Which enforcement option can lead to immediate vessel actions?

The enforcement option that allows for immediate vessel actions can include all the choices listed. Each of these enforcement mechanisms can have a direct and prompt impact on the vessel's operation.

A warning letter serves as a formal notification of compliance issues, which may motivate the vessel's operator to take immediate corrective actions to avoid further repercussions.

Voyage termination is a more severe measure that results in the immediate cessation of the vessel's operation until issues are resolved. This action is particularly immediate and disruptive, underscoring the urgency in addressing compliance failures.

A notice of violation can also prompt immediate actions as it formally outlines the infringements and often specifies the need for corrective measures to continue operations without additional penalties.

Thus, all of these enforcement options are designed to promote compliance swiftly and effectively, which is crucial for maintaining safety and regulatory standards on the water.