What primary document must every vessel carry?

Every vessel is required to carry ship's registry or documentation papers as this primary document serves crucial legal and administrative purposes. The ship's registry verifies the vessel's nationality and indicates where it is legally registered, which is essential for establishing the ship's ownership and compliance with international maritime laws. This document provides evidence of the vessel's compliance with safety and operational regulations and is often necessary for port entry and customs clearance.

Other documents, while important for specific functions, do not fulfill the same comprehensive role. The ship's logbook is essential for recording the daily operations and activities of the ship. The insurance certificate proves financial coverage in case of accidents or damages but does not establish the vessel's legal standing. Nautical charts are critical for navigation, but they do not serve as a legal document like the ship's registry or documentation papers.