APPENDIX I GLOSSARY

ADHESION-The molecular attraction exerted between the surfaces of bodies in contact.

ADJUSTMENT-To change the physical characteristics of an instrument to make it more accurate.

AFT-Near the stern; toward the stern. Not as specific as abaft.

AFTER-That which is farthest aft, as after fireroom.

AFTER BODY-That portion of a ship's body aft of the midship section.

AFTER PERPENDICULAR-A line perpendicular to the baseline intersecting the after edge of the stern post at the designed waterline. On submarines or ships having a similar stern, it is a vertical line passing through the point where the designed waterline intersects the stern of the ship.

AIR PORT-An opening in the side or deck house of a vessel, usually round in shape and fitted with a hinged frame in which a thick glass is secured. The purpose of the air port is to provide light and ventilation to and vision from the interior of the ship. In some instances the air port is also provided with an additional solid metal hinged cover for purposes of protection of the interior should the glass be damaged or to prevent light from showing from within.

AMBIENT-Surrounding, environmental

(for example, ambient temperature refers to the temperature surrounding an instrument).

AMIDSHIPS-An indefinite area midway between the bow and the stern. Rudder amidships means that the rudder is in line with the ship's centerline.

AQUEOUS FILM FORMING FORM (AFFF)-A light chemical that, when mixed with seawater, produces a fire-extinguishing foam that covers a liquid fire and separates the fire from its oxygen supply.

ARMORED DECK-A deck, below the main deck, that provides added protection to vital spaces.

ASTERN-Signifying position, in the rear of or abaft the stern; as regards motion the opposite of going ahead; backwards. Directly behind a ship.

ATHWARTSHIP-Reaching across a vessel, from side to side.

ATMOSPHERE-A unit of measure equal to 14.696 psi or 29.92 inches of mercury (e.g. 1 atmosphere = 14.696 psi).

ATMOSPHERIC PRESSURE-The pressure of air at sea level, approximately 14.7 pounds per square inch.

AUTOMATIC BUS TRANSFER (ABT)- Normal and alternate power sources are provided to vital loads. These power sources are supplied from separate switchboards through separated cable runs. Upon loss of the normal power supply, the ABT automatically disconnects this source and switches the load to the alternate source.

BACK PRESSURE-(1) Refers to the resistance to the flow of exhaust fluids through the exhaust system. (2) The pressure exerted on the exhaust side of a pump or engine.

BALLAST-Any weight carried solely for the purpose of making the vessel more worthy. Ballast may be either portable or fixed, depending upon the condition of the ship. Fixed or permanent ballast in the form of sand, concrete, lead, scrap, or pig iron is usually fitted to overcome an inherent defect in stability or trim due to faulty design or change character of service. Portable ballast, usually in the form of water pumped into or out of the bottom, peak, or wing ballast tanks, is utilized to overcome a temporary defect in stability or trim due to faulty loading, damage, etc., and to submerge submarines.

BALLASTED CONDITION-A condition of loading in which it becomes necessary to fill all or part of the ballast tanks in order to secure proper immersion, stability, and steering qualities brought about by consumption of fuel, stores, and water or lack of part or all of the designed cargo.

BALLASTING-The process of filling empty tanks with saltwater to protect the ship from underwater damage and to increase its stability. See DEBALLASTING.

BALLAST TANKS-Tanks provided in various parts of a ship for introduction of water ballast when necessary to add weight to produce a change in trim or in stability of the ship, and for submerging submarines.

BALLAST WATER-Seawater, confined to double bottom tanks, peak tanks and other designated compartments, for use in obtaining satisfactory draft, trim, or stability.

BATTEN-(1) Long, thin, strips of wood, steel, or plastic, usually of uniform rectangular section used in the drafting room and mold loft to lay down the lines of a vessel, but sometimes thinned down in the middle or at the ends to take sharp curves. A strip of wood or steel used in securing tarpaulins in place. To secure by means of battens, as to "batten down a hatch." (2) Wooden bar or strip fastened to patterns to hold them straight or to prevent distortion through the ramming of the mold.

BATTEN DOWN-The act of applying battens to a hatch. Extended to mean the closing of any watertight fixture.

BATTENS, CARGO-A term applied to the wood planks or steel shapes that are fitted to the inside of the frames in a hold to keep the cargo away from the shell plating; the strips of wood or steel used to prevent shifting of cargo.

BATTENS, SEAM-Wood seamstraps which connect the edges of small boats having a single thickness of planking. They give additional stiffness to the plank, are continuous, and frames are notched out to fit over them.

BATTLESHIP-A naval vessel having a large displacement, good speed, large radius of action, maximum armament, maximum protection against gun fire, bombs, and torpedoes, ability to keep at sea in all weathers and to bear the brunt of sea fighting as a line-of-battle ship.

BEAM-The extreme width of a ship. Also an athwartship or longitudinal member of the ship's structure supporting the deck.

BEAM, TRANSOM-A strong deck beam situated in the after end of the vessel connected at each end to the transom frame. The cant beams which support the deckplating in the overhang of the stern are attached to and radiate from it.

BETWEEN DECKS-The space between any two, not necessarily adjacent, decks. Frequently expressed as "Tween Decks."

BILGE-(1) Bottom of the hull near the keel; (2) To fail an examination; (3) Bilge water is foul water, so to apply the term to oral or written statements implies that the statement is worthless. (4) To open a vessel's lower body to the sea.

BILGE KEEL-A keel attached to the outside of a ship's hull, near the turn of the bilge, to reduce rolling.

BILGE PLATES-The curved shell plates that fit the bilge.

BILGES-The lowest portion of a ship inside the hull, considering the inner bottom where fitted as the bottom hull limit.

BOLT-A metal rod used as a fastening. With few exceptions, such as drift bolts, a head or shoulder is made on one end and a screw thread to carry a nut is cut on the other,

BOOT TOPPING-An outside area on a vessel's hull from bow to stern between certain waterlines to which special air, water, and grease-resisting paint is applied; also the paint applied to such areas.

BORDER LINES-Dark lines defining the inside edge of the margin on a drawing.

BOSS-(1) The curved, swelling portion of the ship's underwater hull around the propeller shaft. (2) A projection on a casting of circular cross section.

BOSS PLATE-The plate that covers the boss.

BOTTOM-That portion of a vessel's shell between the keel and the lower turn of the bilge.

BOTTOM BOARD-A rough board similar to a molding board upon which the finished mold rests.

BOTTOM, OUTER-A term applied to the bottom shell plating in a double bottom ship.

BOTTOM PLATING-That part of the shell plating which is below the water line. More specifically, the immersed shell plating from bilge to bilge.

BREADTH, EXTREME-The maximum breadth measured over plating or planking, including beading or fenders.

BREADTH, MEASURED-Measured amidships at its greatest breadth to outside of plating.

BREADTH, MOLDED-The greatest breadth of the vessel measured from heel of frame on one side to heel of frame on other side.

BREAK OF FORECASTLE or POOP-The point at which the partial decks known as the forecastle and poop are discontinued.

BULKHEAD-A term applied to any one of the partition walls which subdivide the interior of a ship into compartments or rooms. The various types of bulkheads are distinguished by the addition of a word or words, explaining the location, use kind of material or method of fabrication, such as fore peak, longitudinal, transverse, watertight, wire mesh, pilaster, etc. Bulkheads which contribute to the strength and seaworthiness of a vessel are called strength bulkheads, those which are essential to the watertight subdivision are watertight or oiltight bulkheads, and gastight and fumetight bulkheads serve to prevent gas or fumes from leaving or entering certain parts of a vessel. Never called a wall.

BULKHEAD, AFTER PEAK-A term applied to the first transverse bulkhead forward _{of the stern post.} This bulkhead forms the forward boundary of the after-peak tank and should be made watertight.

BULKHEAD, COLLISION-The foremost transverse watertight bulkhead in a ship which extends from the bottom of the hold to the freeboard deck. It is designed to keep water out of the forward hold in case of collision damage. Usually, this is the fore peak bulkhead at the after end of the fore peak tank.

BULKHEAD, JOINER-Wood or light metal bulkheads serving to bound staterooms, offices, etc. and not contributing to the ship's strength. Included under this head are corrugated metal, pressed panel, pilaster, aluminum, stainless steel, etc.

BULKHEAD STIFFENER-Members attached to the plating of a bulkhead for the purpose of holding it in a plane when pressure is applied to one side. The stiffener is generally vertical, but horizontal stiffeners are used and both are found on same bulkheads. The most efficient stiffener is a T section; flat bars, angles, channels, zees, H and I sections are commonly used.

BULKHEAD, SWASH-A strongly built, nontight bulkhead placed in oil or water tanks to slow down the motion of the fluid set up by the motion of the ship.

BULKHEAD, WIRE MESH-A partition or enclosure bulkhead, used largely in store rooms, shops, etc., made of wire mesh panels.

BUOYANCY-Ability to float; the supporting effort exerted by a liquid (usually water) upon the surface of a body, wholly or partially immersed in it.

BUOYANCY, RESERVE-The floating or buoyant power of the unsubmerged portion of the hull of a vessel. Usually referred to a specific condition of loading.

BYPASS-To divert the flow of gas or liquid. Also, the line that diverts the flow.