keelboats

A keelboat is a boat that has a fixed keel. In sailing use, the keel is a ballast-filled or weighted appendage on the bottom of the hull that provides stability, righting moment, and improved tracking when sailing, especially upwind. Keelboats can be small day sailors as well as larger cruising or racing yachts.

Fixed keels give advantages over boats with retractable fins or centerboards: they resist sideways motion (leeway) and allow a heavier ballast, which lowers the center of gravity and improves stability in heavier seas. Keels may be designed in several forms, including full keels that run along a large portion of the hull, compact fin keels, or keels with ballast bulbs. Draft ranges vary from shallow to deep, affecting suitability for different waters. Sail plans and hull shapes vary accordingly.

In historical contexts, the term keelboat was also used for inland-waterway cargo vessels on the United States rivers in the 19th century. These boats were typically long and shallow-draft, designed to carry large loads with propulsion by oars and sails, and they relied on their keel or keel-like structure for stability and steering. The rise of steamboats and other more maneuverable cargo craft led to the decline of traditional keelboats in commercial service.