pinnace -
A light boat, traditionally propelled by sails, but may also be a rowboat. Pinnaces are usually messenger boats, carrying messages among the larger ships of a fleet.
Wikipedia
A pinnace is one of two marine craft, the first a small vessel used as a tender to larger vessels amongst other things, and the second a ship rigged vessel popular in northern waters through the 17th-19th centuries. The smaller pinnace is a light boat, propelled by sails or oars, formerly used as a "tender" for guiding merchant and war vessels. 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.
