Which document must be maintained by tank vessels to record oil transfer operations?

The Oil Record Book is a crucial document that tank vessels are required to maintain to accurately record all oil transfer operations. This includes loading, unloading, and operational discharges of oil, as stipulated by MARPOL Annex I regulations. The purpose of the Oil Record Book is to ensure that all transactions related to oil handling are documented, allowing for accountability and compliance with environmental regulations to prevent oil pollution.

Maintaining this record is essential to demonstrate that the vessel is following best practices regarding oil handling and that it has not engaged in practices that could lead to oil spills. The entries in the Oil Record Book provide evidence that can be reviewed during inspections by authorities, including the USCG during Port State Control examinations, to verify adherence to international standards.

Other documents, while important for various reasons, do not specifically serve the purpose of tracking oil transfer operations. The ship's log may contain general information about the vessel's operations, the cargo manifest lists the cargo onboard, and the ballast water record book is focused on managing ballast water, which is separate from oil transfer processes. Hence, the Oil Record Book is the definitive document required for this particular function.