Midshipmen were expected to work on the ship, but were also expected to learn navigation and seamanship. They were expected to have learned already, as able seamen and volunteers, to rig sails, other duties included keeping watch, relaying messages between decks, supervising gun batteries, commanding small boats, and taking command of a sub-division of the ship's company under the supervision of one of the lieutenants. On smaller ships, midshipmen were instructed by a senior master's mate, often a passed midshipman, who taught them mathematics, navigation, and sailing lore. Larger ships would carry a schoolmaster, who was rated as a midshipman but usually was a civilian like the chaplain. Midshipmen were expected to keep detailed navigational logs, which were shown to the captain to assess their progress.