Keel in the context of "Sailboat"

Sailing into the wind is a sailing expression that refers to a sail boat's ability to move forward despite heading toward, but not directly into, the wind. A sailboat cannot sail directly into the wind; the closest it can point is called close hauled, typically at an angle of about 45 degrees to the wind.

This maneuver is possible due to the interaction between the sails and the keel. The sail generates lift (similar to an airplane wing), and the keel resists lateral movement through the water, converting the side force from the wind into forward motion. Although the sail force acts partly sideways, the keel’s counteracting force keeps the boat on course and propels it forward.

Lashed-lug boats are ancient boat-building techniques of the Austronesian peoples. It is characterized by the use of raised lugs (also called "cleats") on the inner face of hull planks. These lugs have holes drilled in them so that other hull components such as ribs, thwarts or other structural components can be tied to them with natural fiber ropes (hence "lashed"). This allows a structure to be put together without any metal fastenings. The planks are further stitched together edge-to-edge by sewing or using dowels ("treenails") unto a dugout keel and the solid carved wood pieces that form the caps for the prow and stern. Characteristically, the shell of the boat is created first, prior to being lashed unto ribs. The seams between planks are also sealed with absorbent tapa bark and fiber that expands when wet or caulked with resin-based preparations.

Lashed-lug construction has been used on a wide size range of vessels, from small craft, such as logboats that have had planks added to their sides to increase their freeboard, to large plank-built ships. It is found in traditional boats of Maritime Southeast Asia, Melanesia, Madagascar, Micronesia, and Polynesia. It forms part of the maritime technology used by Austronesian peoples in their spread throughout the islands of the Indo-Pacific starting at 3000 to 1500 BCE. The oldest recovered remains of ships of lashed-lug construction is the Pontian boat of Malaysia dated to at around c.260–430 CE.

The draft or draught of a ship is a determined depth of the vessel below the waterline, measured vertically to its hull's lowest—its propellers, or keel, or other reference point. Draft varies according to the loaded condition of the ship. A deeper draft means the ship will have greater vertical depth below the waterline. Draft is used in under keel clearance calculations, where the draft is calculated with the available depth of water (from Electronic navigational charts) to ensure the ship can navigate safely, without grounding. Navigators can determine their draught by calculation or by visual observation (of the ship's painted load lines).

In "Jackspeak" (Royal Navy slang), it also refers to the dress uniform of Junior Ratings.

A fore-and-aft rig is a sailing ship rig with sails set mainly in the median plane of the keel, rather than perpendicular to it, as on a square-rigged vessel.

Viking ships were marine vessels of unique structure, used in Scandinavia throughout the Middle Ages. The boat-types were quite varied, depending on what the ship was intended for, but they were generally characterized as being slender and flexible boats, with symmetrical ends with true keel. They were clinker built, which is the overlapping of planks riveted together. Some might have had a dragon's head or other circular object protruding from the bow and stern for design, although this is only inferred from historical sources. Viking ships were used both for military purposes and for long-distance trade, exploration and colonization.

In the literature, Viking ships are usually seen divided into two broad categories: merchant ships and warships, the latter resembling narrow "war canoes" with less load capacity but higher speed. However, these categories are overlapping; some transport ships would also form part of war fleets. As a rule, ship lanes in Scandinavia followed coastal waters, hence a majority of vessels were of a lighter design, while a few types, such as the knarr, could navigate the open ocean. The ship's shallow draft allowed navigation in waters only one meter deep and permitted beach landings, while its light weight enabled it to be carried over portages. The Viking ships ranged from the Baltic Sea to far from the Scandinavian homelands, to Iceland, the Faroe Islands, Greenland, Newfoundland, the Mediterranean, the Black Sea and Africa.