Which statement best describes a simplex sea strainer?

• A. A single element to strain the sea water
• B. Two elements with a valve to direct flow
• C. A continuous multi-element filter without valves
• D. A self-cleaning device with multiple stages

Answer: (A)

In a simplex sea strainer, the defining idea is one filtering element in the flow path. This means all seawater passes through a single screen before reaching the pump, with no valves to switch between elements and no self-cleaning or multi-stage setup. That plain, single-element configuration is what the term "simplex" conveys. The other options describe more complex arrangements—two elements with a flow-directing valve (duplex), a multi-element filter without valves, and a self-cleaning, multi-stage device—so they don’t fit the simplex description.