How many fire extinguishers are required aboard an 18-foot powerboat with installed fuel tank(s)?

For an 18-foot powerboat that has installed fuel tanks, the requirement is to have at least one fire extinguisher on board. This guideline is based on safety regulations aimed at ensuring that a vessel is equipped to handle fire hazards, which are particularly concerning when dealing with fuel systems.

The presence of installed fuel tanks increases the risk of fire due to potential leaks or fumes, making it essential to have a fire extinguisher readily accessible in case of an emergency. While larger vessels or those with more complicated systems might require additional extinguishers, for an 18-foot powerboat, one properly rated fire extinguisher is considered sufficient to meet safety compliance.

This requirement also aligns with the recommendations from boating safety organizations, which emphasize preparedness and prompt response in emergency situations. Hence, the correct answer emphasizes the minimal safety standard prescribed for such vessels.