What is the purpose of a vapor control system on a tank vessel?

The purpose of a vapor control system on a tank vessel is to control cargo vapor emissions during loading and ballasting. This system is crucial for preventing the release of harmful vapors into the atmosphere, which not only complies with environmental regulations but also enhances safety by reducing the risk of explosion and fire.

When a cargo tank is filled, the vapor produced must be managed to avoid over-pressurization and to minimize emissions. The vapor control system captures these vapors, directing them to a collection system or a treatment facility, rather than allowing them to escape directly into the atmosphere. This helps maintain a safer operating environment and aligns with regulatory requirements aimed at protecting air quality.

The other options address different aspects of vessel operation but do not directly pertain to the primary function of the vapor control system, which focuses specifically on managing vapors emitted during the loading and ballasting processes.