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A B C D E F
G H I J K L
M N O P Q R
S T U V W X  Y  Z


--S--

SAFETY TREADS
A special nonslipping metal plate fitted to the deck at the foot of a ladder or stairway and often fitted on the upper surface of the steps of ladders and stairs. Steps made of safety treads are called safety steps.
SAGGING
The deformation or yielding caused when the middle portion of a structure or ship settles or sinks below its designed or accustomed position. The reverse of hogging.
SAIL TRACKS
A device fitted on the after side of a mast in which slides, secured to the forward edge of a fore-and-aft sail, travel up and down the mast as the sail is hoisted or lowered; used in lieu of mast hoops.
SAMSON POST
A strong vertical post that supports cargo booms. See king posts.
SCANTLINGS
A term applied to the dimensions of the frames, girders, plating, etc., that enter into a ship's structure.
SCARF
An end connection made between two pieces of material by tapering them so that they will fit together in a joint of the same breadth and depth as the pieces.
SCREEN BULKHEAD
A light bulkhead used as a shelter from an excess of heat, cold, or light, or to conceal something from sight.
SCRIEVE BOARD
A large board made of soft, clear, planed lumber, sometimes a section of the mold loft floor, on which a full-sized body plan of a ship is drawn. The lines were formerly cut in by the use of a scriving knife, which made a small U-shaped groove, to prevent them from being obliterated. Pencil lines have taken the place of cutting to a large extent. It is used in making templates of frames, beams, floors, etc., and in taking off dimensions. It is sanded smooth after it has served its purpose.
SCUPPER PIPE
A pipe conducting the water from a deck scupper to a position where it is discharged overboard.
SCUPPERS
Drains from decks to carry off accumulations of rain water or sea water. The scuppers are placed in the gutters or waterways on open decks and in corners of enclosed decks, and connect to pipes leading overboard.
SCUTTLE
A small opening, usually circular in shape and generally fitted in decks to provide access. Often termed escape scuttles, and when fitted with means whereby the covers can be removed quickly to permit exit, are called quick acting scuttles.
SCUTTLE BUTT
The designation for a container of the supply of drinking water for the use of the crew.
SEA CHEST
An arrangement for supplying sea water to condensers and pumps, and for discharging waste water from the ship to the sea. It is a cast fitting or a built-up structure located below the waterline of the vessel and having means for attachment of the piping. Suction sea chests are fitted with strainers or gratings.
SEA COCK, SEA CONNECTION
A sea valve secured to the plating of the vessel below the waterline for use in flooding tanks, magazines, etc., to supply water to pumps, and for similar purposes.
SEAM
A term applied to an edge joint.
SEAMSTRAP
A term applied to a strip of plate serving as a connecting strap between the butted edges of plating. Strap connections at the ends are called buttstraps.
SEARCHLIGHT
A powerful electric lamp placed at the focus of a mirror, which projects the light in abeam of parallel rays.
SET IRON
A bar of soft iron used on the bending slab as a form to which to bend frames into the desired shape.
SERVE
To wrap any small stuff tightly around a rope which has been previously wormed and parcelled. Very small ropes are not wormed.
SET, PERMANENT SET
The permanent deformation resulting from the stressing of an elastic material beyond its elastic limit.
SETSCREW
A machine screw with either a slotted or a square head used to hold a part in place.
SET UP
To tighten the nut on a bolt or stud; to bring the shrouds of a mast to a uniform and proper tension by adjusting the rigging screws or the lanyards through the dead eyes.
SHACKLE BOLT
A pin or bolt that passes through both eyes of a shackle and completes the link. The bolt may be secured by a pin through each end, or a pin through one end and through the eye, or by having one end and one eye threaded or one end headed and a pin through the other.
SHAFT, SHAFTING
The cylindrical forging, solid or tubular, used for transmission of rotary motion from the source of power, the engine, to the propellers.
SHAFT ANGLE
The angle between the center line of the shaft and the center line of the ship is the horizontal angle and the angle between the center line of the shaft and either the base line or the designed waterline is the vertical angle.
SHAFT ALLEY
A watertight passage, housing the propeller shafting from the engine room to the bulkhead at which the stern tube commences. It provides access to the shafting and its bearings and also prevents any damage to the same from the cargo in the spaces through which it passes.
SHAFT COUPLING
The means of joining together two sections of a shaft, usually by means of bolts through flanges on the ends of the sections of the shafts.
SHAFT PIPE
See Stern Tube.
SHAFT STRUT
A term applied to a bracket supporting the outboard after end of the propeller shaft and the propeller in twin or multiple-screwed vessels having propeller shafts fitted off the center line. It usually consists of a hub or boss, fitted with a bushing, to form a bearing for the shaft, and two streamlined arms connecting it to the side of the ship. The inboard ends of the arms are fitted with palms for attachment to the shell or to interior framing.
SHAKES
Splits or checks in timbers which usually cause a separation of the wood between annular rings. A ring shake is an opening between annular rings; a through shake is an opening which extends between two faces of a timber.
SHAPE
A bar of constant cross section such as a channel, T-bar, angle bar, etc., either rolled or extruded.
SHAPING
Cutting, bending, and forming a structural member.
SHEARS
Large machines for cutting plates or shapes.
SHEAR LEGS
A rig for handling heavy weights, consisting of an A-frame of timber or steel with the top overhanging the base, having the lower ends fixed or pivoted and the top ends held either by fixed stays or by topping lifts which permit change of slope of the legs. Tackles are secured at the top of the frame through which the hoisting rope or cable is run. Sometimes called sheers.
SHEATHING
A term applied to the wood planking fitted over a steel deck, to the planking fitted over the underwater portion of a steel hull, and to the copper or alloy sheets with which the bottom of a wood ship, or a steel ship sheathed with wood, is covered.
SHEAVE
A wood or metal disk, having a groove around its cylindrical surface to permit a rope or chain to run over it without slipping off and a bushing for bearing on the pin or bolt on which it revolves.
SHEAVE HOLES
A term applied to apertures in masts, booms, and spars in which sheaves are installed.
SHEER
The longitudinal curve of a vessel's rails, decks, etc. the usual reference being to the ship's side; however, in the case of a deck having a camber, its center line may also have a sheer. The amount by which the height of the weather deck at the after or forward perpendicular exceeds that at its lowest point.
SHEER PLAN
A side elevation of the ship's form.
SHEER STRAKE
The topmost continuous strake of the shell plating, usually made thicker than the side plating below it.
SHELF
A wood ship term applied to the fore and aft timber that is fastened to the frames to form a support for the ends of the beams. See clamp.
SHELL EXPANSION
A plan showing the shapes, sizes, and weights of all plates comprising the shell plating, and details of the connections.
SHELL LANDINGS
Points marked on the frames to show where the edges of the shell plates are to be located.
SHELTER DECK
A term applied to a deck fitted from stem to stern on a relatively light superstructure.
SHIFT OF BUTTS
An arrangement of butts in longitudinal or transverse structural members whereby the butts of adjacent members are located a specified distance from one another, measured in the line of the members.
SHIM
(In naval architecture). A piece of wood or iron let into a slack place in a frame, plank, or plate to fill out a fair surface or line. Also applied to thin layers of metal or other material used to true up a bed plate or machine or inserted in bearings to permit adjustment after wear of the bearing.
SHIPSHAPE
A nautical term used to signify that the whole vessel, or the portion under discussion, is neat in appearance and in good order.
SHOAL
A small of timber or plank placed under the heel of a shore.
SHORES
Pieces of timber placed in a vertical or inclined position to support some part of a ship, or the ship itself, during construction or while in dry dock.
SHORE, SPUR or SIDE
A piece of timber placed in a nearly horizontal position with one end against the side of the ship and the other against the side of a dry dock or dock to keep the vessel at a desired distance from the face of the dock.
SHROUD
A principal member of the standing rigging, consisting of hemp or wire ropes which extend from or near a masthead to the vessel's side, or to the rim of a top, to afford lateral support for the mast.
SICK BAY
A name applied to the space on board a ship where members of the crew and passengers are given medical service and includes the dispensary, operating room, wards, etc.
SIDE PLATING
A term applied to the plating above the bilge in the main body of a vessel. Also to the sides of deck houses, or to the vertical sides of enclosed plated structures.
SIDING OF A FRAME
The fore and aft dimension of a frame.
SISTER HOOK
A hook made in halves and set on eyes facing each other in such a manner that it may be made to function as a link.
SKEG
The extreme after part of the keel of a vessel, the portion that supports the rudder post and stern post.
SKIN
The term usually applied to the outside planking or plating forming the watertight envelope over the framework. It is also applied to the inner bottom plating when it is called an inner skin.
SKYLIGHT
An erection built on a deck, having glass lights in its top and fitted over an opening in the deck for the purpose of admitting light and air to a compartment below.
SLACK
The opposite of taut; not fully extended as applied to a rope; to "slack away" means to pay out a rope or cable by carefully releasing the tension while still retaining control; to "slack off" means to ease up, or lessen the degree of tautness.
SLEEPERS
Timbers placed upon the ground or on top of piling to support the cribbing, keel, and bilge blocks.
SLEEVE
A casing, usually of brass, fitted over line or other shafting for protection against wear or corrosion, or as a bearing surface.
SLIDING WAYS
See launching.
SLING
A length of chain or rope employed in handling weights with a crane or davit. The rods, chains, or ropes attached near the bow and stern of a small boat into which the davit or crane tackle is hooked. The chain or rope supporting the yard at the masthead.
SLIP
The difference between the pitch of a propeller, or the mean circumference of a paddle wheel, and the advance of the ship through the water corresponding to one revolution. An inclined launching berth. A space between two piers for berthing a vessel.
SLIPWAY or BERTH
The space in a shipyard where a foundation for launching ways and keel blocks exists and which is occupied by a ship while under construction. The term berth is more properly applied to the space a ship occupies pier or at an anchorage.
SLUICE
An opening in the lower part of a bulkhead fitted with a sliding watertight gate, or small door, having an operating rod extending to the upper deck or decks. It is used to permit liquid in one compartment to flow into the adjoining compartment.
SLUSH
Grease, formerly obtained from the meat boiled in the coppers, used for lubrication and for slushing the spars after scraping them.
SMOKESTACK
A metal chimney or passage through which the smoke and gases are led from the uptakes to the open air.
SNUBBING
Drawing in the waterlines and diagonals of a vessel abruptly at their ends. The checking of a vessel's headway by means of an anchor and a short cable. The checking of a line or cable from running out by taking a turn about a cleat, bitts, or similar fitting.
SNY
To twist a plate into an uneven warped shape on a mold.
SOFT PATCH
A temporary plate put on over a break or hole and secured with tap bolts. It is made watertight with a gasket such as canvas saturated in red lead.
SOLE PLATE
A plate fitted to the top of a foundation to which the base of a machine is bolted. Also a small plate fitted at the end of a stanchion.
SOUNDING PIPE
A vertical pipe in an oil or water tank, used to guide a sounding device when measuring the depth of liquid in the tank. Also called a Sounding Tube.
SOUNDNESS OF STEEL CASTINGS
Absence in a casting of cavities or blow holes formed by air bubbles.
SPAN
The distance between any two similar members, as the span of the frames. The length of a member between its supports, as the span of a girder. A rope whose ends are both made fast some distance apart, the bight having attached to it a topping lift, tackle, etc. A line connecting two davit heads so that when one davit is turned the other follows.
SPANNER
A form of open-head wrench for use with special fittings whose character is such as to preclude the use of the ordinary type of wrench.
SPAR
A term applied to a pole serving as a mast, boom, gaff, yard, bowsprit, etc. Spars are made of both steel and wood.
SPECIFIC GRAVITY
The ratio of the weight of a given volume of any substance to the weight of an equal volume of distilled water. Since the distilled water weighs approximately 62.4 pounds per cubic foot, any substance, a cubic foot of which weighs less that this, has a specific gravity of less than one, and will float on water. Any substance of greater weight per cubic foot has a specific gravity of more than one and will sink. Specific gravity of gases is based in a like manner on the weight of air.
SPECTACLE FRAME
A single casting containing the bearings for and furnishing support for the ends of the propeller shafts in a twin screw vessel. The shell plating is worked outboard so as to enclose the shafts and is attached at the after end to the spectacle frame. Used in place of shaft struts.
SPIKE
A stout metal pin headed on one end and pointed at the other, made of either square or round bar, and used for securing heavy planks and timbers together.
SPILING
The curve of a plate or strake as it narrows to a point.
SPLICE
A method of uniting the ends of two ropes by first unlayering the strands, then interweaving them so as to form a continuous rope.
SPOT FACE
To finish off the surface around a bolt hole in a plane normal to the axis of the hole to provide a neat seat for the nut of washer.
SPRING
The deviation from a straight line or the amount of curvature of a sheer line, deck line, beam camber, etc., an elastic body or device which recovers its original shape when released after being distorted.
SPROCKET, SPROCKET WHEEL
A wheel on whose periphery are teeth or cogs designed to engage with the links of a pitch or sprocket chain through which motion is transmitted to a second sprocket.
SQUATTING
The increase in trim by the stern assumed by a vessel when running at high speed over that existing when she is at rest.
STABILITY
The tendency which a vessel has to return to the upright position after the removal of an external force which inclined her away from that position. To have stability, a vessel must be in a state of stable equilibrium.
STABILITY, RANGE OF
The number of degrees through which a vessel rolls or lists before losing stability.
STAGE
A floor or platform of planks supporting workmen during the construction or the cleaning and painting of a vessel, located either inside or outside the vessel.
STAGING
Upright supports, fastened together with horizontal and diagonal braces forming supports for planks which form a working platform or stage.
STAGGER
To zigzag rivet holes in adjacent rows.
STANCHIONS
Short columns or supports for decks, hand rails, etc. Stanchions are made of pipe, steel shapes, or rods, according to the location and purpose they serve.
STANDING RIGGING
Rigging that is permanently secured and that is not hauled upon, as shrouds, stays, etc.
STAPLING
Plates or angles fitted closely around or against continuous members passing through a watertight or oiltight member and caulked or welded to maintain the water or oil tightness of the structure.
STARBOARD
The right-hand side of the ship when looking from aft forward. Opposite to port.
STATEROOM
A private room or cabin for the accommodation of passengers or officers.
STAYS
The ropes, whether hemp or wire, that support the lower masts, topmasts, top-gallant masts, etc. in a fore and aft direction.
STEALER
A strake of shell plating that does not extend completely to the bow or stern.
STEERING GEAR
A term applied to the steering wheels, leads, steering engine, and fittings by which the rudder is turned.
STEM
The bow frame forming the apex of the intersection of the forward sides of a ship. It is rigidly connected at lower end to the keel.
STERN
The after end of a vessel; the farthest distant part from the bow.
STERN FRAME
A large casting or forging attached to the after end of the keel to form the ship's stern. Includes rudder post, propeller post, and aperture for the propeller in single-screw vessels.
STERN PIPES
A round or oval casting, or frame, inserted in the bulwark plating at the stern of the vessel through which the mooring hawser or warping lines are passed. Also called Stern Chock.
STERN POST
The main vertical post in the stern frame upon which the rudder is hung. Also called the Rudder Post.
STERN TUBE
The bearing supporting the propeller shaft where it emerges from the ship. It consists of a hollow cast-iron or steel cylinder fitted with brass bushings, which in turn are lined with lignum vitae, white metal, etc., bearing surfaces upon which the propeller shaft, enclosed in a sleeve, rotates.
STIFF, STIFFNESS
The tendency of a vessel to remain in the upright position, or a measure of the rapidity with which she returns to that position after having been inclined from it by an external force.
STIFFENER
An angle bar, T-bar, channel, etc., used to stiffen plating of a bulkhead, etc.
STOCKS
A general term applied to the keel blocks, bilge blocks, and timbers upon which a vessel is constructed.
STOP WATER
A term applied to canvas and red lead, or other suitable material, placed between the facing surfaces of plates and shapes to stop the passage of oil or water. Also applied to a wooden plug driven through a scarph joint between timbers to insure water tightness.
STRAIN
The measure of the alteration of form which a solid body undergoes when under the influence of a given stress.
STRAND
An element of a rope, consisting, in a fiber rope, of a number of rope yarns twisted together and, in a wire rope, of a primary assemblage of wires.
STRAKE
A term applied to a continuous row or range of plates. The strakes of shell plating are usually lettered, starting with A at the bottom row or garboard strake.
STRAKE, BILGE
A term applied to a strake of outside plating running in the way of the bilge.
STRAKE, BOTTOM
Any strake of plating on the bottom of a ship that lies between the keel and the bilge strakes.
STRENGTH MEMBER
Any plate or shape which contributes to the strength of the vessel. Some members may be strength members when considering longitudinal strength but not when considering transverse strength, and vice versa.
STRETCHERS
Athwartship, movable pieces against which the oarsmen brace their feet in pulling a small boat.
STRESS
The intensity of the force which tends to alter the form of a solid body; also the equal and opposite resistance offered by the body to a change of form.
STRINGER
A term applied to a fore-and-aft girder running along the side of a ship and also to the outboard strake of plating on any deck. The side pieces of a ladder or staircase into which the treads and risers are fastened.
STRINGER PLATES
A term applied to the outboard plates on any deck, or to the plates attached to the top flanges of a tier of beams at the side of a vessel.
STRUM BOX
The enlarged terminal on the suction end of a pipe which forms a strainer to prevent the entrance of material liable to choke the pipe. Also called Rose Box.
STRUT
A heavy arm or brace.
STUD
A bolt threaded on both ends, one end of which is screwed into a hole drilled and tapped in the work, and is used where a through bolt cannot be fitted.
STUDDING
The vertical timbers or framing of a wooden deck house, fitted between the sill and the plate.
STUFFING BOX
A fitting designed to permit the free passage or revolution of a rod or a pipe while controlling or preventing the passage by it of water, steam, etc.
SUBMARINE
Beneath the surface of the sea. A vessel which is capable of service both below and on the surface of the water.
SUNK FORECASTLE, SUNK POOP
A forecastle or poop deck which is raised only a partial deck height above the level of the upper or weather deck.
SUPERSTRUCTURE
A structure built above the uppermost complete deck; a pilot house, bridge, galley house, etc.
SWAGE
To bear or force down. An instrument having a groove on its under side for the purpose of giving shape to any piece subjected to it when the swage is struck by a hammer.
SWALLOW
A term applied to the oval or round opening in a chock or mooring ring. See Block.
SWASH BULKHEADS
Longitudinal or transverse nontight bulkheads fitted in a tank to decrease the swashing action of the liquid contents. Their function is greatest when the tanks are partially filled. Without them the unrestricted action of the liquid against the sides of the tank would be severe. A plate serving this purpose is called a swash plate.
SWIVEL
A special link constructed in two parts which revolve on each other, used to prevent fouling due to turns or twists in chain, etc.


--T--

TACKLE
Any combination of ropes and blocks that multiplies power. Also applied to a single whip which does not multiply power but simply changes direction.
TAFF RAIL
The rail around the top of the bulwark or rail stanchions of the after end of the weather deck, be it upper, main, raised, quarter, or poop.
TAIL SHAFT
The aft section of the shaft which receives the propeller.
TANKS
Compartments for liquids or gases. They may be formed by the ship's structure as double bottom tanks, peak tanks, deep tanks, etc., or may be independent of the ship's structure and installed on special supports.
TANK TOP
The plating laid on the bottom floors of a ship, which forms the top side of the tank sections or double bottom.
TARPAULIN
A term formerly applied to a paulin which was usually tarred.
TAUT
The condition of a rope, wire, or chain when under sufficient tension to cause it to assume a straight line, or to prevent sagging to any appreciable amount.
TEE BAR
A rolled or extruded structural shape having a cross section shaped like the letter T.
TELEGRAPH
An apparatus, either electrical or mechanical, for transmitting orders, as from a ship's bridge to the engine room, steering gear room, or elsewhere about the ship.
TELEMOTOR
A device for operating the valves of the steering engine from the pilot house by means of either fluid pressure or electricity.
TEMPLATE
A mold or pattern made to the exact size of a piece of work that is to be laid out or formed, and on which such information as the position of rivet holes, size of laps, etc., is indicated.
TENON
The end of a piece of wood cut into the form of a rectangular prism, designed to be set into a cavity or mortise of a like form in another piece.
TENSILE STRENGTH
The measure of a material's ability to withstand a tensile, or pulling stress without rupture, usually measured in pounds or tons per square inch of cross section.
TEST HEAD
The head or height of a column of water which will give a prescribed pressure on the vertical or horizontal sides of a compartment or tank in order to test its tightness or strength or both,
THOLES
The pins in the gunwale of a boat which are used for oarlocks.
THREAD
The spiral part of a screw.
THWARTS
Boards extending across a rowboat just below the gunwale to stiffen the boat and to provide seats.
TIE PLATE
A single fore-and-aft or diagonal course of plating attached to deck beams under a wood deck to give extra strength.
TILLER
An arm attached to the rudder head for operating the rudder.
TOE
The edge of a flange on a bar.
TOGGLE PIN
A pin having a shoulder and an eye worked on one end, called the head, and whose other end, called the point, has its extremity hinged in an unbalanced manner so that after being placed through a hole, it forms a T-shaped locking device to keep the pin from working out or being withdrawn without first bringing the hinged portion into line with the shaft of the pin.
TONGUE AND GROOVE
The term applied to a plank or board which has one edge cut away to form a projection, or tongue, and the opposite edge cut out to form a groove, the tongue of one plank fitting into the groove of the adjoining plank.
TONNAGE, GROSS
The entire internal cubic capacity of a vessel expressed in "tons" taken at 100 cubic feet each. The peculiarities of design and construction of the various types of vessels and their parts necessitate certain explanatory rulings in connection with this term.
TONNAGE, NET
The internal cubic capacity of a vessel which remains after the capacities of certain specified spaces have been conducted from the gross tonnage. Tonnage should not be confused with displacement.
TOP BREADTH
The width of vessel measured across the shelter deck.
TOPPING LIFT
A rope or chain extending from the head of a boom or gaff to a mast, or to the vessel's structure, for the purpose of supporting the weight of the boom or gaff and its loads, and permitting the gaff or boom to be raised or lowered.
TOPSIDE
That portion of the side of the hull which is above the designed waterline. On or above the weather deck.
TORQUE
The moment of a system of forces that causes rotation, as of a shaft or a rudder stock.
TRANSOM
A seat or couch built at the side of a stateroom or cabin, having lockers (transom lockers) or drawers underneath.
TRANSOM, TRANSOM BOARD
The board forming the stern of a square-ended row boat or small yacht.
TRANSOM FRAME
The last transverse frame of a ship's structure. The cant frames, usually normal to the round of the stern, connect to it.
TRANSVERSE
At right angles to the ship's fore-and-aft center line.
TRANSVERSE FRAMES
Vertical athwartship members forming the ribs.
TREADS
The steps or horizontal portions of a ladder or staircase upon which the foot is placed.
TREENAILS
Wooden pins employed instead of nails or spikes to secure the planking of a wooden vessel to the frames.
TRIM
The arithmetic sum of the drafts forward and aft above and below the mean water-line. The angle of trim is the angle between the plane of flotation and the mean water-line plane. A vessel "trims by the head" or "trims by the stern" when the vessel inclines forward or aft so that her plane of flotation is not coincident with her mean water-line plane. See Drag.
TRIPPING BRACKETS
Flat bars or plates placed at various points on deck girders, stiffeners, or beams as a reinforcement to prevent their free flanges from tipping.
TRUNK
A vertical or inclined shaft formed by bulkheads or casings, extending one or more deck heights, around openings in the decks, through which access can be obtained, cargo, stores, etc., handled, or ventilation provided without disturbing or interfering with the contents or arrangements of the adjoining spaces.
TUMBLE HOME
The decreasing of a vessel's beam above the waterline as it approaches the rail. Opposite of flare.
TURNBUCKLES
Used to pull objects together. A link into whose opposite ends two threaded bars, one left-handed, the other right-handed, are inserted.
TURRETS
Structures designed for the mounting and handling of the guns and accessories (usually main battery guns) of a war vessel. Turrets are constructed so as to revolve about a vertical axis usually be means of electrical or hydraulic machinery.


--U--

UMBRELLA
A metal shield in the form of a frustrum of a cone, secured to the outer casing of the smokestack over the air casing to keep out the weather.
UNSHIP
To remove anything from its accustomed or stowage place; to take apart.
UPPER DECK
Generally applied to the uppermost continuous weather deck.
UPPER WORKS
Superstructures or deck erections located on or above the weather deck. Sometimes applied to the entire structure above the waterline.
UPTAKE
A sheet-metal conduit connecting the boiler smoke boy with the base of the smokestack. It conveys the smoke and hot gases from the boiler to the stack and is usually made with double walls, with an air space between to prevent radiation of heat into adjacent spaces.


--V--

VALVE
A mechanical device used for controlling or shutting off the passage of a fluid or gas into or out of a container or through a pipe line.
VANE
A fly made of bunting and carried at the masthead or truck, which, being free to rotate on a spindle, indicates the direction of the wind.
VANG
Ropes secured to the outer end of a cargo boom, the lower ends being fastened to tackles secured to the deck, used for guiding and swinging and for holding the boom in a desired position. Also applied to ropes secured to the after end of a gaff and led to each side of the vessel to steady the gaff when the sail is not set.
VENTILATION
The process of providing fresh air to the various spaces and removing foul or heated air, gases, etc., from them. This may be accomplished by natural draft or by mechanical means.
VENTILATORS, BELL-MOUTHED or COWL
Terminals on open decks in the form of a 90-degree elbow with enlarged or bell-shaped openings, so formed as to obtain an increase of air supply when facing the wind and to increase the velocity of air down the ventilation pipe.
VISOR
A small inclined awning running around the pilot house over the windows or air ports to exclude the glare of the sun or to prevent rain or spray from coming in the openings when the glazed frames are dropped or opened. They may be of canvas or metal.
VOICE TUBE
A tube designed for the carriage of the human voice from one part of the ship to another. In its simplest form the voice-tube system includes a speaking connection between the pilot house and engine room only. In large war vessels the system becomes very complicated. Voice tubes are generally made up to about four inches in diameter and fitted with appropriate speaking and listening terminals. Telephones have largely replaced them.


--W--

WALES
The side planking on a wood ship lying between the bottom and the top-side planking.
WARP
A light hawser or tow rope; to move a vessel along by means of lines or warps secured to some fixed object.
WARDROOM
A room or space on shipboard set aside for use of the officers for social purposes and also used as their mess or dining room.
WASH PLATES
Plates fitted fore and aft between floors to check the rush of bilge water from side to side when the ship is rolling.
WATER LINE
A term used to describe a line drawn parallel to the molded base line and at a certain height above it, as the 10-foot water line. It represents a plane parallel to the surface of the water when the vessel is floating on an even keel, i.e., without trim. In the body plan and the sheer plan it is a straight line, but in the plan view of the lines it shows the contour of the hull line at the given distance above the base line. Used also to describe the line of intersection of the surface of the water with the hull of the ship at any draft and any condition of trim.
WATERSHED
A fitting on the outside of the shell of a ship over an air port, a door, or a window to prevent water which runs down the ship's side from entering the opening. One over an air port is also called a Brow or a Port Flange.
WATERTIGHT COMPARTMENT
A space or compartment within a ship having its top, bottom, and sides constructed in such a manner as to prevent the leakage of water into or from the space unless the compartment is ruptured.
WATERWAY
A narrow channel along the edge of the deck for the collection and disposal of water occurring on the deck.
WATERWAY BAR
An angle or flat bar attached to a deck stringer plate forming the inboard boundary of a waterway and serving as an abutment for the wood deck planking.
WAYS
See launching
WEATHER DECK
A term applied to the upper, awning, shade, or shelter deck, or to the uppermost continuous deck, exclusive of forecastle, bridge, or poop, that is exposed to the weather.
WEB
The vertical portion of a beam; the athwartship portion of a frame; the portion of a girder between the flanges.
WEB FRAME
A built-up frame to provide extra strength consisting of a web plate with flanges on its edges, placed several frame spaces apart, with the smaller, regular frames in between.
WEDGES
Wood or metal pieces shaped in the form of a sharp V, used for driving up or for separating work. They are used in launching to raise the vessel from the keel blocks and thus transfer the load to the cradle and the sliding ways.
WELDING
For all welding definitions see "General Specifications for Inspection of Material, Appendix VII, Welding, Part A, Section A-1, Welding Nomenclature and Definitions," issued by the Navy Department.
WHIP
A term loosely applied to any tackle used for hoisting light weights and serves to designate the use to which a tackle is put rather than to the method of reeving the tackle.
WILDCAT
A special type of drum whose faces are so formed as to fit the links of a chain of given size.
WINCH
A hoisting or pulling machine fitted with a horizontal single or double drum. A small drum is generally fitted on one or both ends of the shaft supporting the hoisting drum. These small drums are called gypsies, niggerheads, or winch heads. The hoisting drums either are fitted with a friction brake or are directly keyed to the shaft. The driving power is usually steam or electricity, but hand power is also used. A winch is used principally for the purpose of handling, hoisting, and lowering cargo from a dock or lighter to the hold of a ship and vice versa.
WINDLASS
An apparatus in which horizontal or vertical drums or gypsies and wildcats are operated by means of a steam engine or motor for the purpose of handling heavy anchor chains, hawsers, etc.
WIND SCOOP
A scoop-shaped fitting of sheet metal which is placed in an open air port with the open side forward for the purpose of catching air and forcing it into a cabin, stateroom, or compartment.
WING, WINGING
A term used to designate structural members, compartments, sails, and objects on a ship that are located a considerable distance off the fore-and-aft center line.
WORM, WORM SHAFT
A threaded shaft designed to engage the teeth of a wheel lying in the plane of the shaft axis. This type of gear is used for the transmission of heavy loads at low speeds.
WORMING
Filling the contlines of a rope with tarred small stuff preparatory to serving, to give the rope a smoother surface and to aid in excluding moisture from the interior of the rope.
WRENCH
A hand tool used to exert a twisting strain, such as setting up bolts, nuts, etc.
WRINKLING
Slight corrugations or ridges and furrows in a flat plate due to the action of compressive or shear forces.


--Y--

YARD
A term applied to a spar attached at its middle portion to a mast and running athwartship across a vessel as a support for a square sail, signal halyards, lights, etc.
YARDARM
A term applied to the outer end of a yard.
YIELD POINT
The stress at which a piece of material under strain yields markedly, becoming permanently distorted without increase of load.
YOKE
A frame or bar having its center portion bored and keyed or otherwise constructed for attachment to the rudder stock. Steering leads to the steering gear are connected to each end of the yoke for the purpose of turning the rudder. Yoke lanyards are lines extending from the ends of the yoke to the stern sheets of a small boat for use in steering.

25 August 2003