As a ship's boat the pinnace is a light boat, propelled by oars or sails, carried aboard merchant and war vessels in the Age of Sail to serve as a tender.
The pinnace was usually rowed, and could be rigged with a sail for use
in favorable winds. A pinnace would ferry passengers and mail, communicate between vessels, scout to sound anchorages, convey water and provisions, or carry armed sailors for cutting-out expeditions. The Spanish favored them as lightweight smuggling vessels while the Dutch
used them as raiders. In modern parlance, pinnace has come to mean a
boat associated with some kind of larger vessel, that doesn't fit under
the launch or lifeboat definitions.