Which ABYC standard is best for addressing fire protection on boats?

The correct choice is A-4, which is the standard that specifically addresses fire protection on boats. This standard provides guidelines for the installation and maintenance of fire safety systems, including fire extinguishers, alarms, and materials used in construction that reduce fire risk. It focuses on preventing fire hazards and ensuring that safety measures are in place to protect both the vessel and its occupants in the event of a fire.

In the context of the other choices, E-11 pertains to electrical systems, specifically ensuring that electrical installations do not pose a fire risk but is not solely focused on fire protection. A-27 relates to the standards for marine systems involving fuel systems, which also contribute to fire safety indirectly but do not cover fire protection comprehensively. H-23 deals with heating and cooling systems on boats and is more about environmental comfort rather than explicit fire safety measures. Thus, while all these standards contribute to overall marine safety, A-4 is the most relevant to direct fire protection on boats.