What is "keel boat"

Keel \Keel\, n. [Cf. AS. ce['o]l ship; akin to D. & G. kiel keel, OHG. chiol ship, Icel. kj[=o]ll, and perh. to Gr. gay^los a round-built Ph[oe]nician merchant vessel, gaylo`s bucket; cf. Skr. g[=o]la ball, round water vessel. But the meaning of the English word seems to come from Icel. kj["o]lr keel, akin to Sw. k["o]l, Dan. kj["o]l.]

1. (Shipbuilding) A longitudinal timber, or series of timbers scarfed together, extending from stem to stern along the bottom of a vessel. It is the principal timber of the vessel, and, by means of the ribs attached on each side, supports the vessel's frame. In an iron vessel, a combination of plates supplies the place of the keel of a wooden ship. See Illust. of Keelson.

2. Fig.: The whole ship.

3. A barge or lighter, used on the Tyne for carrying coal from Newcastle; also, a barge load of coal, twenty-one tons, four cwt. [Eng.]

4. (Bot.) The two lowest petals of the corolla of a papilionaceous flower, united and inclosing the stamens and pistil; a carina. See Carina.

5. (Nat. Hist.) A projecting ridge along the middle of a flat or curved surface.

6. (Aeronautics) In a dirigible, a construction similar in form and use to a ship's keel; in an a["e]roplane, a fin or fixed surface employed to increase stability and to hold the machine to its course. Bilge keel (Naut.), a keel peculiar to ironclad vessels, extending only a portion of the length of the vessel under the bilges. --Ham. Nav. Encyc. False keel. See under False. Keel boat.

   1. A covered freight boat, with a keel, but no sails, used on Western rivers. [U. S.]

   2. A low, flat-bottomed freight boat. See Keel, n., 3.

      Keel piece, one of the timbers or sections of which a keel is composed.

      On even keel, in a level or horizontal position, so that the draught of water at the stern and the bow is the same.
      --Ham. Nav. Encyc.

      On an even keel a. & adv., steady; balanced; steadily.