[…] I had my Man Friday to teach as to what belong'd to the Navigation of my Boat; for though he knew very well how to paddle a Canoe, he knew nothing what belong'd to a Sail and a Rudder, and was the moſt amaz'd when he ſaw me work the Boat too and again in the Sea by the Rudder, and how the Sail gyb'd, and fill'd this Way or that Way, as the Courſe we ſail'd chang'd: […]
Source: wiktionary