In commercial or military vessels, approximately one sailor per 10 tons of displacement is required. For example, a Venetian cocca: 240 tons with 20 adult sailors and 8 apprentices, by law. In the 13th century, a lateen-rigged ship was 240 tons with 50 men. In the 17th century, the ratio returned to one man per 5 tons in English Mediterranean shipping, but the increase was to defend against pirates.
