What must officers and crew possess while on duty?

The requirement for officers and crew to possess a current, valid USCG license while on duty is vital for ensuring safe and compliant operation of vessels. The US Coast Guard (USCG) issues licenses to mariners after they meet specific training and experience requirements, which helps confirm that they have the necessary skills and knowledge to perform their duties responsibly.

Holding a valid USCG license signifies that the individual has passed various examinations and fulfilled all necessary regulations, including safety protocols and operational standards. This is crucial in promoting safety on the water, as licensed personnel are well-versed in navigation, seamanship, and emergency procedures. A valid license also helps ensure that individuals are accountable for their actions and can respond appropriately in critical situations, ultimately contributing to the overall safety of the vessel and crew.

The other options, while important in their own right, do not hold the same regulatory requirement under USCG regulations for being on duty as a licensed officer or crew member.