This document outlines regulations regarding watchkeeping arrangements and principles to ensure safe watches on ships. It addresses requirements for fitness for duty, including establishing rest periods to prevent fatigue. It provides guidance on watch schedules, records of hours of rest, and limits on alcohol consumption for watchkeeping personnel. It also describes principles for proper watchkeeping, including roles and responsibilities of watchkeeping officers and crew, exchanging of information, and notifying superiors if in doubt. Requirements are established for engineering watch composition and responsibilities of officers in charge of the engineering watch for machinery operation and maintenance.