Which term describes a device that prevents low voltage DC galvanic current flow while allowing the passage of AC current?

The correct choice refers to a Galvanic Isolator, which is specifically designed to achieve the function described in the question. A Galvanic Isolator incorporates diodes or transformer technology to block low voltage direct current (DC) flows, effectively preventing galvanic corrosion. Galvanic corrosion occurs when dissimilar metals are in an electrolyte, which can be an issue in marine environments where metal parts are often submerged or in contact with water.

By allowing alternating current (AC) to pass while blocking unwanted DC current, a Galvanic Isolator protects vessels from the adverse effects caused by galvanic current, which can lead to increased wear and degradation of metal components. Thus, its functionality is crucial for maintaining the longevity and integrity of marine electrical systems.

The other terms provided do not match this specific functionality. For example, a Current Regulator typically manages the amount of current flowing in a circuit but does not specifically address galvanic currents or the need to isolate. A Power Divider can redistribute power among various circuits but does not focus on preventing low voltage DC flow. Finally, Galvanic Control implies a more generic control over galvanic issues, without the explicit current isolation function that a Galvanic Isolator provides.