How much foam concentrate must be present with a foam applicator and portable tank?

The requirement for foam concentrate available with a foam applicator and portable tank is, indeed, 20 liters. This quantity is crucial for ensuring that the vessel has an adequate supply to effectively combat a fire, particularly in scenarios involving flammable liquids, where foam is used to suppress vapors and cool the flames.

Knowing the appropriate amount of foam concentrate helps in maintaining compliance with safety regulations, ensuring that the crew is prepared to handle emergency situations effectively. The specified volume also considers the necessary coverage and duration that may be needed during an incident, thus enhancing the overall safety measures on board.

Other options reflect quantities that do not meet the prescribed safety standards and therefore would be insufficient in an emergency situation. Understanding the specifics of these requirements is important for operational readiness and compliance during vessel inspections.