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Back-Board. A portable back support nicely designed and fitted on the after side of the stern thwart in a small motor or row boat.

Backbone. A term applied to the keel of a ship and sometimes to the center vertical keelson.

Backing. Making speed or having motion astern.

Back Hand Rope. See Rope, Back Hand.

Backstaff. This was an instrument used for deducing altitude when at sea, so named because it was employed with the observer’s back to the sun. It was also known as Davis’s Quadrant, the English quadrant, or, in France, Quartier l’anglois or Quartier de Davis.

Backstays. Stays which extend from all mast levels, except the lower, to the ship’s side some distance abaft the mast. They serve as additional supports to prevent the mast from going forward and at the same time contribute to the lateral support, thereby assisting the shrouds.

Baffle Plate, Boiler. See Boiler, Baffle Plate.

Baffle Plate, Condenser. See Condenser, Baffle Plate.

Balanced Rudder. See Rudder, Balanced.

Bale Measure. A term used where the capacity of a cargo hold is measured to the inside of the frames or cargo battens.

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

Ballast Port. See Port, Ballast.

Ballast Pump. See Pump, Ballast.

Ballast Tank. See Tank, Ballast.

Ballast, Water. Sea water confined to double bottom tanks, peak tanks or other designated compartments for use in obtaining satisfactory draft, trim or stability. In the days of the sailing vessel the object was attained by the use of solid ballast such as sand, gravel, rock, etc.

Ballasted Condition. A condition in which it becomes necessary to fill all or part of the ballast tanks in order to secure proper immersion, stability, and steering qualities. This condition may be the result of the consumption of fuel, stores, and water; or the absence of part or all of the designed amount of cargo.

Ball Joint. See Flexible Joint.

Balsa. A name used in South America to designate rafts made of light wood.

Baluster. Small upright pillar or column supporting the hand rail around a staircase.

Banjo Frame. A device for handling the propeller in an auxiliary screw steamer,

Bank. An elevation in the sea’s bottom which, if sufficient height, forms a shoal.

Bar, Boring. See Boring Bar.

Bar Furnace. See Furnace, Bar.

Bar Iron. Rolled bars having various forms of curvature.

Bar Keel See Keel, Bar.

Bar Stringer. See Stringer, Bar.

Barbettes. Cylindrical structures built up of armor plates extending from the protected deck of a war vessel to the lower side of the turret shelf plate. They form protective enclosures in which are located the turret stools, shell stowage flats and ammunition hoisting gear for the turrets.

Bare Poles. The condition of a sailing ship with no sails hoisted. "Not a rag set."

Barge. A craft of full body and heavy construction designed for the carriage of cargo but having no machinery for self propulsion.

Bark. A vessel having three masts, fore, main and mizzen. The two forward are square rigged and the after or mizzen is fore-and-aft rigged.

Barkentine. A vessel having three masts, fore, main and mizzen. The fore mast is square rigged and the main and mizzen fore-and-aft rigged.

Barnacles. A cirriped crustacean which adheres in clusters to the under water portion of vessels, piles, piers, etc.

Barometer. An instrument for measuring atmospheric pressure or weight to determine likely weather changes.

Bars, Boiler Grate. See Boiler Grate Bars.

Basin. A natural or artificial berthing place in which ships may safely float at any stage of the tide.

Basin Dry Dock. See Dry Dock, Graving.

Bath Brick. A calcareous or siliceous earth preparation compressed into bricks and used for cleaning bright-work; so named for having first been made near Bath.

Bathometer. An instrument, invented in 1875, to measure the sea’s depth.

Batten (noun). A thin strip of wood, usually tapered, used in laying down lines. A strip of wood or steel used in securing tarpaulins in place. (Verb) To secure by means of battens, as to "batten down a hatch."

Battening Down. Making the hatches watertight by means of tarpaulins firmly secured to the hatch coamings with battens, wedges, etc.

Battens, Cargo. A term applied to the planks that are fitted to the inside of the frames in a hold to keep the cargo away from the shell plating.

Battens, Hatch. See Hatch Battens.

Battens, Sheering. Long strips of wood which are clamped to the frames of a ship to locate the edges of the strakes of the shell plating in relation to the sheer of the ship’s deck.

Battle Cruiser. A naval vessel of the first class having great speed, carrying guns of the largest size and range and having good protection against gun fire and torpedo attack. She must be so designed as to be capable of keeping the sea in all weathers and have a maximum radius of action. Ships of this class are intended to sink an enemy and under some circumstances to lie in the main line of battle.

Battle Glass. Another name for a large sand glass that "ran" for 4 hours. Used on board ship during battles or in rough weather, when the violent movement of the vessel might adversely affect the mechanism of chronometers and other time-keeping and navigational equipment.

Battleship. A naval vessel of the first class carrying maximum armament and protection, both against gun fire and torpedo attack, and having good speed. She must be so designed as to be capable of keeping the sea in all weather and must have a large radius of action. Ships of this class are intended to lie in the regular line of battle and bear the brunt of the fighting.

Bead. A reinforcing ridge on a pipe or tube.

Beam. The extreme width of a ship. A transverse, horizontal member supporting a deck or flat.

Beam Angle Bar. An angle bar used in the construction of a deck beam or an angle bar composing a deck beam.

Beam, Awning, Anchor, Main, Lower, Shade, Shelter, etc. The deck beams are given the name of the deck that they support.

Beam Bracket. See Bracket, Beam.

Beam, Cant. A term applied to any of the beams supporting the deck plating or planking in the overhanging portion of the stern of a vessel. These beams radiate in fan shaped formation from the transom beam to the cant frames.

Beam Carlines. A term applied to beams either of timber or steel running fore and aft or diagonally between deck beams.

Beam Clamp. A device for attaching to the lower flange of a deck beam for hooking on a purchase, lead block, etc. It is made of metal in two parts, one of which has a sharp bend and hooks over the flange, the other, a straight flat piece, fits against the back of the web of the beam, the two parts being securely bolted together. In the lower end is a worked eye extending through both parts into which a ring is usually fitted.

Beam, Deck-Molding of. Its vertical dimension.

Beam, Deck-Siding of. Its horizontal dimension.

Beam, Hold. A term applied to any one of a tier of athwartship beams spanning the hold from frame to frame, and upon which no deck is fitted.

Beam, Intermediate. A term applied to a beam that is fitted in between, and running parallel to, the regularly spaced deck beams.

Beam Knees. A block of wood having a natural angular shape or a block cut to a bracket shape and used for connecting the deck beams to the frames in a wooden vessel. Also applied to the ends of steel deck beams that are split, having one portion turned down and a piece of plate fitted between the split portion, forming a bracket end.

Beam, Main. A term applied to the deck beam fitted at the point of maximum breadth of the vessel.

Beam Mold. See Mold, Beam.

Beam, Molded. The width over the widest portion of the ship measured to the outside of the frame angle or channel but inside the plating. Extreme: the greatest width outside the plating, armor or any part of the hull proper. Sometimes, but not always, taken over guards or fenders.

Beam, Panting. A term applied to an athwartship beam fitted in the bow or stern of a vessel, to panting stringers or to the under side of decks, for the purpose of preventing in and out motion of the sides of the vessel.

Beam, Transom. A strong deck beam situated in the after end of a vessel directly over the stern post, and connected at each end to the transom frame. The cant beams which support the deck plating in the overhang of the stern radiate from it.

Beams, Deck. A term applied to any of the main beams upon which the plating or planking of a deck is supported. These beams usually run athwartship from side to side of a vessel and are fastened to the frames. In the way of hatch openings they run from the side to the opening and are bracketed or clipped to the casing or coaming as the case may be. In fore and aft framing the beams run longitudinally and are bracketed to the bulkheads and also supported by heavy transverse web or belt beams.

Bear-a-hand. A command to give assistance at whatever is being done. Same as "Lend-a-hand."

Bearding. A term applied to the line of intersection of the plating and stem or stern post.

Bearers. A term applied to foundations and particularly to those having vertical web plates as their principal members. Also the vertical web plates of foundations are called bearers.

Bearing. The ship’s bearing is the direction of her course as indicated by the compass. The bearing of an object from the ship is the direction of the object expressed in points of the compass from the ship’s course, one point equaling 11°-15°.

Bearing Compass. This is a compass for the taking of bearings from sea-marks, which are sights on shore whose position is known in relation to the magnetic north. Consequently the ship’s position could be plotted on a chart. The bearing compass is also used at sea to measure the angle between a known star and the magnetic north, which enables a calculation to be made of the deviation of the steering compass. The first of these bearing compasses was no more than a square box containing an ordinary compass, with slits on opposite sides that had cross-hairs for sighting. In the 18th century two-armed sighting vanes with cross-hairs and a central pivot were added. The sun’s azimuth was measured from the shadow that fell on the compass card, thanks to lowering or raising the arm with the cross-hairs.

Bearing, Rudder. See Rudder Bearing.

Bearings, Roller. See Roller Bearings.

Beat to Windward. To work up against the wind by means of a series of tacks.

Becalmed. (Applied only to sailing vessels.) That condition in which there is insufficient wind to give steerage wary even though all sail is set.

Becket. A small grommet used for various purposes, as for reefing a sail with toggles; the extension of the cheek straps of a block together with the bolt and thimble or eye bolt to which is secured the standing part of the fall.

Bed Plate. A structure, consisting of a series of transverse girders connecting fore-and-aft members or girders. It is usually made of cast iron or steel, the girders having box or L-shaped sections. It may be either cast in one piece or built up of several castings bolted together. The bed plate is fitted for the support of the feet of the engine columns, as well as to provide for the support of the crank shaft bearings. Further, it assists in the distribution of the engine weight and stresses to the ship structure to which it is attached by holding down bolts.

Bees. Strips of wood or iron fastened to each side of the bowsprit.

Beetle. A heavy long-handled wood mallet with metal hoops, sometimes called a reaming beetle or hawing beetle, used by caulkers for striking a reaming or horsing iron.

Before. Toward the stem or in front of the vessel.

Beken of Cowes. This is the name of a firm of marine photographers of Cowes in the Isle of Wight, whose early photographs, and postcards made from them, have become collectors’ items. An entire series records the modern history of yachting and shipping generally. Alfred Beken and his son Frank moved in 1888 from Canterbury to Cowes, where the father bought a chemist’s shop, and eventually received a Royal Warrant for supplying medicines and scents to Queen Victoria. Alfred was a keen photographer, and indulged his hobby by taking pictures of local scenes and happenings. Frank, also a keen photographer from an early age, developed the craft as a business. In due course he was commissioned by wealthy yacht-owners and even by royalty to take pictures of themselves and their vessels.

Belay. To secure a rope or line about a cleat or belaying pin by winding it back and forth in the manner of the figure eight.

Belaying Pin. A small iron or tough wood pin consisting of a head, shoulder and shank. The pin, being securely fitted in a rail, is used for belaying the hauling parts of light running gear, signal halyards, etc.

Bell Crank. A bent lever used to alter the direction of application of a force.

Bell Mouth. A term applied to an expanded, trumpet-shaped fitting, used on the ends of voice tubes, etc.

Bell, Ship’s. A bell and clapper of the usual shape used aboard ship as a means of denoting the time at regular intervals by day and by night; viz., 12 o’clock, midday or midnight, 8 bells; 12.30, 1 bell; 1 o’clock, 2 bells; 1.30, 3 bells; 2 o’clock, 4 bells; 2.30, 5 bells; 3 o’clock, 6 bells; 3.30, 7 bells; 4 o’clock, 8 bells; 4.30, 1 bell; 5 o’clock, 2 bells; 5.30, 3 bells; 6 o’clock, 4 bells; 6.30, 5 bells; 7 o’clock, 6 bells; 7.30, 7 bells; 8 o’clock, 8 bells; 8.30, 1 bell; 9 o’clock, 2 bells; 9.30 3 bells; 10 o’clock, 4 bells; 10.30, 5 bells; 11 o’clock, 6 bells; 11.30, 7 bells. Ship’s bells are also used as a signal when anchored in a fog and as an alarm in emergencies.

Below. Underneath the surface of the water. Underneath a deck or decks.

Bend. The act of securing one thing to another; as, an anchor to a cable; a sail to a yard, one line to another, or to a buoy, boat, etc.

Bend. A term applied to a pipe that is bent through an angle of from 45° to 180°.

Bend, Return. A U-shaped pipe fitting for the purpose of connecting the ends of two parallel pipes, thus providing for a return flow.

Bending Moment. Any beam, girder or structure subject to bending is acted upon by a "bending moment." The bending moment at any point in the structure is the sum of the products of the force acting to produce bending and the perpendicular distances from the lines of action of the forces to the point under consideration.

Bending Shackle. The heavy shackle which connects the chain cable to the ring or shackle attached to the shank of an anchor,

Bending Slab or Block. A cast iron slab usually about five feet square, perforated with holes 2" square arranged in a manner similar to a checker board. The slab is generally about 2" thick except around the edges where it is about 8" deep. The floor in front of the furnace in the plate and angle shop is made up of a number of these slabs raised to the level of the furnace door. Such work as furnacing plates and bending and beveling is done on these slabs, the holes being used for setting pins around which to bend frames and providing a means for dogging down the work and any forms used.

Berth. A term applied to a bed or a place to sleep. Berths, as a rule, are permanently built into the structure of the staterooms or compartments. They are constructed singly and also in tiers of two or three, one above the other. When single, drawers for stowing clothing are often built-in underneath. Tiers of berths constructed of pipe are commonly installed in the crew space. The term berth is also used to designate a stateroom or cabin, and also to specify a position; for example, he has the berth of captain. Still another use of the term is to designate the place where a ship is docked or tied up.

Bessemer Steel. See Steel and Iron.

Between Decks. The space between any two, not necessarily adjacent, decks. Frequently expressed as "’Tween decks."

Betwixt Wind and Water. At or near the water line at which a ship is floating.

Bevel Board. See Board, Bevel.

Bevel, Closed. A term applied where one flange of a bar is bent into an acute angle with the other flange.

Bevel Gear. A gear designed to transmit power from one shaft to another with which it makes a definite angle. When the shafts are at right angles to each other, the gears are called miters.

Bevel Lines. See Lines, Bevel.

Bevel, Open. A term applied where one flange of a bar is bent out to an obtuse angle with the other flange. In the bow and stern the frames are given an open bevel so that the inner flange will connect to the transverse beams without making it difficult to rivet the outer flange to the shell.

Bevel-Faced Hammer. A hammer used in riveting having its face set at an angle.

Bevel-Faced Holding on Hammer. A large hammer with its face sloped. It is held against the head of a rivet while it is being driven.

Beveling Machine. A machine used for beveling steel angles and other shapes. A set of steel discs is operated by an electric motor and set to any desired angle by a mechanism attached to a threaded shaft operated at one end by a hand wheel. The bars are heated in a bar furnace and run through the beveling machine while hot.

Bibb. The bent outlet of a cock.

Bight (of a rope). A loop or bend in a rope, though, strictly considered, any part between the two ends may be termed the bight.

Bilge. (Noun) The rounded portion of a vessel’s shell which connects the bottom with the sides. (Verb) To open a vessel’s lower body to the sea.

Bilge and Ballast System. A system of piping generally located in the hold of a vessel and connected to pumps. This system is used for pumping overboard accumulations of water in holds and compartments, and also for filling ballast and peak tanks.

Bilge Discharge Pipe. A pipe on the discharge side of a bilge pump for discharging water pumped from the bilges or bottom of the vessel overboard.

Bilge Ejector. An apparatus designed for the expulsion of the water accumulated in a vessel’s bilges.

Bilge Injection. The suction from the bilges to the main circulating pumps which permits discharging bilge water overboard or through the condensers in case of a leak of sea water into the bilge.

Bilge Injection Water. The water pumped from the bilges by the main circulating pumps.

Bilge Inlet. The suction side of a bilge pump or circulating pump which can be used for pumping water from the bilges.

Bilge Keel. See Keel, Bilge.

Bilge Keelson. See Keelson, Bilge.

Bilge Pump. See Pump, Bilge.

Bilge Strake. See Strake, Bilge.

Bilge Stringer. See Stringer, Bilge.

Bilge Suction Pipe. See Pipe, Bilge Suction.

Bilge Water. Drainage water which accumulates either in the bottom or bilge.

Bilge and Fire Pump. See Pump, Fire and Bilge.

Bilge ways. The timbers or part of the launching ways directly under the bilge of a ship.

Bill-board. The inclined anchor bed fitted at the intersection of the forward weather deck and shell. On some ships a tripping device is fitted on the bill-board so that by turning a rod the anchor will slide off into the water.

Bind. To secure the end of a rope against unlaying by taking turns of twine or small-stuff around it. The term is synonymous with whip.

Binnacle. A stand or case for housing a compass so that it may be conveniently consulted. Binnacles differ in shape and size, according to where used and the size of compass to be accommodated. A binnacle for a ship’s navigating compass consists essentially of a pedestal at whose upper end is a bowl shaped receptacle having a sliding hood-like cover. This receptacle accommodates the gimbals supporting the compass. Compensating binnacles are provided with brackets or arms on either side, starboard and port, for supporting and securing the iron cylinders or spheres used to counteract the quadrant error due to the earth’s magnetization of the vessel. This type of binnacle is usually placed immediately in front of the steering wheel, having its vertical axis in the vertical plane of the fore-and-aft center-line of the vessel.

Binnacle Clock. A clock made for use aboard ship, to show the nautical watches, and to strike from one to eight.

Binoculars, Marine. A form of telescope designed for the use of both eyes at the same time.

Bitter-end. The extreme inboard end of a chain cable which is secured in the chain locker.

Bitts. A term applied to short metal or wood columns extending up from a base plate attached to a deck or bulwark rail, timbers produced through and a short distance above a deck, or columns fitted to a windlass for the purpose of securing and belaying ropes, hawsers, cables, etc. Also called bollards.

Bitts, Mooring. A term applied to the bitts to which the mooring lines are attached.

Bitts, Towing. A term applied to the bitts fitted on the deck of a vessel for the purpose of belaying or fastening the towing hawsers.

Bitumastic. A black tar-like composition largely of bitumen or asphalt and containing such other ingredients as rosin, Portland cement, slaked lime, petroleum etc. It is sold under various trade names in the form of a solution, an enamel, and a cement, the exact composition being kept more or less a secret by the manufacturers. All three forms adhere well to steel when properly applied and are practically impervious to water. The solution is applied cold with a brush and is used as a priming coat for either the enamel or cement. The enamel is applied hot, after the solution is nearly dry or set, by being poured, where practicable, or otherwise spread over the surface, forming a fairly elastic surface after hardening and cooling. The cement is also applied hot, but being more difficult to apply than the enamel is used generally only on horizontal surfaces. The solution and enamel or cement is used as a protective coating in ballast and trimming tanks, chain lockers, reserve feed and fresh water tanks, coal bunkers, engine and boiler foundations, shaft alleys and below floor plates in vessels and as a damp-proof coating on the walls of cold storage spaces.

Bituminous Solution. See Paint.

Black Balls. A vessel which from any accident is not under command shall carry by day in a vertical line, one over the other, not less than six feet apart, where they can best be seen two black balls or shapes, each two feet in diameter. A vessel employed in laying or picking up telegraph cable shall carry in the daytime, in a vertical line, one over the other, not less than six feet apart, where they can best be seen, three shapes, not less than two feet in diameter, of which the highest and lowest shall be globular in shape and red in color and the middle one diamond in shape and white in color. These balls are to be taken by other vessels as signals that the vessel showing them is not under command and cannot therefore get out of the way. They are not signals of distress. A steam vessel proceeding under sail only, but having her funnel up, shall carry, in daytime, forward, where it can be seen, one black ball or shape, two feet in diameter

Blacksmiths. Workmen engaged in heavy forging, pressing, stamping, case hardening, annealing, tempering, tool dressing, etc.

Blade Friction. See Turbine, Blade Friction.

Blades, Turbine. See Turbine Blades.

Bleeder. A term applied to a cock fitted to a pipe line for the purpose of drawing off condensation.

Bleeders. A term applied to plugs screwed into the bottom of a ship to provide for drainage of the compartments when the vessel is in dry dock.

Blind Pulley. A circular block of hard wood with rounded edges perforated by several holes having grooves running from them to one side of the block. One of these blocks is secured to an end of a part of the standing rigging, as a shroud, and another to some part of the ship, they are then connected to one another by a lashing passing through the holes. These wooden blocks are commonly called dead eyes.

Blinker Signals. An electrical appliance used for signaling by the Morse code, consisting of two lanterns and two controllers. The lanterns are secured at the ends of the signal yard, while one controller is located on either side of the bridge.

Block. A device used in applying power to move heavy weights by means of tension in a cable. It consists of a frame made of wood or metal containing one or more pulleys or sheaves, set side by side and turning on the same axis. If more than one sheave is fitted, the sheaves are separated by divisions of the same outline as the sides or cheeks of the block. In referring to blocks the words single, double or triple are prefixed to tell the number of sheaves they carry in their frames. The position a block occupies in the tackle of which it is a part determines what its fitting should be, that is, whether or not it should have affixed eyes, hooks or beckets. The block on the stationary end of the tackle has on its end a hook or an eye by which it is fastened. The Becket is a fitting on one end of a block to which is secured one end of the tackle rope or "fall," and may be either on the stationary or movable block. Blocks derive their names from the purposes for which they are used, the places which they occupy or from distinctive features of their form or construction

Block and Block; Two Blocks; Chock-a-block. The name given the condition of a tackle when the two blocks have been drawn together so that no more power can be derived from them.

Block, Cheek. A block made with one of the sides or cheeks formed so that it can be secured to a spar.

Block, Clump. A short, thick, single block with a large swallow.

Block Coefficient. See Coefficient, Block.

Block, Fiddle. A block with two sheaves of different diameters, placed one above the other.

Block Fittings. Swivel, loose, stiff, side or sister hooks, regular or upset shackles, swivel jaws or eyes, stiff eyes, links, etc., mounted on various blocks to adapt the block for purposes required.

Block, Jewel. The block fastened to a yard to take the studding sail halyards.

Block, Snatch. A single block with a hook having one end of the frame arranged so that it can be hinged up to allow the bight of a rope to be placed on the one end of the rope through the swallow. Snatch blocks are used to lead ropes around obstructions which prevent straight leads to a winch or capstan.

Block Stopper. A short piece of rope attached to a stationary block and used to temporarily secure the running part of a fall.

Block, Swivel. A block having a swivel attachment to its supporting hook or shackle, thus allowing it to revolve.

Blocks, Bilge. Short heavy pieces of timber similar to the keel blocks. They are placed at intervals on both sides of the keel as supports for the bottom of a ship both when building and in dry dock.

Blocks, Gin. Sometimes called Gins. Single blocks with a metal frame having a sheave of large diameter for ease in overhauling and used where the operation of hoisting by a single part is to be performed many times in succession as in hoisting cargo.

Blocks, Keel. Short heavy timbers about twelve inches square in section, placed one above the other, up to a height of about five or six feet, and used to support the keel of a vessel when building and when in dry dock. They are placed under the keel from bow to stern and re-spaced a sufficient distance apart to allow access to the work.

Blocks, Secret. Single blocks with the sheave completely enclosed by the frame. Two holes are left on one end for the rope to pass in, around the sheave and out again. They are used to prevent the fouling of any rigging with which they come in contact.

Blocks, Sister. Two single blocks joined together at their ends by a swivel.

Blow, Bottom. See Boiler Blow, Bottom.

Blow, Surface. See Boiler Blow, Surface.

Blower. Common name for a speaking tube for communicating with various essential parts of the ship. Each speaking tube had its own nameplate, indicating to whom it communicated. The ends were formed into mouth-pieces, in which whistles were fitted. Actually "voice pipes", as they called them originally, were used in the Royal Navy long before engines and engine-rooms.

Blowers. Mechanical devices used for artificial air supply to machinery or other enclosed spaces and forced draft. The centrifugal type is in almost universal use at the present time. It consists of a series of vanes mounted on radial arms supported on a central revolving shaft. Air is taken in at the center and is charged by centrifugal force from the blade tips. Blowers are driven by reciprocating or turbine steam engines or electric motors. In the location of the Blower and the design of supply leads, great care must be taken as to economical use of space and the securing of a satisfactory point of intake.

Blow-off Valve, Blow-through Valve. See Valve, Blow-off.

Blue Peter. A blue flag having a white square in its center hoisted as a signal that the ship is ready to begin her voyage.

Board, Bevel. A wooden board upon which is drawn the bevels applying to some part of the ship’s structure such as the frames, and given to the workmen in the yard for ready reference where a paper plan or sketch would not stand rough usage.

Boarding. The act of going on board a ship.

Boat Deck. See Deck, Boat.

Boat Deck Stringer. See Stringer, Boat Deck.

Boat Deck Stringer Bar. See Stringer Bar.

Boat Hook. A metal fitting in the form to one or more hooks and a prong, attached to the end of a pole. They are used for catching, holding and steadying small boats.

Boat Stowage. The provisions made aboard a ship for stowing and launching life boats.

Boat Tanks. Air tight compartments in ship’s small boats to provide buoyancy when a boat is filled with water.

Boatswain (Bo’s’n). One of the lower officers on shipboard who has immediate charge of the deck force, deck gear, boats, rigging, cordage, etc.

Boatswain’s Call. A small silver whistle or pipe used by a boatswain or his mates to summon men to their stations and direct them in their duties.

Boatswain’s Chair. A piece of plank forming a seat hung in two straps on which a man may be hoisted aloft or lowered over the ship’s side.

Bobstay Piece. A term applied to the forward projecting edge timber of the stem directly below the bowsprit.

Bobstays. The chains or ropes attached underneath the outer end of a bowsprit and led to the stem to prevent the bowsprit from jumping. Frequently two or three bobstays are fitted; when three, they are designated as inner, middle, and cap bobstays; when two, as inner and cap bobstays.

Body, After. That portion of a ship’s body aft of the midship section.

Body Plan. A plan consisting of a pair of half transverse elevations or end views of a ship, both having a common vertical middle line, so that the right hand side represents the ship as seen from ahead, and the left hand side as seen from astern. On the body plan appear the forms of the various cross sections, the curvature of the rail and deck lines at the side, and the projections as straight lines of the waterlines, bow and buttock lines, and the diagonal lines.

Body-post. See Propeller Post, Stern Post.

Boiler. Any vessel, container or receptacle that is capable of generating steam by the internal or external application of heat. There are two general classes of boilers, i. e., fire tube and water tube.

Boiler Acidity. A term used when the feed water is acid.

Boiler, Air Required. The amount of air that should be supplied to a furnace may be calculated from a flue gas analysis and the weight of carbon remaining in the ashes.

Boiler Alkalinity. A term used when the feed water is alkaline and has the power of neutralizing acids.

Boiler, Analysis of Flue Gas. A determination of the quality of the gases passing up the stack for the purpose of ascertaining how complete the combustion of the fuel is.

Boiler Ash Pit. The space underneath the grate bars in a furnace which has the double function of receiving ashes and providing air space for combustion of the fuel.

Boiler Baffle Plate. A plate perforated with small holes and used in the top drums of water tube boilers to separate the steam from the water. Plates in fire tube boilers to induce the circulation of water in the proper direction are also called baffle plates.

Boiler Bearers. See Boiler Foundation.

Boiler Blow, Bottom. A valve located near the bottom of the boiler for the purpose of blowing off the mud, sediment or dense water. Also sometimes used for emptying a boiler when examination and cleaning are required. The better practice for emptying, however, is to let the boiler cool down and either draw or pump the water out.

Boiler Blow, Surface. A valve with pipe connections to the interior of the boiler and overboard, used for the purpose of blowing off the scum and grease that collect on the surface of the water.

Boiler Bracing. The stay rods, stay bolts and stay tubes used in supporting the flat surfaces in a boiler. A cylindrical surface requires no bracing for internal pressure, but ring stiffeners, ribs or corrugations are necessary for external pressure,

Boiler Bracket. A bracket connected to both the boiler and ship structure.

Boiler Capacity. The highest number of boiler horsepower that can be generated in a boiler. The rated horsepower is commonly based on 10 square feet of heating surface per horsepower.

Boiler Chocks. Brackets to prevent fore and aft motion of the boiler.

Boiler Circulation. The continuous circulation of water established in a boiler, with a view to increasing its efficiency, durability and safety. Proper circulation adds to the ability of the water to take up heat, reduces the tendency toward violent boiling which causes excessive priming, and prevents in a large measure the formation of deposits on the heating surfaces. It also adds to the durability and safety of the boiler by keeping all parts at a nearly uniform temperature, thereby reducing the liability of unequal strains due to expansion and contraction.

Boiler Combustion Chamber. A chamber or space adjacent to the furnace in a boiler designed for the purpose of completing the combustion of the gases from the fuel.

Boiler Compounds. Substances, generally having a soda or tannic content, that are injected into the boiler with the feed water or through a soda cock. These compounds should be used to prevent scaling, rather than to break it up after it has already occurred. Care should be taken to suit the compound to the water used rather than to use the compound as a cure all.

Boiler Corrosion. Destruction of the steel parts due to the oxidizing properties of the feed water. It may result from galvanic action, the presence of air or acidity of the water.

Boiler Crown Sheet. The plate over the furnace in a Locomotive type, or the plate over the combustibility chamber in a Scotch type of boiler.

Boiler, Donkey. A small boiler placed aboard ship for operating auxiliary and deck machinery, heating plant, etc., when the fires are drawn from the main boilers.

Boiler Door, Ash Pit. A single plate door fitted over the ash pit and serving as a damper.

Boiler Door Frame. See Boiler Furnace Front.

Boiler Door, Furnace. A door consisting of a steel plate with a cast iron inner plate perforated with small holes and so fitted that there is an air space between the two plates. In addition to the hinges and opening bar the door usually has a peephole which is large enough to allow a bar to be used for stirring up the fire.

Boiler Drum. A rectangular or cylindrical container into which headers are connected or nests of pipes expanded. They provide space for steam, and in most cases for sufficient water to prevent foaming when steam is separating from the water.

Boiler Drum Head. A circular plate flanged for connection to the sides of the drum and pressed to a convex shape. It is used to close the end of the drum.

Boiler Dry Pipe. A pipe running along the top of the steam space in which slots are cut in the top or sides for the purpose of admitting only dry steam to the line. One end of the pipe has a blank ending and the other end is connected to the steam outlet. Drainage holes are drilled along the bottom of the pipe.

Boiler Economizers. See Boiler Feed Water Heater.

Boiler Efficiency. This depends principally on having sufficient area and proper arrangement of the grate and heating surfaces combined with sufficient combustion space to insure complete combustion of the gases before they enter the stack. Good draft and circulation of water, and clean heating surfaces are also important items that are necessary to obtain the greatest efficiency.

Boiler Electrolysis. See Boiler, Galvanic Action.

Boiler Evaporation. A measure of the amount of water evaporated per pound of coal or per square foot of heating surface per hour.

Boiler Feed Check Valve. See Valve, Check, Boiler Feed.

Boiler Feed Pipe, Internal. A pipe with a blank end and perforated with numerous small holes through which feed water is delivered to the boiler.

Boiler Feed Water. The feed water should be as free from the carbonates and sulphates of lime and magnesia as possible. Hard or salt water should never be used except in an emergency. Due to the fact that water loses its solubility at high temperatures these substances are deposited in the form of scale upon the heating surfaces.

Boiler Feed Water Heater. A container used for heating the feed water before it is injected or pumped into the boiler. The feed water may be heated by passing it through tubes around which the exhaust steam, or in some cases live steam, circulates, or by allowing the water to circulate around tubes through which exhaust or live steam passes. Other types which are frequently called economizers utilize the heat from the waste flue gases. The advantages of a feed water heater are as follows, viz.: They utilize heat that would otherwise be wasted. They increase the steam capacity by shortening the time necessary to bring the water up to steaming temperature. They also prevent strains in the boiler due to the introduction of cold water, and they retain a large portion of the scale that would otherwise be deposited in the boiler.

Boiler, Fire Tube. If the hot gases from the furnace or combustion chamber are led to the uptake through tubes around which water circulates the boiler is of the fire tube type. Fire tube boilers have the advantage over the water tube boilers in the following points, viz.: Less damage is done when it becomes necessary to use salt water. Not so much attention need be given to the regulation of the supply of feed water. Less trouble with the tubular elements. Better adapted for handling by firemen who are transient or below the average in intelligence. Not so sensitive.

Boiler Firing. No general rule for firing can be given. as the desirable thickness of the fire and methods used depend on the quality to the fuel, draft and numerous other conditions. With bituminous coal there are two common methods, called spreading and coking. In the spreading method the coal is thrown evenly in a thin layer over one furnace at a time. This method requires frequent firing. In the coking method the coal is thrown in the forward end of the furnace, allowed to coke and then spread out over the entire furnace. The ashes are sometimes removed by pulling the good coal from the back of the furnace, then dumping the ashes in the back end. The good coal in the forward end is then pushed back and the ashes in the forward end dumped. Steam jets may be used in the ash pit to soften the clinkers.

Boiler Flue. A large tube used to convey hot gases through a boiler.

Boiler Flue Gas. The gases passing up the stack.

Boiler, Flue Type. In this type the furnace is below one end of the boiler. The flames and hot gases pass along the sides and underneath the shell and return through flues inside the boiler to the uptake.

Boiler, Flue and Return Tube Type. This type has a rectangular shaped furnace located in the front. The flames and hot gases pass through a flue or flues to a combustion chamber in the back and return through small tubes to the uptake which is located at the front end.

Boiler Foaming. When there is a scum or suspension of particles on the surface of the water in a boiler, the steam has difficulty in freeing itself and foaming occurs. This condition may be due to the presence of organic matter or excess of boiler compounds used for treating the water.

Boiler Forced Draft. An artificial means for increasing the rate of combustion in a boiler by creating an excess of pressure under the fuel or a suction above it and at the same time provide for the proper supply of air to the grates as required by the rate of combustion desired. Blowers and fans are used to accomplish these results.

Boiler Foundation. The structure upon which the boiler is secured. It generally consists of girders built up from plates and shapes and securely fastened to the boiler and riveted to the ship structure. With a cylindrical boiler the athwartship girders are often called saddles.

Boiler Front. The front head of a fire tube boiler. Water tube boilers generally have an ornamental front which is fitted to the forward supporting frame. Large doors for access to the front headers and the frames for fire and ashpit doors are fitted to it.

Boiler Fuel. The most commonly used fuels are anthracite and bituminous coal, although peat, lignite, wood and many kinds of refuse are used. The liquid fuels are generally crude oil or petroleum.

Boiler Fuel Consumption. The rate of fuel burned expressed in ounces per square foot of grate surface, heating surface, or I.H. P. per hour.

Boiler Funnel. See Smoke Stack.

Boiler Furnace Front. A steel plate attached to the front of the furnace which serves as a door frame and as a support for a cast iron protection plate on the fire side. The cast iron plate is perforated with a large number of small holes to prevent it from burning, and has an air space between it and the front plate.

Boiler Gage, Steam. An instrument which indicates the deference between the steam pressure in a boiler and the pressure of the atmosphere.

Boiler Gage, Water. A gage containing a glass tube, about 12" to 15" long, in which the water level in the boiler is indicated. Metal fittings, containing stop valves, ball non-return valves, or a combination of both, are attached to the ends of the glass tube, and these in turn are attached to small metal pipes, the upper one of which should be connected to the steam space of the boiler near the top and the lower one to the water space near the bottom. A drain cock is also provided at the bottom for blowing out the glass. On large boilers the gage glass is attached to a large pipe which is direct connected to the steam and water spaces. This prevents fluctuations in the water level in the glass. The glass tubes used in water gages are usually about 5/8 to 3/4 inches in diameter and about 1/8 inch thick. They are frequently broken, and, therefore, as an added precaution, tell-tale or gage cocks are provided. Where the glass is connected to the water and steam spaces direct, these cocks are attached to the boiler, but in large boilers where the glass is attached to a pipe column, the tell-tale cocks are attached to this pipe covering the range of the glass reading.

Boiler Galvanic Action. To prevent galvanic action in a boiler, zinc plates are installed. They should have as good metallic connection with the steel as possible. In addition to preventing electrolysis, they take up oxygen more readily than steel, thus preventing corrosion.

Boiler Girder. A plate girder usually consisting of two plates about 5/8" to 3/4" thick, connected together by rivets passing through thimbles or short pieces of pipe and used to support the top of the combustion chamber in a fire tube boiler. The stay bolts forming the connection between the girder and the crown sheet pass between the plates making up the girder and are fitted with nuts and retaining washers at the top.

Boiler Grate Surface. The area of the grate.

Boiler, Gunboat Type. This boiler is somewhat similar to the Scotch boiler, having a furnace and combustion chamber, but instead of the hot gases returning to the front end they continue through tubes to the rear end of the boiler where the uptake is situated. This gives a smaller diameter but longer boiler and is suitable where low head room is desired.

Boiler, Hand-Hole. A small elliptical hole in a boiler fitted with a cover on the inside which is held in place by a clamp or strong back on the outside. The purpose of hand holes is to provide access for cleaning.

Boiler Hatch. See Hatch, Boiler.

Boiler Heads. Plates used to close the ends of the boiler shell in fire tube boilers. They are usually flanged around the edge for connection to the shell.

Boiler Heating Surface. The area of the surfaces of the boiler that is subject to the heating action of the flames and hot gases. In fire tube boilers there should be from 2 to 5 square feet of heating surface for each I. H. P. required.

Boiler, High Pressure. A boiler designed for working pressures greater than 150 lbs.

Boiler Horsepower. One boiler horsepower is conventionally taken as being equal to an evaporation of 345 lbs. of water per hour from and at 212° Fahrenheit. As the efficiency of a boiler depends on many things, it follows that the accuracy of its capacity can only be determined by a boiler test.

Boiler Incrustation. See Scale.

Boiler Lagging. See Insulation.

Boiler, Leg Type. See Boiler Flue and Return Tube.

Boiler, Locomotive Type. In this type there is a rectangular furnace in the front with fire tubes leading to the back end and uptake. In way of the firebox the sides are flat and the top flat or rounded. The remainder of the boiler is cylindrical.

Boiler, Low-Pressure. A boiler designed for working pressures of 50 lbs. or less.

Boilermakers. Workmen engaged in the construction and erection of the component parts of boilers, condensers, and uptakes.

Boiler Manhole. A hole in a boiler or drum large enough to allow a man to center for the purpose of examining and cleaning out the interior. Specially designed covers are made for manholes with bolt and dog fastenings.

Boiler Manhole Ring. A reinforced ring of metal fitted around the manhole to provide local stiffness.

Boiler, Medium-Pressure. A boiler designed for working pressures from 50 to 150 lbs.

Boiler Mud Drum. Either a cylindrical or rectangular container, located at the bottom of the boiler as remote as possible from the fire, for the purpose of catching impurities deposited from the water. It is provided with access holes for cleaning out.

Boiler Pitting. Corrosion of isolated spots in a boiler.

Boiler Priming. The amount of moisture suspended in the steam generated.

Boiler Room. Used to designate a compartment in a ship or building in which one or more boilers are installed.

Boiler Room Bulkhead. See Bulkhead, Boiler Room.

Boiler Room Casing. See Casing, Boiler Room.

Boiler Saddle. See Boiler Foundation.

Boiler, Safety Valve. See Valve, Safety.

Boiler, Scotch. This type consists of a cylindrical shell with internal circular furnaces which are generally corrugated to enable them to withstand external pressure. Grate bars subdivide the furnaces into two parts, the upper part for the fire and gases and the lower part for the ash pit. The hot gases pass to a combustion chamber in the back of the boiler and from there return through tubes to the front end and uptake. The water should be kept to a level above the top of the tubes and combustion chamber and occupies all the space not taken up by the furnaces, combustion chamber, tubes, stay rods, stay bolts and steam space. Large Scotch boilers have as many as four furnaces.

Boiler Seating. See Boiler Foundation.

Boiler Shell. The outside plating of the boiler with the exception of the end plates.

Boiler Space. A term applied to the compartment or compartments in which the boilers are installed.

Boiler Stack. See Smoke Stack.

Boiler Stays. Steel rods or tubes used to brace flat plate surfaces in fire tube boilers.

Boiler Stop Valve. See Valve, Stop, Boiler.

Boiler, Sub-Division. A term applied to the manner in which the interior of a boiler is subdivided by partitions for the purpose of separating the fire and hot gases from the water. The circulation of the water and the heating efficiency depend largely on the manner in which this is done.

Boiler Throat Sheet. A plate connecting the cylindrical and flat sided porthole in the locomotive type of boiler.

Boiler Tube Cleaners. Contrivances used for removing the scale and soot from boiler tubes. In fire tube boilers the scale on the outside of the tubes is generally removed by scaling tools or chisels and scrapers. The scale on the inside of the tubes in water tube boilers is removed by wire brushes or by revolving scrapers or cutter heads attached to a small air or water driven turbine.

Boiler Tubes. Their use is described under water tube and fire tube boilers. Seamless drawn steel is the best material.

Boiler Tube Expander. A tool used to expand the tubes into the tube sheets, and also to bead over the ends.

Boiler Tube Sheets. The plates in a fire tube boiler into which the ends of the fire tubes or flues are expanded. The front tube sheet is usually that part of the boiler head which supports the forward end of the tubes and the back tube sheet is usually the plate forming the front end of the combustion chamber.

Boiler Wagon Top. A form of flat sides and rounded top in the way of a fire box or front end of some types of boilers.

Boiler Water Bottom. The space underneath the furnace occupied by water in an internally fired boiler.

Boiler Water Column. See Boiler Gage, Water.

Boiler Water Leg. The space occupied by water around the sides of a furnace in a boiler of the locomotive type and around the sides and back of a combustion chamber in a Scotch boiler.

Boiler, Water Tube. If the flames and hot gasses act on the outside of tubes through which water circulates the boiler is of the water tune type. In connection with the tubes horizontal drums are installed at the top and bottom. The feed water generally enters the top drum or drums and flows down through tubes to the lower drum or drums. It then returns through tubes about which the hot gages pass to the upper drum, where steam separates. The water level may be below the upper drum or at about half its depth. When the water level is below the top drum the tubes are called dry and when the water level is above the entrance of the tubes into the drum they are called wet. The tubes may be straight, curved, or bent, but in any case the fire grate is situated below so that the flames and hot gases may pass through them in rising. Surrounding the furnace, thus and part or the whole of the drums, a casing is fitted to prevent radiation. The water tubes have the advantage over the fire tubes in the following points, viz.: The weight of the boiler and the contained water is less. Steam may be generated more quickly. The danger from bad explosions is less. Less trouble from the ship’s structure in installation and in renewing worn or defective portions. High pressures are more easily provided for.

Bollards. A term applied to short metal columns extending up from a base plate which is attacked to a wharf or dock and used for securing the lines from a ship. Also, applied to timber posts extending above the level of a wharf for the same purpose. The bitts on a ship are frequently called bollards.

Bolster. A term applied to a piece of timber used as a support. A temporary foundation.

Bolt. A rod, usually of iron or steel, used as a fastening. With a few exceptions, such as drift bolts, a head or shoulder is made on one end and a screw thread is cut on the other.

Bolt, Carriage. Bolt with round head and square neck used on miscellaneous work.

Bolt, Clinched. A term applied to a bolt having one or both ends hammered over, after it is in place.

Bolt Cutter. A machine used to cut threads on bolts or rods. The work is held in a vise mounted on a carriage which travels along the bed of the machine while the die-head holding the cutting die revolves around the work. Belt cutters are made with single or multiple head.

Bolt, Deck. A. flat head bolt with square neck (plain or slotted head), used principally for securing deck planking through deck beams and plating.

Bolt, Eye. A rod of metal with one end having the shape of a torus or doughnut, and the other end having a screw thread cut on it or left smooth for riveting over. They are made with and without shoulders at the eye end.

Bolt Forcer. A machine designed to force in or start "driving fit" bolts such as those used in shaft couplings, etc. Common types of bolt forcer consist of a hydraulic cylinder and ram to which are attached side plates shaped in the form of a hook.

Bolt Hanger. A bolt cut with machine thread at one end and with lag screw thread at the other end, used on miscellaneous work.

Bolt Heading Machine. A machine used for upsetting bar stock to form bolt heads. Upsetting and heading machines are divided into two general classes, stop-motion an continuous-motion headers. The stop-motion headers have the greatest range and are primarily used for heading bolts, but are also used for all kinds of upset forgings. The continuous-motion headers are used only for heading rivets, carriage bolts, and short lengths of hexagon and square-head machine bots; they produce these parts at a much faster rate than is possible with a stop-motion header, but their range of work is limited.

Bolt, Holding Down. Also called tie rod. A rod of metal with a head on one end and a machine thread on the other, or a thread on both ends. They are usually used in the sides of deck houses, where they extend through the sill, up the sides between the ceiling and outside planking and through the top plates. Their purpose is to hold the deck house to the ship’s structure and prevent it from being carried away. Also applied to bolts used in securing machinery to their foundations.

Bolt, Lock. See Lock Bolts.

Bolt Pointer. A machine used for rounding or pointing the ends of bolts preparatory to cutting the thread. Its operation is similar to that of a bolt cutter.

Bolt, Rail. A bolt threaded at both ends. Used principally in fastening the ends of wood rails or planks together.

Bolt, Ring. An eyebolt having a ring worked through the eye. Ring bolts are made with lag screw ends for attachment to wood, with plain ends for riveting, and with ends fitted with a screw thread for nuts. They are also made with and without shoulders at the eye end.

Bolt Rope. See Rope, Bolt.

Bolt, Stay. See Stay Bolts.

Bolt, Stemson. A term applied to a bolt used to fasten a stemson to a stem or stern post.

Bolts, Stove. A small bolt with either a flat or round countersunk head and used for miscellaneous light work.

Bolt, Stud. A bolt threaded on both ends, one end of which is screwed into a hole drilled and tapped in the work for it. It is generally used where there is not sufficient access to use through bolts and where it is not practicable or possible to drill through the work.

Bolt, Through. A metal rod used as a fastening, with heads upset at both ends, after it is fitted in place. Also applied to bolt passing through the work as a distinction from stud bolts.

Bolt and Nut. A metallic pin threaded over a portion or all of its length and having one end upset or forged to form a head. The nut is a piece of metal drilled and threaded to fit and travel along the helical threads on the bolt by turning or revolving.

Bolt and Nut Machines. Machines designed to forge and thread bolts and nuts are known as bolt cutter, bolt forging or bolt header, bolt pointer, nut taper, etc.

Bolter Up. A workman who fastens the steel work in place with bolts, preparatory to and in order to facilitate its permanent fastening or riveting up.

Bolting Up. Securing parts of a structure in proper position by means of bolts and nuts preparatory to riveting.

Bone in Her Mouth. An expression used in speaking of a ship making considerable speed. It refers particularly to the foam on the bow wave.

Bonjean Curves. Curves of areas of transverse sections and curves of moments of the same above the base line.

Bonnet. A term applied to a valve cover. In most valves the bonnet is designed to enclose and guide the valve stem.

Booby Hatch. See Hatch, Booby.

Boom. A term applied to a spar used in handling cargo, or as the lower piece of a fore-and-aft sail.

Boom Chock. See Cock, Boom.

Boom Crutch. A term applied to a structure built up from a deck to support a boom when it is not in use.

Boom Mountings. All metal bands, collars and other gear secured to a boom to connect it to a mast or for attaching ropes to the boom.

Boom Stowage. Provision for stowing the booms when not in use and consisting essentially of boom crutches or chocks.

Boom Table. An outrigger attached to the mast or a structure built up around a mast from the deck to support the heel bearings for booms. Boom tables are necessary to provide proper working clearances when a number of booms are installed on one mast.

Booster Pump. See Pump, Transfer.

Boot-Topping Paint. See Paint.

Boring Bar. A portable, heavy duty tool used for boring and facing where true alignment is of prime importance. These tools usually consist of a heavy shaft which is passed through the part to be bored and supported by bearings which are adjusted to the proper alignment. A cutter head which holds the cutting tools is fitted to slide along the shaft on a feather and the travel or feed of the cutter head is regulated by a feed-screw recessed into the shaft. The shaft is rotated by mechanical means and the feed is regulated by hand or automatically depending on the type of tool. Boring bars are used in a shipyard for boring, re-boring, facing or grooving rudder post gudgeons, stern tube bearings, cylinders, turbine engine casings, etc.

Boring Machine. Boring machines may be divided into two general classes, vertical and horizontal. The standard designs of these machines are not intended exclusively for boring, as the name indicates, and very often boring constitutes a small part of the work. For instance, vertical boring machines are very generally used for turning cylindrical, flat and tapering surfaces, whereas many machines of the horizontal type may be used for drilling, milling and flange facing. Because of this fact, the names vertical, boring and turning machines, and horizontal boring, drilling and milling machines, are frequently applied to these two classes of machine tools.

Bosom Piece. A short piece of angle bar used as a butt strap or connecting piece. Unlike the heel piece, its flange projects in the same direction as the bars it connects and it is fitted in the bosom or between the flanges of the bars it joins.

Boss Barrel. A term applied to the plating around the boss and stern tubes.

Boss Frame. See Frame, Boss.

Boss Plate. See Plate, Boss.

Boss, Propeller. See Propeller, Boss.

Boss, Propeller-Post. That portion of the propeller post that is swelled out to receive the stern tube.

Bottom. That portion of a vessel’s shell between the keel and the lower turn of the bilge. In Bottom used with reference to the ship as a whole.

Bottom, Outer. A term applied to the bottom shell plating in a double bottom ship.

Bottom Strake. See Strake, Bottom.

Bottomry. The business of leasing or mortgaging ships.

Bound. Confined, Destined.

Outward Bound. Bound for the sea.

Homeward Bound. Bound for the vessel’s home port.

Tide Bound. Unable to progress because of adverse tide.

Wind Bound. Unable to make progress because of adverse winds.

Bow. The sides of a vessel at and for some distance abaft the stem, designated as the right hand, or starboard bow, and the left hand, or port bow.

Bow Chock. See Chock, Bow.

Bow Chock Plate. A plate fitted for the purpose of taking a bow chock. This plate is fitted near the stem and above the forecastle deck.

Bow, Clipper. A long, curved overhanging bow, such as was characteristic of the fast wooden sailing ships built in the United States during the middle of the nineteenth century.

Bow Grace. A term applied to the fenders suspended over the bow of a ship as protection against ice.

Bow Ornament. A figurehead or ornament fitted on the bow or bobstay piece.

Bow Plate. See Plate, Bow.

Bow Plating. A term applied to the shell plating in the bow of a vessel.

Bow Port. See Port, Bow.

Bow Rope. A rope leading from a vessel’s bow to another vessel or to a wharf for the purpose of hauling her ahead or securing her. Also known as "bow-line" or "bow-fast."

Bow Wave. The wave thrown up at the bow of a vessel as she plows through the water.

Bower Anchors. See Anchor, Bowers.

Bowlines. Ropes connected by bridles to the leeches of square sails and leading forward for use in hauling the weather leech well forward in order to hold the wind when sailing close-hauled. When sailing in this manner a vessel is said to he on a bowling, that is, close to the wind.

Bowsprit. A spar projecting forward over the bow for the purpose of holding the lower ends of the head sails.

Bowsprit Cap. An iron band fitted on the forward end of the bowsprit.

Box Keelson. See Keelson, Box.

Boxing the Compass. The enumeration, in regular sequence, of the points and fractional points of the mariners’ compass.

Box, Starting. See Starting Box.

Brace. A rope attached to the yard arm. By means of this rope the position of the yard arm may be altered in a horizontal plane. This operation is known as trimming sail.

Bracing, Boiler. See Boiler Bracing.

Bracket, Boiler. See Boiler Bracket.

Bracket, Frame. A bracket connecting the side frame to the margin plate of a double bottom.

Bracket, Plate. A plate, usually of triangular shape, provided for the purpose of rigidly connecting structural members.

Brackets, Beam. A term applied to small steel plates, usually of triangular shape, used to fasten the deck beams to the frames at the side of a vessel. Also used to fasten deck half beams to fore and aft bulkheads, casings or coamings.

Brails. Ropes rove through blocks fastened to a spar and attached to the leech of the sail. The overhauling of these ropes gathers the sail up against the spar.

Breadth (extreme). The maximum breadth measure over plating or planking, including beading or fenders.

Breadth, Molded. The greatest breadth of a vessel, measured from the heel of frame on one side to the heel of frame on the other side.

Breadth, Register. The breadth of the broadest part on the outside of the vessel shall be accounted the vessel’s breadth of beam, and should be taken either by plumb lines let full so as to touch the sides of the vessel or by other practical means.

Breaker. A wave breaking violently over or against a reef, rock, etc., lying at or below the surface of the water

Break in. To produce a deformation in the plating at a seam by driving the calking edge down too hard.

Break of Poop or Forecastle. The point at which the partial decks known as the poop and forecastle are discontinued.

Breakwater. A term applied to plates or timbers fitted on a forward weather deck to form a V-shaped shield against water that is shipped over the bow.

Breast. Rounded bows are sometimes called the breast of a vessel. To breast the sea is to meet the waves bows on.

Breast Hook. See Hook, Breast.

Breeches Buoy. A life saving contrivance for rescuing persons from a wreck. It consists of a ring buoy fitted with a canvas trunk similar to the upper part of a pair of breeches.

Bridge. A high transverse platform, often forming the top of a bridge house, extending from side to side of the ship, and from which a good view of the weather deck may be had. An enclosed space called the pilot house is erected on the bridge in which are installed the navigating instruments, such as the compass and binnacle, the control for the steering apparatus and the signals to the engine room. While the pilot house is generally extended to include a chartroom and sometimes staterooms, a clear passageway should be left around it. As the operation of the ship is directed from the bridge or flying bridge above it, there should also be clear open passage from one side of the vessel to the other.

Bridge, Connecting. A narrow walkway fitted between the poop and bridge decks or between the bridge and forecastle decks. This walkway is common on oil tankers on account of the slippery condition of the upper deck and is particularly desirable where bulwarks are not fitted.

Bridge Deck. See Deck, Bridge.

Bridge Deck Stringer. See Stringer, Bridge Deck.

Bridge Deck Stringer Bar. See Stringer, Bar.

Bridge Gunwale. See Gunwale, Bridge.

Bridge House. A term applied to an erection or superstructure fitted about amidship on the upper deck of a ship. The officers’ quarters, staterooms and accommodations are usually located in the bridge house.

Bridge House, Closed in. A bridge house having bulkheads at both the forward and after ends.

Bridge House Frame. See Frame, Bridge House.

Bridge House, Open. A bridge house having the forward and after ends open.

Bridge, Long. See Bridge, Connecting. A fore and aft walkway between deck houses.

Bridge, Navigating or Flying. The uppermost platform erected at the level of the top of pilot house. It generally consists of a narrow walkway supported by stanchions, running from one side of the ship to the other and the space over the top of the pilot house. A duplicate set of navigating instruments and controls for the steering gear and engine room signals are installed on the flying bridge so that the ship may be navigated in good weather from this platform. Awnings erected on stanchions and weather clothes fitted to the railing give protection against sun and wind.

Bridge Piece. See Arch Piece.

Bridge, Pilot. See Bridge, Navigating or Flying.

Bridge Sheer strake. The strake of outside plating adjacent to the bridge deck.

Bridge Warping. A platform erected at the after end of a vessel for the use of the navigating officers when docking.

Brig. A vessel having two masts, fore and main. Both of these are square rigged but the main mast has in addition a gaff main sail.

Brigantine. A vessel having two masts, fore and main. The foremast is square and the main mast fore-and- aft rigged.

Broach. To suddenly veer into the wind laying the sails aback, thus exposing the vessel to danger of capsizing; said usually of a vessel running with the wind quartering.

Broken Backed. Said of a vessel when, owing to insufficient longitudinal strength, grounding, or other accident, her sheer is reduced or lost, thereby producing a drooping effect at both ends. (See Hogged).

Brow. A small curved angle or flanged plate fitted on the outside of the shell of a ship over an air port to prevent water running down the ship’s side from entering the open port.

Bucket, Pump. See Pump, Bucket.

Bucket Valve, Pump. See Pump, Bucket Valve.

Bucklers. Generally, though not exclusively, applied to devices designed to close chain pipes, hawse pipes, and turret gun port openings.

Built-in Furniture. See Furniture, Built-in.

Built-up Frame. Described under Frame.

Bulb Angle Bar. An angle bar having a bulb or swell worked along the edge of one flange. In ship work it is used for frame bars, light bulkhead stiffeners and deck beams. The size is denoted by dimensions of cross section and weight per running foot.

Bulb Angle Frame. See Frame, Bulb Angle.

Bulb Plate. A narrow plate, generally of mild steel, rolled with a bulb or swell along one of its edges. In ship work it is used for bilge keels, hatch coamings, built-up beams, etc.

Bulb, Tee. A rolled shape, generally of mild steel, having a cross section shaped like the letter T, with a bush formed along the outer edge of the web. In ship work it is used for bulkhead stiffeners, deck beams, etc. The size is denoted by dimensions of cross section and weight per running foot.

Bulk Cargo. Cargo made up of commodities such as oil, coal, water, grains, etc.

Bulkhead. A term applied to any of the partition walls used for subdividing the interior of a ship into the various compartments. The main partition walls also serve as strength members of the ship’s structure and as a protection against water passing from one compartment to another.

Bulkhead, After Peak. A term applied to tile 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 Bounding Bar. A bar used for the purpose of connecting the edges of a bulkhead to the tank top, shell, decks, or to another bulkhead. Angle bars are generally used for this purpose as both flanges are easily caulked.

Bulkhead, Boiler Room. A term applied to a bulkhead bounding the boiler space.

Bulkhead, Cargo Hold. A term applied to a bulkhead bounding a cargo hold.

Bulkhead, Center Line. A fore and aft or longitudinal bulkhead erected on the center line or in the same plane as the keel. Also a reference line scrived on a transverse bulkhead to indicate the center of the ship.

Bulkhead, Coal Bunker. A term applied to a coal bunker partition wall. These bulkheads, when they serve no other purpose than enclosing coal bunkers, need not be made watertight.

Bulkhead Coaming. See Coaming, Bulkhead.

Bulkhead, Collision. The foremost transverse watertight partition in a ship that extends from the bottom of the hold to the freeboard deck. The principal object of this bulkhead is to keep the water out of the forward hold in case of a collision or damage to the bow.

Bulkhead, Corrugated. A bulkhead made from plates of corrugated metal or by flat plates alternately attached to the opposite flanges of the bulkhead stiffeners. Corrugated metal bulkheads are used around staterooms and quarters. Corrugated cargo hull bulkheads are generally constructed of flat plates alternately attached to opposite flanges of the stiffeners, but they are weak in compression.

Bulkhead, Deck. The uppermost continuous deck to which all transverse watertight bulkheads are carried. The term is used in connection with the method of subdividing merchant ships described in the Report of the Committee appointed by the president of the British Board of Trade.

Bulkhead, Engine Room. A term applied to a bulkhead bounding the machinery space.

Bulkhead, Fore Peak. The bulkhead nearest the stem, which forms the after boundary of the fore peak tank. When this bulkhead is extended from the bottom of the ship to the weather deck it is also called the collision bulkhead.

Bulkhead Frame. See Bulkhead Bounding Bar.

Bulkhead Liners. See Liners, Bulkhead.

Bulkhead, Longitudinal. A partition wall of planking or plating running in a fore and aft direction. Fore and aft bulkheads are very common on warships.

Bulkhead, Partial. A term applied to a bulkhead that only extends to a portion of the way across a compartment. They are generally erected as strength members of the structure.

Bulkhead Plate. This term may be applied to any plate in any strake of bulkhead plating.

Bulkhead, Poop. The wall erected at the forward end of the poop running between the upper and poop decks.

Bulkhead, Recess. A bulkhead bounding a compartment that is recessed off from a main compartment. This is frequently done at the after end of the machinery space to accommodate the thrust block.

Bulkhead, Screen. A term applied to a light non-watertight bulkhead fitted between the engine and boiler rooms. This bulkhead is fitted to keep the dust and heat out of the engine room, and is often constructed around the after ends of the boilers.

Bulkhead Stiffeners. A term applied to the beams or girders attached to a bulkhead for the purpose of supporting it under pressure and holding it in shape. These steering beams are usually spaced from about two to four feet apart and are attached to the shell, tank top and decks by brackets or lugs. Vertical stiffeners are most common on bulkheads, but horizontal stiffeners or a combination of both may be used.

Bulkhead Stringer. A term sometimes applied to horizontal bulkhead stiffeners. A horizontal girder running across and riveted to a bulkhead for stiffening purposes. The stringer is connected at the ends by a gusset bracket to the side stringers or shell.

Bulkhead, Structural. A partition wall that is designed to perform the work of a strength member of the ship’s structure. Most all of the main water tight bulkheads are strength members.

Bulkhead Stuffing Box. See Stuffing Box, Bulkhead.

Bulkhead, Temporary. Any partition wall erected to temporarily divide a compartment or for the purpose of keeping out water until a permanent bulkhead is repaired or installed.

Bulkhead, Transverse. A partition wall of planking or plating running in an athwartship direction across a portion or the whole breadth of a ship. The principal function of transverse bulkheads is to divide the ship into a series of watertight compartments so that any rupture of the shell will not cause the loss of the vessel. The best practice is to fit transverse bulkheads near enough together so that the admission of the sea to any two adjacent compartments will still leave the ship enough reserve buoyancy to float. Transverse bulkheads also serve as efficient strength members and are important in preserving the transverse shape of a vessel. These bulkheads also serve the purpose of subdividing the cargo space and quarters into compartments of desirable length.

Bulkhead, Trunk. A term applied to the casings or partition that forms an enclosure running from deck to deck and surrounding hatch openings.

Bulkhead, Wash. A non-watertight divisional bulkhead usually erected on the center line of deep tanks and peak tanks. The peak tanks are generally really narrow at the bottom and the wash bulkheads installed in them need not be constructed but a few feet down from the tank top. They should be strongly built to withstand the flow of liquid caused by the motion of the ship.

Bulkhead, Watertight. A partition of planking or plating reinforced where necessary with stiffening bars and capable of preventing the flow of water under pressure from one compartment to another. To do this all seams, butts or connections of the plating or planking must be efficiently calked and the strength of the structure must be sufficient to stand up under pressure.

Bulkhead, Wire Mesh. A partition built up of wire mesh panels.

Bull Ring. See Follower Plate, Junk Ring, etc.

Bull’s Eye. An annular piece of hard wood with a large hole for a bowline or other rope to pass through and a score or groove around it for slicing into a strap. It is frequently termed a lizard; the name of a lantern, particularly its lens; the center of a target. A round window.

Bulwark. A term applied to the strake of shell plating or the side planking above a weather deck. It helps to keep the deck dry and also serves as a guard against losing deck cargo or men overboard. Where bulwarks are fitted it is customary to provide openings in them which are called freeing ports, to allow the water that breaks over to clear itself. Bulwarks interfere with the rapid handling of cargo as care must always be taken to hoist everything clear of its top.

Bulwark Frames. See Frames, Bulwark.

Bulwark Plate. Any plate used in a bulwark strake of plating.

Bulwark Port. See Port, Bulwark, Clearing or freeing.

Bulwark Stanchions. See Stanchions, Bulwark.

Bumboat. A boat employed in carrying supplies for sale to vessels, the term being a corruption from bombard, the vessel in which beer was formerly carried to soldiers on duty.

Bumped. A term applied to a convex head on the end of a water tank or boiler.

Bung Starter. A heavy bat or stave used for strike- in casks or barrels on either side of the bung in order to start or loosen the bung.

Bunk. A built-in berth or bed. The term is usually applied to a berth in the sailor’s or steerage quarters.

Bunker Frame. See Bulkhead Bounding Bar.

Bunker, Hold. See Hold, Bunker.

Bunker, Side. See Side Bunker.

Bunker, Athwartship. See Athwartship Bunker.

Bunkers. Stowage spaces for either oil or coal fuel.

Bunkers, Coal. The spaces or compartments of a ship in which is stowed the coal used as fuel for the boilers.

Buntlines. Ropes toggled to the foot of square sails some distance from the center for use in hauling the foot of the sail up to the yard for convenience in furling. They reeve through blocks at the masthead and thence down to the deck forward of the sail.

Bunting. A thin, coarse woolen material used for small pennants and for flags.

Buoy. A term applied to a floating object that is moored or anchored so that it remains at one place. Buoys are used for marking the place on the water where a ship is sunk, where reefs are below, where the edges of the channel are, or to provide means for mooring a ship at a desired position.

Buoy, Life. See Life Buoy.

Buoy, Life Ring. See Life Ring Buoy.

Buoy Rope. See Rope, Buoy.

Buoy Mooring. A term applied to a floating object that is anchored in a harbor or roadstead for the purpose of providing a mooring for a vessel. These buoys are commonly made in the shape of rectangular steel tanks having a heavy ring fitted on the top.

Buoyancy. 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 buoyancy power of that part of a vessel’s hull which is above the load waterline.

Buoyancy, Working. The buoyancy acting at any given time to support a vessel in her floating condition. The term is used in contrast to reserve buoyancy, a portion of which becomes working buoyancy in the event of increased load or of damage resulting in the admission of water to the hull below the waterline.

Burden. A vessel’s carrying capacity expressed in long tons.

Burgee. A triangular or swallow-tailed flag used as a distinguishing pennant by yachts and merchant vessels. In some cases it bears the name of the vessel, in others the initials or some device of the company or firm owning or operating the vessel.

Burners. Men who operate gas torches which sever or trim material by burning it away or which heat the edges of a joint so they flow together and unite to form one piece.

Burners, Boiler Oil. See Oil Burners.

Burring Machine. A machine designed to remove burrs from hot pressed nuts.

Burton. A tackle used for various purposes, as for hoisting a topsail aloft, supporting a yard, etc. A top-Burton is hooked to a topmast pendant and used for setting up rigging, for securing lower yards when rigged for handling weights, and for any other purpose requiring a tackle placed aloft. It is usually rove as a luff, with a fall of sufficient length to be led out on deck when the lower block is at the deck. The fall of the main top-Burton is the longest piece of running rigging on a vessel.

Bus Bar. An electrical conductor. A metal bar of low electrical resistance commonly used on the rear of power switchboards for carrying current between electrical apparatus.

Bushing, Stern Tube. See Stern Tube Bushing.

Bussa. A metal contraption, rather like a coiled spring, used in the West Country of England during the 19th century for cooking pilchards.

Bussa Pot. Also called a pilchard pot (and not to be confused with a Great Crock). It is a deep, round pan, with vertical sides and internal glaze, used in Devon and Cornwall for salting pilchards.

Butt Joint. See Joint, Butt.

Butt Plate. See Plate, Butt.

Butted Frames. See Frames, Butted.

Butterfly Valve. See Valve, Butterfly.

Buttocks. The traces formed by the intersections of longitudinal vertical planes parallel to the central longitudinal vertical plane of the ship, with the forward and after surface of the ship’s hull. These traces when occurring in the forebody are called bow lines, and when in the after body, buttock lines. However, the term buttocks is often used to denote both bow and buttock lines.

Butts, Shift of. A term applied to the arrangement of the butt joints in plating. These joints in shell plating should be so shifted that the adjacent strakes of plating have their butts at least two frame spaces apart. Also the butts in any frame space for the complete number of strakes should be made as few as possible, say every six or seven strakes.

Butt Straps. A term applied to a strip of plate serving as a connecting strap between the butted ends of plating. The strap connections at the sides are called seam straps.

Butted Frames. See Frames, Butted.

Buttock. The rounded portion of the lower stern. This term is also applied to fore and aft sections on the line plan.

By-Pass Valve. See Valve, By-Pass.

By the Board. Overboard, over the side, off the decks and into the water.

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