Marine cylinders are specifically built to resist extreme corrosion caused by constant exposure to saltwater and sea air.

Corrosion-resistant materials: Manufacturers use specialty alloys like stainless steel, nickel alloys, or titanium for the cylinders.

Enhanced coatings: Piston rods are protected with advanced coatings, such as nickel-chrome, HVOF (High-Velocity Oxygen Fuel), or special laser-cladded alloys, that provide superior corrosion and abrasion resistance.

Marine-grade paint: External surfaces are often coated with thick, multi-layer, marine-grade paint (e.g., C5 ISO-12944 compliant) to provide additional protection. 

Sealing and bearing systems

The sealing system is crucial for preventing contaminants like saltwater from entering and hydraulic fluid from leaking out, both of which can cause system failure. 

Redundant and robust seals: Cylinders use multiple, specialized seals, exclusion seals, and scrapers to withstand constant exposure to harsh elements.

Advanced materials: Seals are often made of specialized compounds that are resistant to saltwater, aggressive fluids, and a wide range of temperatures.

Self-lubricating bearings: Oversized, corrosion-resistant, and self-lubricating bearings are used in mounting points to handle heavy, dynamic side loads and minimize friction. 

Safety and control features

The reliability of these cylinders is paramount to safety in offshore and marine environments.

Position sensing: Many marine cylinders are equipped with integrated position measuring systems, proximity sensors, and pressure transducers to provide operators with real-time feedback for precise control.

Integral safety functions: Features like hydraulic lockouts or integrated valve technology are built directly into the cylinder to hold a load safely, even in the event of hydraulic system failure.

Certification: Cylinders designed for the marine industry must meet the strict safety and quality standards of international classification societies like ABS (American Bureau of Shipping) or DNV-GL.