What document must be presented upon request during a vessel boarding?

The requirement for a vessel's documentation or registration to be presented upon request during a boarding is based on maritime regulations that aim to ensure compliance with laws governing vessel operation. Documents such as the vessel's documentation or registration provide essential information about the vessel's ownership, home port, and the validity of its operation. This documentation is crucial for boarding officers to verify that the vessel is legally registered, which conforms with both national and international maritime laws.

In contrast, while insurance policy documents may be important in terms of financial responsibility, they are not typically mandated to be produced during a routine boarding. Similarly, a ship's manifest and a passenger guest list are not universally required and may only be relevant under specific circumstances or for certain types of vessels. The vessel's primary documentation is essential for establishing its legal status, making it the key document that must be presented in the context of a vessel boarding.