What is the primary purpose of a fire extinguisher on board a boat?

The primary purpose of a fire extinguisher on board a boat is to extinguish fires and ensure safety. In the event of a fire, having a fire extinguisher readily available enables immediate action to control or eliminate the fire, which is crucial in the confined space of a boat where fires can escalate quickly and pose serious danger to both life and property.

Boats often have unique fire hazards due to the presence of fuel, electrical systems, and various flammable materials, making it essential to have accessible and operational fire extinguishing equipment. Therefore, the correct answer reflects the importance of having effective fire safety measures in place to protect passengers, crew, and the vessel itself.

On the other hand, the other options do not serve the practical safety needs that a fire extinguisher provides. While decoration may add aesthetic appeal to a boat, it does not contribute to safety. Signaling for help is typically done through other means, such as flares or radios, and cooling down the engine is a separate maintenance function that does not relate to fire safety directly. Hence, the selection of the first option aligns with the fundamental safety regulations and practices in marine environments.