=HURRICANE DECK.=--In large steamships a light upper deck extending across the vessel amidships. =HYDRO-AEROPLANE.=--A seaplane. (q.v.) =HYDROPLANE.=--A type of boat the flattened keel of which is so constructed that, after a certain speed has been attained, the hull rises in the water and skims lightly over the surface, thus driving forward _above_ rather than _through_ the water. The hydroplane =cannot= rise into the air and fly. =IDLERS.=--Those, being liable to constant duty by day, who are not required to keep the night watches, such as carpenters, sail-makers, etc., also called “Daymen.” =JACK-STAFF.=--A flagpole for flying the Union Jack, invariably at the bows of the ship. =KEEL.=--That portion of a ship running fore and aft in the middle of a ship’s bottom. =KEEL-PLATE.=--The lowest plate of all in the keel; this plate is the first to be laid down when building is commenced. =KNOT.=--The unit of speed for ships. A ship is said to be going =x= knots, when she is going =x= sea (or nautical) miles in one hour. One sea mile = 6,080 ft. N.B.--The word =knot= should never be used to indicate distance. =KRUPP STEEL.=--Steel hardened by a special process discovered and applied at Essen. =LABOUR.=--When a vessel pitches or strains in a heavy sea she is said to “labour.” =LANDLOCKED.=--Sheltered on all sides by the land. =LARBOARD.=--The old term for port. (q.v.) =LATITUDE.=--Distance north or south of the equator, expressed in degrees. =LAUNCH.=--To place a ship in the water for the first time. =LAY DOWN.=--To commence building a ship. =LEE.=--Or Leeward (pronounced Loo’ard). The side of a vessel opposite to that upon which the wind blows. =LIGHTER.=--A powerful hull or barge with a flat bottom, used for transporting heavy goods, such as coal, ammunition, etc. =LIST.=--A vessel is said to have a list if she heeled temporarily or permanently to one side. =LOG.=--The instrument used to measure a vessel’s speed through the water. Also the ship’s daily journal. =LONGITUDE.=--Distance east or west of a first meridian, expressed in degrees. =MAGAZINE.=--The place on board ship or on shore where ammunition is stored. =MAN.=--To place the right complement of men in a ship or boat to work her. =MARINE.=--A soldier specially trained for sea service. “Soldier and sailor too.” =MAST.=--The tall structure in a ship formerly for the carrying of sail, but now carrying control stations, fighting tops, and wireless telegraphy apparatus. =MASTER.=--The Captain of a merchant vessel who holds a master’s or extra master’s certificate. =MINE.=--A weapon of war which is placed in the sea by the enemy, and explodes on a ship striking it; or can be fired from the shore or ship by means of an electric current. =MINEFIELD.=--A space near a harbour specially devoted to mining operations. =MINE-LAYER.=--A ship specially fitted to lay mines out.