CALIBRATION-(1) The operation of making an adjustment or marking a scale so that the readings of an instrument conform to an accepted standard. (2) The checking of readings by comparison with an accepted standard.

CALKING-The operation of jamming material into the contact area to make a joint watertight or oiltight.

CASUALTY-An event or series of events in progress during which equipment damage and/or personnel injury has already occurred. The nature and speed of these events are such that proper and correct procedural steps will only serve to limit equipment damage and/or personnel injury.

CAULK-The act of stuffing the seams between wooden planking with oakum for watertightness.

CENTERLINE-(1) Lines that indicate the center of a circle, arc, or any symmetrical object; consist of alternate long and short dashes evenly spaced. (2) The middle line of the ship from stem to stern as shown in any waterline view. (3) Well-defined knife or gage line placed upon the work to serve as a basis from which dimensions are to be measured.

CENTER OF BUOYANCY-The geometric center of gravity of the immersed volume of the displacement or of the displaced water, determined solely by the shape of the underwater body of the ship. It is calculated for both the longitudinal location, forward or aft of the middle perpendicular, and the vertical location above the base line or below the designed waterline.

CENTER OF FLOTATION-The geometric center of gravity of the water plane at which the vessel floats, forward or aft of the middle perpendicular. It is that point about which a vessel rotates longitudinally when actuated by an external force without change in displacement.

CENTER OF LATERAL RESISTANCE- The point through which a single force could act and produce an effort equal to the lateral resistance of the vessel. It is ordinarily assumed to be coincident with the center of gravity of the immersed central longitudinal plane.

CENTER OF PRESSURE-The point in a sail or an immersed plane surface at which the resultant of the combined pressure force acts. Also center of effort.

CENTIGRADE (CELSIUS)-On the centigrade thermometer, the interval between the freezing point and the boiling point of water is divided into 100 parts or degrees, so that 0C. corresponds to 32F., and 100C. to 212F.

CENTRAL CONTROL STATION (CCS)- The main operating station from which a majority of the engineering plant machinery can be controlled and monitored.

CIRCUIT BREAKER (CB)-An automatic protective device that, under abnormal conditions, will open a current-carrying circuit.

CLAMP-A metal fitting used to grip and hold wire ropes. Two or more may be used to connect two ropes in lieu of a short splice or in turning in an eye. Also a device, generally operated by hand, for holding two or more pieces of material together, usually called a "C" clamp. In small boats, the main longitudinal strength member at the side and under the deck beams in decked-over boats, and at the gunwale in open boats.

CLINOMETER-An instrument used for indicating the angle of roll or pitch of a vessel.

COAMING-Bulwark around a hatch opening.

COAMING, BULKHEAD-A term applied to the top and bottom strakes of bulkheads, which are usually made thicker than the remainder of the plating and which act as girder web plates in helping to support the adjacent structure.

COAMING, HATCH-A frame bounding a hatch for the purpose of stiffening the edges of the opening and forming the support for the covers. In a steel ship generally consists of a strake of strong vertical plating completely bounding the edges of a deck opening.

COAMING, HOUSE-A term applied to the narrow vertical plates bounding the top and bottom of a deck house, made somewhat thicker than the side plating and forming a frame for the base and top of the house. Also applied to the heavy timbers which form the foundation of a wood deck house.

COAMING, MANHOLE-The frame worked around a manhole to stiffen the edges of the plating around the opening and to provide a support for the cover.

CO2 INDICATOR-An instrument designed to reveal the presence of carbon dioxide.

COLLISION BULKHEAD-A bulkhead, stronger than normal, located forward to control flooding in the event of a head-on collision.

COMBATANT SHIP-A ship whose primary mission is combat.

COMBUSTIBLE-A material that can burn.

COMPARTMENT-A subdivision of space or room in a ship.

COMPLETE DECK-Any deck which extends the length of a ship and from side to side.

CONFLAGRATION-Large fire with a central column of rising heated air and burned gases, featuring an extended wall of fire moving to leeward in front of a strong wind.

CONSTRUCTION LINES-Lightly drawn lines used in the preliminary layout of a drawing.

CUTOUT VALVE-A valve that is intended normally to be fully open or fully closed.

CUTWATER-The forward edge of the stem at or near the water line is called the cutwater.

DAMAGE CONTROL CONSOLE (DCC)- Located in CCS and provides monitoring for hazardous (fire, high bilge levels, and so forth) conditions. It also monitors the ship's firemain and can control the fire pumps.

DCT-Disaster control team.

DEBALLASTING-The process by which salt water is emptied from tanks to protect the ship from underwater damage and to increase its stability.

DECAY, RADIOACTIVE-Spontaneous and gradual disintegration of one atom or element into another.

DECK-A deck in a ship corresponds to a floor in a building. It is the plating, planking, or covering of any tier of beams above the inner bottom forming a floor, either in the hull or superstructure of a ship. Decks are designated by their location as upper deck, main deck, etc., and forward lower deck, after superstructure deck, etc. The after portion of a weather deck was formerly known as the quarter deck and on warships is allotted to the use of the officers.

DECK BOLT-A special type of bolt used to secure the planks of a wood deck to the frames or deck plating.

DECK, BULKHEAD-The uppermost continuous deck to which all main transverse bulkheads are carried. This deck should be watertight to prevent flooding adjacent compartments if a compartment is holed.

DECK, FREEBOARD-The deck to which the classification societies require the vessel's freeboard to be measured. Usually the upper strength deck.

DECK HEIGHTS-The vertical distance between the molded lines of two adjacent decks.

DECK HOUSE-A term applied to a partial superstructure that does not extend from side to side of a vessel as do the bridge, poop, and forecastle.

DECK PLATING-A term applied to the steel plating of a deck.

DECK STRINGER-The strip of deck plating that runs along the outer edge of a deck.

DEEP TANKS-Tanks extending from the bottom or inner bottom of a vessel up to or higher than the lowest deck. They are fitted with hatches so that they maybe used for cargo when the vessel is loaded in lieu of the ballast water carried when the vessel is' 'light. " They are placed at either end or both ends of the machinery space as deemed necessary.

DEPTH MOLDED-The vertical distance from the molded base line to the top of the uppermost strength deck beam at side, measured and midlength of the vessel.

DESIGNER'S WATERLINE-The intended position of the water surface against the hull.

DESTROYER-A naval vessel of moderate displacement and high speed, armed with rapidfire guns, and torpedo tubes or missiles, used for a protection to capital ships or anti-submarine vessel. Larger vessels of this type are called light cruisers, and smaller vessels are called frigates.

DIAGONAL LINE-A line cutting the body plan diagonally from the frames to the middle line in the loft lay-out and usually a mean normal to a group of frames of similar curvature, representing a plane introduced for line fairing purposes.

DISPLACEMENT CURVES-Curves drawn to give the displacement of the vessel at varying drafts, Usually these curves are drawn to show the displacement in either salt or freshwater, or in both, the saltwater curves being based on 35 cubic feet to a ton and freshwater curves on 36 cubic feet to a ton. Corrections are made from these basic standards for variable density of the water.

DISPLACEMENT, DESIGNED-The displacement of a vessel when floating at her designed draft.

DISPLACEMENT, FULL LOAD-The displacement of a vessel when floating at her greatest allowable draft as established by the classification societies. In warships an arbitrary full-load condition is established.

DISPLACEMENT, LIGHT-The displacement of the vessel complete with all items of outfit, equipment, and machinery on board but excluding all cargo, fuel, water, stores, passengers, dunnage, and the crew and their effects. Naval and merchant practice differs in one particular; in the former the machinery weights are dry, while the merchant light condition includes the water and oil in the machinery with boilers at steaming level.

DOG-(1) A lever, or bolt and screws, used for securing a watertight door, hatch, or port. (2) A device used to secure stock to the rotating parts of a lathe.

DOGDOWN-TO set the dogs on a watertight door.

DOGGING-(1) The act of securing a hatch or cover with dogs. (2) The act of dividing a 4-hour watch into two shorter watches. See also "dog down."

DOOR FRAME-The frame surrounding a door opening on which the door seats.

DOOR, JOINER-A light door fitted to staterooms and quarters where air and watertightness is not required. Made of wood, light metal, and metal-covered wood. Metal joiner doors with pressed panels are extensively used.

DOOR, WATERTIGHT-A door so constructed that, when closed, it will prevent water under pressure from passing through. A common type consists of a steel plate, around the edges of which a frame or angle bar is fitted, having a strip of rubber attached to the reverse side of the flange that is fastened to the door plate. The strip of rubber is compressed against the toe of the flange of an angle-iron door frame by dogs or clamps.

DOUBLE BOTTOM-A term applied to the space between the inner and outer skins of a vessel called respectively the "inner bottom" and "shell," usually extending from bilge to bilge and for nearly the whole length of the vessel fore and aft, and subdivided into water or oiltight compartments. In some cases, and generally in warships, the inner bottom is carried above the bilges to a deck at or near the waterline. Where more than one inner skin is fitted, as is sometimes the case, the two spaces are known as the "lower bottom tank" or "void" and the ^{"upper bottom tank."} The outer skin is known ^{as the "shell,"} the skin next to it as the ^{"lower inner bottom,"} and the third skin as the "upper inner bottom."

DRAFT-(1) The depth of the vessel below the waterline measured vertically to the lowest part of the hull, propellers, or other reference point. When measured to the lowest projecting portion of the vessel, it is called the "draft, extreme", when measured at the bow; it is called "draft, ^forward"; and when measured at the stern, the "draft, aft"; the average of the draft, forward, and the draft, aft, is the "draft, mean," and the mean draft when in full load condition is the ^{"draft, load." (}2) (Foundry term) The angle of slant tending away from the line of parting given to those surfaces of a pattern which would lie in the direction in which the pattern or its component parts are drawn from the sand.

DRAFT MARKS-The numbers which are placed on each side of a vessel near the bow and stern, and often also amidships, to indicate the distance from the number to the bottom of the keel or a fixed reference point. These numbers are six inches high, are spaced twelve inches bottom to bottom vertically, and are located as close to the bow and stern as possible.

DRAG-(1) The designed excess of draft, aft, over that forward, measured from the designer's waterline. The drag is constant and should not be confused with trim. (2) Resistance to ships forward motion caused by skin friction. _{(3) Foundry term;} The bottom section of a molder's flask.