What is the material of the COW main?

• A. Rubber
• B. Plastic
• C. Steel
• D. Copper

Answer: (C)

COW stands for Crude Oil Washing, a system on tankers that uses crude oil to clean the cargo tanks. The main line for this system must be able to handle high flow and pressure, stay chemically compatible with crude oil, and endure the harsh marine environment and fire safety requirements. Steel provides the necessary strength, toughness, weldability, and durability for shipboard cargo and washing lines, making it the standard material for the COW main. Rubber wouldn’t hold up under pressure and exposure to hydrocarbons, and would swell and degrade. Plastic could crack or deteriorate with hydrocarbons and heat, and isn’t relied upon for main cargo piping. Copper lacks the mechanical strength and is not used for large-diameter, high-pressure oil piping aboard ships. So, steel is the appropriate material.