As to his duties as a watch-officer, it will be necessary to repeat the explanations partly given in the chapter upon the master's duties. The crew are divided equally into two watches, the larboard and starboard; the larboard commanded by the chief mate, and the starboard by the second mate. These watches divide the day between them, being on and off duty every other four hours. This is the theory of the time, but in fact, in nearly all merchant vessels, all hands are kept on deck and at work throughout the afternoon, from one o'clock until sundown; and sometimes, if there is a great deal to be done, as immediately before making port, or after an accident, all hands may be kept throughout the day. This is, however, justly considered hard usage, if long continued, since it gives the men but little time for sleep, and none for reading, or taking care of their clothes. Although all hands may be on deck and at work during a day or a half day, yet the division of time is still kept up. For instance, if it is the mate's watch from 8 A.M. to 12; although all hands should be up from 12 to 5 or 6, yet from 12 to 4 the starboard watch would be considered as 'the watch on deck,' and the larboard again after 4; and so on; and during those hours the wheel will always be taken by men belonging to the watch on deck, and if any particular duty is ordered to be done by 'the watch,' that watch which has a man at the helm, and which would have been the only one on deck had not all hands been kept, would do the duty. But though this division is kept up as to the crew and the helmsman, it is not so as to the officers; for when all hands are on deck, the chief mate is always the officer in command, to whichever watch the hour may properly belong. He accordingly looks out for the ship, takes in and makes sail, and trims the yards, when all hands are on deck at work, as much in the hours of one watch as in those of the other, and he generally calls upon the men of either watch indifferently to pull and haul. But if only the starboard watch is on deck, though the chief mate should be on deck also, yet he will not interfere with the duties of that watch, but would leave the command of the vessel, and the weather side of the quarter-deck, to the second mate. Of course, whenever the master comes on deck, as I have said, in whosever watch it may be, or if all hands are up, he takes the weather side of the quarter-deck, and is considered as having charge of the ship; and the officer of the watch would then give no order with reference to the helm, trimming the yards, making sail, or the like, without a direction from the master.