(nautical) A type of keel common in sailing yachts, its shape resembling the fin of a fish.

Alternative spelling of keelhaul

plural of caudal keel

plural of bilge keel

(nautical) a strake, or small keel or blister, running along much of the length of the hull. It is used to reduce the hull's tendency to roll. They are typically fitted one on each side, low down on the side of the hull, so as not to increase the draft of the vessel. In battleships they were often quite large and used as part of the torpedo protection system.

(intransitive, nautical, also figuratively) Of a vessel: to roll so far on its side that it cannot recover; to capsize or turn turtle.

(ichthyology) A lateral ridge found just anterior to each side of the tail fin on the caudal peduncle of some types of fast-swimming fish. The keels improve the stability of the fish's attitude at speed in the water, and strengthen the support of the caudal fin.

(nautical) The situation in which a watercraft is floating or proceeding in a smooth and level manner. / (idiomatic, of emotions, etc.) The state or characteristic of being under control and balanced.

Alternative spelling of even keel

(nautical) Having the keel arched upwards, but not actually hogged.