ecoshield can be applied to a wide range of scrubber components, including internal pipework, scrubber tanks, washwater chambers, overboard discharge pipes and the hull area surrounding the overboard pipes. The same protective principles apply across all these areas, ensuring consistent performance throughout the scrubber system and protecting the affected hull area.
As with underwater components, correct surface preparation is essential. Once applied, the coating remains stable and intact over long service intervals, reducing the need for inspection and repair.
Lifecycle and operational benefits
The long-term durability of Ecoshield offers clear advantages for scrubber protection. By eliminating frequent recoating cycles, maintenance requirements are significantly reduced, allowing vessel operators to focus on planned maintenance rather than reactive repairs.
Preventing corrosion at an early stage also protects the structural integrity of scrubber systems and surrounding steelwork. This reduces the risk of leaks, unplanned downtime and costly steel repairs, while supporting reliable scrubber operation throughout the vessel’s life.
Where corrosion has already occurred due to the use of inferior or unsuitable coatings, damaged areas can be restored and coated with Ecoshield to halt further degradation, extending the service life of existing installations.
Integrating coating applications into vessel workflows
Ecoshield applications can be seamlessly integrated into scheduled drydockings or retrofit projects. The coating is compatible with standard shipyard practices and does not require complex application procedures. The fact that the coating has a 3-hour minimum overcoat time with no maximum makes its application very flexible. Once in service, its durability reduces future maintenance scope, helping operators optimize drydock planning and minimize vessel downtime.
