A gunboat is literally a boat carrying one or more guns. The term is rather broad, and the usual connotation has changed over the years (sometimes encompassing vessels which would otherwise be considered ships). History Age of sail In the age of sail, a gunboat was usually a small undecked vessel carrying a single smoothbore cannon in the bow, or just two or three such cannons. A gunboat could carry one or two masts or be oar-powered only, but the single-masted version of about 50 ft length… (More on Gunboats)