Ship Construction Ions

MASSACHUSETTS MARITIME ACADEMY MARINE TRANSPORTATION DEPARTMENT SHIP CONSTRUCTION (MT0644) GLOSSARY OF SHIPBUILDING DEFINITIONS l. Access hole: Opening in any part of ship's plating used as a passageway while ship is under construction or a passageway between sections of a double bottom tank. page 66 2. Advance: (Reference all maneuvering characteristics from Bowditch Vol. II) The distance a vessel continues to travel on a course before responding to a change of helm. The distance that the ship has advanced in a direction parallel to the original course measured from the point where the helm was put over. page 84 3. Afterpeak: The compartment in the narrow part of the stern, aft of the last watertight bulkhead large effect on the trim of the vessel M = w x d. 4. Air escape hole: An aperture cut in the top of solid floors or tanks to prevent air lock from inhibiting the free flow of liquid. page 64 5. Air port: A circular window with hinged glass in the ship's side of deckhouse, for light or ventilation; also called porthole. 6. Angle clip: A short piece of angle bar used for attachment. Examples include sweat battons (Cleat), back boards, etc. page 33 7.

Anneal:

To relieve locked-up stresses by heating and gradual cooling.

8. Appendages: The portions of the vessel extending beyond the main portion of the hull outline including such items as the rudder, struts shafting, boss or bilge keels. 9. Aperture: The space provided between rudderpost and propeller post for the propeller. page 75 & 81 10. Assemble: To put together sections of the ship's structure on the skids, in advance of erection on the ways. 11. Arch Line:

Line used to scribe a curved portion of any structure

12. Auxiliaries:

Various winches, pumps, motors, and other small engines required on a ship.

13. Backing angle: A short piece of angle for reinforcing the butt joint or splice of two angles, placed behind the angles joined. page 33 14. Balk:

A piece of timber from 4" to 10" square

15. Ballast: (Indicate the materials employed) Any weight or weights (usually sea water) used to keep the ship from becoming top-heavy or to increase its draught or trim. Materials: Fuel oil, Massachusetts Maritime Academy

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salt water, fresh water, poured cement, cement blocks, ingots, driller's mud. 16. Base line: The fore and aft datum line from which all vertical heights are measured. On riveted hulls its location is usually parallel to the top edge of the garboard strake. On welded hulls, it usually parallel to the top edge of the flat plate keel. however since this is a designer's option the lines plan should be consulted to determine its exact location. 17. Beam: An athwartship horizontal member supporting a deck or flat. Also, the extreme width of the ship. page 82 18. Beam, deck: An athwartship horizontal member supporting a deck or flat. The usual depth of a beam bracket is 2 1/2 times the depth of the beam. page 82 19. Beam, hatch: Portable beam across the hatch to support covers; also, strong beam at ends of hatch. Usually I beam stock. 20. Beam, hold: them.

Beams in a hold, similar to deck beams, but having no plating or planking on

21. Beam, knee: End of steel deck beam that is split, having one portion turned down and a piece of plate fitted between the split portions, forming bracket for riveted connection to side frame. 22. Bracket, margin:

A bracket connecting the frame to the margin plates. page 64

23. Beam, panting: An athwartship horizontal member supporting a deck or flat fitted to resist panting stress forward or aft. 24. Bearding (Bearding line): A term applied to the line of intersection of the shell plating and the stem or sternpost. 25. Belt Gauging: Taking readings of plate thickness around several complete transverse sections of the ship hull plating. 26. Bending Moment: along the hull girder.

The moment of force which is generated by the position of weights

27. Bending rolls: A machine in which power-driven steel rollers are used to give cylindrical curvature to plates. 28. Bending slabs: Heavy cast-iron perforated slabs arranged to form a large floor on which frames, etc., are bent, after heating in a furnace. Fig. 74, page 143 29. Berth: A place where a ship is docked or tied up; a place to sleep; a bunk. Distance between bulkheads. 30. Between decks:The space between any two continuous decks; also called 'tween decks. 31. Bevel: The angle between the flanges of a frame or other member. Greater than a right angle (90°) is called an open bevel; less than a right angle (90°) is called a closed bevel. Massachusetts Maritime Academy

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32. Bilge: (Describe side bilges & bilge well systems) Curved section between the bottom and the side of the ship; the recess into which all water drains. Side bilge system is similar to a gutter or trough at the sides of the vessel. Bilge well systems in common use today water runs aft and is pumped out of the well or sump through the bilge system. -j3. Bilge keel: A fin fitted on the bottom of a ship at the turn of the bilge to reduce rolling. It commonly consists of a plate running fore and aft and attached to the shell plating by welding or by angle bars. It materially helps in steadying a ship and does not add much to the resistance to propulsion. page 82 & Fig. 8, page 17 34. Bitumastic: elastic bituminous cement used in place of paint to protect steel in ballast tanks, hollow rudders, chain lockers. 35. Boiler chock: Stay brace to prevent for-and-aft movement of boilers, also called ramming chock. 36. Boiler saddle: Support for boilers. 37. Bolster Plate: A plate adjoining the hawse hole to prevent chaffing of a hawser against the cheeks of the ship's bow. page 83 38. Booby hatch: Watertight covering over an opening on deck of a ship for a stairway or ladder. 39. Bottom, double: The general term used for the space between the outer bottom and the tank top and margin plates. It extends transversely from bilge to bilge and longitudinally- from the forepeak to afterpeak tanks. The double bottom is subdivided into a number of compartments called tanks which contain water, fuel or ballast. 40. Bottom, inner: Plating forming the top part of the double bottom. In cargo holds it is the surface upon which the cargo rests. Also referred to as the tank top. 41. Bottom, outer: The bottom plating on the exterior of the ship's hull. 42. Bounding Bar: A bar connecting the edges of a bulkhead to the tank top, shell, decks, or another bulkhead 43. Bosom piece: A short piece of angle riveted inside a butt joint or two angles; butt strap for angle bars@; splice piece. 44. Boss:

The curved swelling portion of the ship's hull around the propeller shaft. page 75

45. Boss plate: outboard. page 75

Shell plate covering curved portion of hull where propeller shaft passes

46. Bracket: A triangular plate used to connect rigidly two or more parts, such as deck beam to frame or frame to margin plate. page 69 Massachusetts Maritime Academy

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47. Bracket, bilge: A flat plate welded or riveted to the tank top or margin plate, and to the foot of the frames in the area of the bilge; sometimes called a margin bracket. page 65 48. Bracket, deck beam: A triangular flat plate welded or riveted to the shell frame and the deck beam where they terminate. 49. Bracket, tangency: A bracket whose inner face is curved rather than straight to distribute weight or stress over the face of the bracket by increasing the surface area rather than at the corners. 50. Bracket, tripping: load. 51. Braze:

A bracket use to prevent structural members from collapsing under

To join certain metals by the use of a hard solder. page 41

52. Breasthook: A flanged plate bracket joining port and starboard side stringers at their forward end. page 79 53. Breakwater: An athwartships or V-shaped coaming abaft of the hawse holes acting as a protection against shipping water over the weather deck which channels the water toward the sides of the vessel. 54. Brow: A small access ladder entering the vessel at 90°. A small plate fitted over an opening to prevent drainage from entering. 55. Brow plate: Any ramped sloping plate around an access opening which facilitates the handling of cargo over an obstruction. 56. Building slip:

Place where the ship is built before launching.

57. Bulb angle:

Angle shape reinforced at one tow. pages 32-33

58. Bulb plate:

Narrow plate reinforced on one edge.

59. Bulb tee: T

bar with toe of web reinforced.

60. Bulkhead: A vertical steel partition corresponding to the wall of a room, extending either athwartship or fore and aft. 61. Bulkhead, collision: First watertight bulkhead from bow of ship.page 83 62. Bulkhead, screen: A bulkhead, dust tight but not watertight, usually placed between the engine and boiler rooms 63. Bulwark: The strake of shell plating above a weather deck. It helps to keep the deck dry and also serves as a guard against losing deck cargo or men overboard. 64. Buoyancy:

(Describe Archimedes’s Principle) Ability to float; upward force of water

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pressure. A body that floats displaces an equal volume or weight of liquid. 65. Buoyancy reserve: The additional buoyancy that would result if that part of the vessel's hull above the load water line were immersed. page 28 66. Buttock Line: The intersection of a fore-and-aft vertical plate with the molded form of the ship. Rounded area near the stern. pages 30-31 67. Butt strap: A strip or strap that overlaps both pieces, serving as a connecting strap between the butted ends of plating. 68. Camber: The rise or crown of a deck, athwartship provides a mean for water to drain from the deck. page 28 69. Capstan: A revolving device in the vertical axis used for heaving in mooring lines or anchors. 70. Cargo, Ad valorum: A cargo of high value. 71. Cargo batten: Strip of wood used to keep cargo away from steel hull. 72. Cargo, port: Opening in a ship's side for loading or unloading cargo. Often referred to as a side port. 73. Cargo, deadweight: Any cargo with a stowage factor of 40 cubic feet to the ton or less. 74. Cargo, measurement: more.

Any cargo with a stowage factor of 41 cubic feet to the ton or

75. Cargo, special: A cargo of high value which is easily pilfereble and requires special care in handling to prevent theft. 76. Carling: (Also called carlines) Fore-and-aft member at side of hatch, extending across ends of beams where cut to form hatch. 77. Casing: Bulkheads enclosing portion of vessel, such as engine or boiler casing. Also, covering for parts of machinery, such as engine-cylinder casing. 78. Casting: (Construction & Maneuvering) To turn a vessel in a particular (opposite heading in her own length. An object made by pouring molten metal into a pre-molded form or shape and allowing it to cool. 79. Caulk (Calk): (Describe materials used) To make a joint watertight. 80. Cavitation: As the propeller turns a low pressure area is formed on the leading and trashing edges of the blades, causing a loss of propulsion efficiency, pitting of the blades and vibration. 81. Center, buoyancy: The point through which all of the upward forces of buoyancy act. It is the geometric center of the immersed portion of the hull or 1/2 the draft (O.53 for Merchant type hulls). Massachusetts Maritime Academy

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82. Center, gravity:The point through which all of the downward forces of gravity are said to act or the center of the mass. Its position is determined solely by the position. of weights on board. 83. Center, line: 84. Ceiling: protection.

The fore-and-aft middle of the ship, from stem to stern.

A surface usually wood, placed over the tank tops in the way of the hatch for

85. Chaffing plate: Bent plate for minimizing chafing of ropes, as at hatches. 86. Chain locker: Compartment in forward lower portion of ship in which anchor chain is stowed. 87. Chain pipe: pipe.

Pipe for passage of chain from windlass to chain locker. Al-so called spill

88. Chamfer: A bevel surface formed by cutting away the angle of two (2) faces of a piece of wood or metal89. Classification Society: An institution that supervises the construction of vessels under established rules, tests all material for hulls, machinery, and boilers, proof-tests all anchors and chains, and issues a certificate of classification. 90. Cleat: A fitting having two arms or horns around which ropes may be made fast. A clip on the frames of a ship to hold the cargo battens in place. 91. Coaming hatch:A vertical boundary around the hatch or skylight used the reduce stress in that area. 92. Cofferdam: Narrow empty space between two oiltight bulkheads to prevent leakage of oil into compartments adjoining oil tanks. page 68 93. Companion way: for the crew's use.

An access hatchway in a deck, with a ladder leading below, generally

94. Compartment: A subdivision of' space or room in a ship. 95. Construction, longitudinal: Method of construction which provides greater longitudinal strength where the frames are more widely spaced and more longitudinals are added. page 61 96. Construction, transverse: Method of construction which provides greater transverse strength where the longitudinals are more widely spaced and more frames are added. The cargo spaces are more amenable to the stowage of general cargo because they are squared-up. page 60 97. Cooper Plate: Repair plate in an area. Cooper, a person who repairs packing materials such as crates, cartons, or barrels. Massachusetts Maritime Academy

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98. Counter: Overhang of stern of a ship. 99. Countersink: 100. Cowl:

The taper of a rivet hole for a flush rivet.

Hood-shaped top of ventilator pipe.

101. Cover Plate: In wooden shipbuilding a horizontal fore & aft timber which forms the outer limit of the upper deck at the sides. Also called covering board. 102. Crack arrestor: A slot cut or a hole bored near the area of probable high stress to stop a crack should one start in the area of stress. The theory being that the intense stress in the apex of a crack will lessen when the surface area of the apex is increased. 103. Cradle: A form on which furnaced plates are shaped. The support in which a ship lies during launching, called launching cradle. 104. Crater: A cup-shaped depression in a weld. The arch tends to push the molten metal away from the center of the point being welded, thus forming a crater 105. Crossover: The system of valves and cargo lines in the bottom piping network of a tanker that connects one section of a cargo tanks to another. 106. Cubic, bale: The capacity of a vessel's cargo spaces in cubic feet measured to the inside of the cargo battens, to the tank top ceiling, and the underside of the deck beams. Ten percent of the bale capacity is usually deducted to obtain the effective capacity for general cargo. Bale cubic is the best indicator of the cargo carrying capacity of the vessel; it is expressed in cubic feet of cargo space. Also called bale measure or bale cubic. 107. Cubic, grain: The capacity of a vessel's cargo spaces in cubic feet measured to the outside of the frames (skin), top of the ceiling, top of the deck beams including hatchways. Also called grain cubic. 108. Dagger: A piece of timber that is fastened to the poppets of the bilgeway and crosses them diagonally to keep them together. Dagger applies to anything which stands in the diagonal position. page 80 109. Dead flat: The portion of a ship's form or structure that has the same transverse shape as the midl3hip section. Also referred to as Parallel Mid-body or Square body, page 30-31 110. Dead rise: Rise or slant up athwartship of the bottom of a ship from the keel to the bilge. page 28 111. Deck, bulkhead: The uppermost continuous deck to which all the main transverse watertight bulkheads are carried. This deck should be watertight in order to prevent any compartment that is open to the sea from flooding the one adjacent to it. 112. Deck Boat:

The deck on which the lifeboats are stowed.

114. Deck Embarkation: Deck from which passengers and crew are loaded into the lifeboats. Massachusetts Maritime Academy

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115. Deck, freeboard: The deck to which the watertight bulkheads are carried and the deck from which freeboard is measured. 116. Deck, house:

Shelter built on deck, not extending to the sides.

117. Deck, hurricane:

(Wing deck) Decks which extend from the bridge deck.

118. Deck main:

The principal deck, usually that immediately below weather deck.

119. Deck, orlop:

A partial deck in hold.

120. Deck, shelter: A deck similar to an awning deck, differing from it in that the 'tween deck space below it is not included in the vessel's gross registered tonnage. This omission is allowed under existing tonnage laws provided that somewhere in the deck an opening referred to as a "tonnage opening" is fitted without a permanent means of closing it, and that no part of the 'tween deck space under said shelter deck is partitioned off or enclosed in a permanent fashion. SHELTER DECK SHIP: A type of vessel with a full length superstructure above the principle deck, the superstructure being of lighter construction that would be required for a ship of full scantlings to the uppermost continuous deck. The principle deck may be defined as the uppermost continuous deck to which the watertight bulkheads are carried... This is considered a deck which has a permanent means of closing and can therefore be considered the freeboard deck. 121. Deck, spar:

Weather deck above the upper most continuous deck or shelter deck.

122. Deck, stringer: The strake of' plating that runs along the outer edge of a deck. 123. Deck, weather: Full deck with no overhead protection, watertight. 124. Deck, well: A sunken deck on a merchant vessel, fitted between the forecastle and a long poop or continuous bridge house or raised quarter deck. 125. Declivity: Inclination of the ways on which a ship slides during launching. 126. Deflection: The amount of bending. The amount that the pendulum is moved during the inclining experiment. 127. Diameter Final: With reference to a ship's turning circle, the perpendicular distance between the tangent to the curve at the point where the ship has swung through 1800 and that where it has swung through 360°, should the ship continue turning indefinitely with the same speed and rudder angle She will continue to scribe this circle. Always less than the Tactical diameter. page 84 128. Diameter Tactical: The perpendicular distance from the original course to the position where a ship has turned through 180°, after the helm is put over. Always greater than the Final diameter. 129. Diameter Turning: (Turning Circle draw & name parts) The path approaching in the form of a circle described by a vessel with helm at full angle while turning through 32 points of the compass with the engines at full speed. The approximate Massachusetts Maritime Academy

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diameter of the turning circle is about 6 times the length of the ship for single screw cargo vessels and about 3 to 4-1/2 times for twin screw vessels the turning circle shows the path traversed by the center of gravity of lateral resistance (pivot point) of the vessel 130. Die: A tool, having several cutting edges, used for cutting threads. In drop-forging work, a template tool used to stamp a piece of work in one operation. 131. Docking Keel: Keel on each side, and in plane of regular keel, used to distribute the weight in dry dock in the case of large ships. (Seldom used except on largest naval ships). 132. Docking Plug: A screwed set pin of from 7/8" to 1 1/4" in diameter made of brass and fitted in the garboard strake of the shell plating to be used as a double bottom drain in the dry-dock. 133. Drift Angle: As a vessel turns in a circle its bow lies inside of the path which its Center of Gravity traverses and its stern lies outside of this path. The angle intercepted by the centerline of the vessel and a tangent to the turning circle at the Center of Gravity is called the drift angle 134. Dog:A small bent metal fitting used to hold doors, hatch covers, manhole covers, etc., closed. A bent bar of round iron used for holding shapes on bending slab. 135. Donkey Boiler/Engine: A small gas steam or electrical auxiliary engine, set on the deck & used for lifting or auxiliary power. Separate from the main power system of a vessel 136. Doubling plate: A plate fitted outside or inside of and faying against another to give extra strength or stiffness in areas of high stress. Around hatches, stringer strake etc. 137. Draft: (Describe function) The depth to which a vessel sinks which is equal to a specific volume of displacement based on the ship's hull form at that draft and a particular weight based on that volume of displacement. 138. Draft marks: Located at the waterline forward and aft. Draught: The vertical distance of the lowest point of the ship below the surface of the water when she is afloat. Draft Marks: The numbers painted at the bow and stern of a vessel to indicate how much water she draws. These marks are 6 inches high and spaced 12 inches apart vertically. 139. Dressler Coupling: A flexible coupling/union in an unflanged pipeline which allows for repair of the pipeline without special flanged pipe sections and allows expansion and contraction in the pipeline system due to bending moments, flow or thermal activity. page 52 140. Drift pin: A small tapered tool driven through rivet holes and used to draw adjoining plates or bars into alignment with each other. 141. Dry-dock:(Describe Graving & Floating dock, Marine railway, careening) A dock in which a ship's hull may be kept out of water during construction or repair. Three types are used: (1) the graving dock, a basin excavated near a waterway, with a gate to exclude the water after pumping out; (2) the floating dock, a hollow structure of wood or steel, which is sunk to receive the ship to be docked and is pumped out to lift it from the water; (3) the marine railway, a cradle of wood or steel on which the ship may be hauled out of water along inclined tracks leading up the bank of waterway. Massachusetts Maritime Academy

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142. Dutchman: between members.

Any piece used to connect two or more pieces, or a piece to fill in a gap

143. Erect: To hoist into place and bolt up on the ways fabricated and assembled parts of a ship's hull, preparatory to riveting or welding. 144. Escape trunk: A vertical trunk usually located at the aft end of the shaft alley to permit engine room personnel to escape when the shaft alley watertight door is closed. 145. Even keel:A ship is said to be an even keel when the keel is level or parallel to the surface of the water and the hull is not listed or tipped sideways. 146. Expansion trunk: Upper portion of tank on an oil tanker, used to allow for the expansion of oil when temperature rises. 147. Eyebrow: A plate shaped around the top of an opening to prevent drainage from entering the opening. 148. Fabricate: To process hull material in the ships prior to assembly or erection. In hull work fabrication consists in shearing, shaping, punching, drilling, countersinking, scarfing, rabbeting, beveling, etc. 149. Facing Plate: A plate fitted perpendicularly to the web and fastened to the flanges at one end of a frame, stiffener, or girder to compensate for the continuous plating attached to the flanges at the other edge. In welded construction a narrow flat plate fitted to the free edge of a flat bar stiffener 150. Fair:(fair-up) To correct or fair up a ship's lines on mold loft floor; to assemble the parts of a ship so that they will be fair, i.e., without kinks, bumps, or waves; to bring the rivet holes into alignment. 151. Fairwater: Plating fitted in the shape of a frustum of a cone, around the ends of shaft tubes and struts to prevent an abrupt change in the stream lines. Also any casting fitted to the hull for the purpose of preserving a smooth flow of water 152. Faying surface: The surface between two adjoining parts or the touching surfaces. 153. Fidley hatch: 154. Fillet:

Hatch around smokestack and uptake, for ventilation of boiler room.

The rounded edge of a rolled steel angle or bar.

155. Fixed light:

Circular window with fixed glass in side of ship, door, skylight cover, etc.

156. Flange: Portion of a plate or shape at or nearly at right angles to main portion; to flange is to bend over to form such an angle. page 32-33 and pages 47-52 157. Flange, spectacle: A swinging blank between two flanges which can be rotated to an open or closed position in a pipeline system. page 51 Massachusetts Maritime Academy

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158. Floodable length: The length of a vessel around a given point that when flooded will immerse the vessel to the margin line. 159. Floor: (Describe Open, Close, and Solid Floors) A plate placed vertically in the bottom of a ship, usually on every frame and running athwartship from bilge to bilge. page 64-65 160. Floor plate:

Vertical plate in bottom (see floor).

161. Flounder plate: A triangular plate fitter to the topping lift to assist in topping and making fast the boom. 162. Forecastle:

The forward upper portion of the hull, usually used for crew's quarters.

163. Forefoot: The part of the stem that curves aft to meet the keel. page 79 164. Forepeak: A large compartment, or tank, at the bow in the lower part of the ship forward of the collision bulkhead 165. Forging: A piece of metal hammered, bent, or pressed to shape while white-hot. 166. Foundations, main:

Supports for boilers and engines.

167. Foundations, auxiliary: condensers, heaters, etc. 168. Frame:

Supports for small machinery such as winches and also for

One of the ribs forming the skeleton of a ship.

169. Frame, panting:A frame of increased scantlings located in the bow or stern area to provide additional strength to resist panting stresses. 170. Frame, cant: Frames which are located in the stern to support the overhang of the stern which are not square to the center line of the vessel. A frame not square to the center line, usually at the counter of the vessel. page 81 171. Frame, Boss:

Hull frame that is bent for clearing propeller shaft tube.

172. Frame, reverse: An angle bar or other shape riveted to the inner edge of a transverse frame for reinforcement. page 70 173. Frame spacing: The fore-and-aft distance between heel and heel of adjacent transverse frames along the center line. Frames are more closely spaced in the forward and aft part of the vessel for added strength. 174. Frame, split: A channel or Z bar frame split at the bilge so that one flange may connect to the shell plating, and the other to the tank top. 175. Frame stations: Transverse planes which are parallel to base line divide the ship into equal parts on the lines drawings. The appearance of the various frame stations is depicted on the Body Massachusetts Maritime Academy

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Plan. 176. Frame, stern: Last casting or forging attached to the after end of the keel to form the ship's stern, includes rudderpost, propeller post and aperture for the propeller. 177. Frame, transverse:

The athwartship members forming the rib's of the ship.

178. Frame, web: Heavy side or continuous frame, made with web plate between its members. A built-up member consisting of a web plate, to the edges of which are attached single or double bars if riveted, or a face plate, if welded. page 60-61 179. Freeboard: 28

The distance from the water line to the top of the weather deck at side. page

180. Freeing port: A large opening in the bulwark just above the deck so that when seas break over the deck, the ship can clear itself of the sea water quickly. Rods or bars are generally fitted across freeing ports to prevent men being washed overboard through these openings. 181. Furnace: Heater or large forge for heating plates or shapes for bending. To furnace is to bend by heating in furnace. 182. Galvanizing: Coating metal parts with zinc for protection from rust. Galvanizing results in approximately a 10% loss in strength for components of equivalent size and should not be used for running rigging applications. 183. Gasket: (Describe materials used) Flexible material used to pack joints in machinery, piping, doors, hatches, etc., to prevent leakage of liquids or gasses. 184. Girder: A continuous member running in fore-and-aft direction under the deck for the purpose of supporting the deck beams and deck. The girder is generally supported by widely spaced pillars. 185. Girth:

Distance around a vessel's frame from gunwale to gunwale.

186. Grating: A structure built out of wooden strips or metal bars, to form a walkway above a deck or opening without interference with light, drainage, or ventilation. 187. Groundways: Timbers fixed to the ground, under the hull on each side of the keel, on which ship slides during launching. page 80-83 188. Gudgeons:

Bosses on sternpost drilled for pins (pintles) for rudder to swing on. page 75

189. Gunwale bar: Angle bar that connects deck stringer plate and shell plates at weather deck. 190. Gusset plate:

Triangular plate that connects members or braces. page 70

191. Hatchway: Opening in deck for passage of cargo, etc. usually formed by a raised hatch coaming and fitted with a watertight cover. Massachusetts Maritime Academy

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192. Hawse pipe: Casting extending through deck and side of ship for passage of anchor chain, and for stowage of anchor in most cases. page 83 193. Header: A member added for local strength which is not parallel to the main strength members of the vessel. Usually used to deliver the load from some strength member, which has been cut, to other strength members in the area. 194. Head reach: The distance that a vessel travels from the time that the order to put the engines full astern until the vessel is dead in the water. 195. Heeling: The inclination of the vessel due to external forces. 196. Hold:

The spaces below deck allotted for the stowage of cargo.

197. Horning: Setting the frames of a vessel square to the keel after proper inclination to the vertical due to the declivity of the keel has been given 198. Horseshoe plate: Small horse shoe-shaped plate around rudder stock on shell of ship, for the purpose of preventing water backing up into the rudder trunk. page 75 199. Intercostal: Made in separate parts between frames, beams, etc., the opposite of "continuous." page 64 200. Inverted angle: An angle with the toe welded to a plate thus, in effect, in conjunction with a portion of the plate adjacent to the toe, forming a channel. page 70. 201. Joggle:

To offset a plate or shape to save the use of liners. Fig. 80, page 150

202. Joiner: Light finish work (i.e.) covers, deck ladders light metal bulkheads such as those used in cabins and staterooms. 203. Keel: The principal fore-and-aft member of a ship's frame, which runs along the bottom and connects the stern and stem and to which are attached the frames of the ship. It is the backbone of the ship's frame. page 64 204. Keel, bar: A keel that protrudes through the bottom as in lifeboat construction. 205. Keel blocks:

Heavy blocks on which ship rests during construction.

206. Keel, center vertical: A continuous longitudinal girder in the vertical axis on the center line above the keel strake used in cellular double bottom construction. Row of vertical plates extending along center of flat plate keel. Sometimes called center keelson. page 64 207. Keel, docking: Keel on either side, and in the plane of the center keel, used to distribute the weight in the dry dock in the case of large vessels. 208. Keel, flat plate: A fore-and-aft row of flat plates end to end on the center line, running along the bottom of the ship from stem to stern, the forward and after plates being dished up into a U shape. page 64 Massachusetts Maritime Academy

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209. Keelson, side: Fore-and-aft member placed on each side of, and similarly to, the center vertical keel. page 64 210. Kick: The distance a ship moves sidewise from the original course away from the direction of the turn after the rudder is first put over. The term is also applied to the swirl of water toward the inside of the turn when the rudder is put over. page 84 211. King post:A stub mast or a heavy vertical post, outboard from center line, to carry cargo booms; also called Samson post. 212. Knuckle: A sharp bend in a plate or shape. 213. Knuckle plate: A plate bent to form a knuckle. 214. Kort Nozzle: A hollow tube around the propeller used to improve thrust. 215. Lap: A joint in which one part overlaps the other the use of a butt strap being thus avoided. Fig. 71), page 149, Fig 80, page 150 216. Laminated plate: A rolled piece of steel which looks more sandwich like than solid when viewed sideways. Sheet steel in laminated with vinyl today for interior joiner work. 217. Launching: The operation of placing the hull in the water by allowing it to slide down the launching ways. During launching, the weight of the hull is borne by the cradle and sliding ways, which are temporarily attached to the hull and slide with it down the ground ways. 218. Laying off:

Marking plates, shapes, etc., for fabrication.

219. Length between perpendiculars: The length of a ship measured from the forward perpendicular to the after perpendicular used for calculations of the ship's hydrostatic properties. 220. Length overall: The length of a ship measured from the forward most point of the stem to the after most point of the stern used for maneuvering the vessel. 221. Lift: To "lift" a template is to make it from measurements taken from the job. 222. Lightening hole:

A large hole cut in a structural member to reduce its weight. page 64

223. Limber hole: A hole of a few inches in diameter cut in a floor plate to allow water to drain through it near the bottom. page 64 224. Liner: (Describe plating systems and materials) A flat or tapered strip placed under a plate or shape to bring it in line with another part that it overlaps; a filler. Fig. 30, page 150 225. List: (Describe causes) The inclination of the vessel due to internal forces. The two causes of list are off center weight and negative GM (Loll). 226. Load water line: Line of surface of water on a ship when loaded to maximum allowance in salt water in the summertime. Massachusetts Maritime Academy

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227. Longitudinal: A fore-and-aft structural member running parallel or nearly parallel to the center vertical keel, along the inner bottom, shell, or deck. page 64 228. Manhole: A round or oval-shaped hole cut in a ship's divisional plating, large enough for a man to pass through. 229. Manifold: A box casting containing several valves, to which pipe lines are led from various compartments and pumps on a ship, so as to allow any tank to be connected to one or more pumps. page 111 230. Margin:

Usually a plate or a shape attached to the outer edge of the double bottom.

231. Margin angle: Angle bar connecting margin plate to shell. 232. Margin line: Imaginary fore and aft line used in floodable length <3 calculations relating to the subdivision of the vessel. It is located three inches below the upper surface of the bulkhead deck at the vessel's side. 233. Margin plate: Any one of the outer row of plates of the inner bottom, connecting with the shell plating at the bilge. 234. Mast:

A large, long spar, placed nearly vertical on the center line of a ship.

235. Mold: A light pattern of a part of a ship. Usually made of thin wood or paper. Also called a template. Fig. 72, page 142 236. Mold loft: Usually the second floor of a building with a large smooth floor for laying down the lines of a vessel to actual size and making templates from them for the structural work entering into a hull. Fig. 72, page 142 237. Mooring ring: A round or oval casting inserted in the bulwark plating of a ship, through which the mooring lines, or hawsers, are passed. 238. Notches: Any discontinuity in a structure such as an opening in the hull, plating or a weld. 239. Oiltight: Riveted, caulked, or welded to prevent oil leakage. 240. Overhang:Portion of the hull over and unsupported by the water. 241. Oxter plate: plate.

A bent shell plate that fits around upper part of sternpost; also called tuck

242. Packing: (Describe function and materials) Material put between plates or shaped to make them watertight. Wooden blocks and wedges supporting ship on sliding ways. 243. Paravane: An object shaped like a small airplane. When two paravanes are attached to steel cables are 'Lowered into position on a paravane skeg, one port and one starboard, they trail out at 45° angles. When anchor cable, of a mine, strikes the paravane, the mine travels to the paravane where it is cut loose. Used to day to tow underwater instruments and deploy fishing gear. Massachusetts Maritime Academy

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244. Paravane, skeg:A finlike protuberance at the bottom of the stem which allows the paravane crotch to ride at the lowest part of the stem. page 75 245. Permissible Length: The maximum length allowed between watertight bulkheads. 246. Permeability of a Vessel: The volume of a vessel's hull which could be occupied by water if the vessel were flooded. Thus a 60% permeability would allow for more water to be -added to the vessel than 40% permeability. 247. Perpendicular, after: A line perpendicular to the base line, intersecting the after edge of the sternpost at the desired water line. 248. Perpendicular, forward: A line perpendicular to the base line, intersecting the forward edge of the stem at the designed water line. 249. Pillar: Vertical member or column giving support to a deck girder. Also called stanchion. Circular hollow pipe or hollow plate provide the most strength with the least amount of weight. 250. Pintles:

The pins or bolts that hinge the rudder to the gudgeons on the sternpost. page 75

251. Pivot Point: The point which scribes the path of the turning circle and about which the ship turns when the rudder is put over. The pivot point is located approximately one-sixth of the length of the ship from the bow. The pivot point will be located slightly aft of 1/4 - 1/3 the vessels length when trimmed by the stern and slightly forward when trimmed by the head. As the speed of the vessel increases the pivot point will move forward. When backing to pivot point is located aft. The pivot point can be located on a diagram of the turning circle by constructing a perpendicular from the center of the circle to the centerline of the ship. page 84 252. Planking: Wood covering for decks, etc. 253. Plans, Body: An end view showing the curves of the sides of the ship's transverse lines. Frame stations appear as curves lines. page 30 254. Plans, capacity: A general plan of the board profile of the vessel which provides data relating to the cargo capacity of each cargo space including measurements, cubic capacity and deck stresses as well as a deadweight scale which includes, mean draft, displacement, deadweight, TPI, MTI. 255. Plans, dry-docking: (Docking Plan) A plan used by dry-docking officials to determine the position of the blocks prior to entering the dock. It consists of a longitudinal section with transverse bulkheads, engine room and boiler space, an sea connections. At various point cross sections are shown giving the form of the bottom, rise of the floors, and fullness of the ends. 256. Plans, firefighting: A general arrangement plan detailing the location of all required firefighting equipment fitted aboard the vessel. 257. Plans, general arrangement: and spaces aboard the vessel. Massachusetts Maritime Academy

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258. Plans, Half-breadth: A plan or top view of half of the ship divided longitudinally drawn for the port side only, showing the water line planes as curved lines. page 30 259. Plans, lines: Plan which divides the ship into three planes which detail the appearance and form of the entire ship's hull in these three plans (Body, Half-breadth, Profile). 260. Plans, midship section: A plan showing a cross section of the ship through the middle, or amidships. This plan shows sizes of frames, beams, brackets, etc., and thicknesses of plating. Fig 69A pages 120-121 261. Plans, mooring arrangement: k general plan detailing the location of the vessels mooring equipment (ground tackle) including the proper lead for each mooring line and the rated capacity of each piece of equipment. 262. Plans, piping arrangement: A series of general plans detailing the arrangement and location of tire vessel’s piping systems. 263. Plans, Sheer or Profile: Side elevation or fore-and-aft centerline section of a ship's form or structure showing the contour of the stem and stern of the vessel in which the buttocks lines appear as curved lines. page 30 364. Plans, shell expansion: 265. Platen:

A plan showing details of all plates of the shell.

Skids on which structural parts are assembled.

266. Platform: A flat deck without camber or sheer. 267. Plating, butt: The joint formed when two parts are placed edge to edge; the end joint between two plates. 268. Plating, seam: Fore-and-aft joint of shell plating, deck and tank top plating, or lengthwise side joint of any plating. 269. Plating, flush: Most common type of welded hull construction where individual plates are welded together at the seams and butts. 270. Plimsoll mark: A mark stenciled in and painted on the side of a vessel, designating the depth to which the ship may be loaded is Summer, the assigning body, and the service for which the vessel is intended. Fig. 48 page 80 271. Poppets: Pieces of timber which are fixed perpendicularly between the ship's bottom and the bilgeways at the foremost and aftermost parts of the ship, to support her launching. ] page 80 279. Propeller post: Forward post of stern frame, through which propeller shaft passes. page 75 272. Quadrant: A casting, forging, or built-up frame, on the rudder head, to which the steering chains are attached. Massachusetts Maritime Academy

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273. Rabbet: A depression or offset of parallel depth designed to take some other adjoining part, as for example, the rabbet in the stem to take the shell plating. 274. Reaming: Enlarging a rivet hole by means of a revolving cylindrical, slightly tapered tool with cutting edges running along its sides. 275. Ribband: A fore-and-aft wooden strip or heavy batten used to support the transverse frames temporarily after erection and to keep them in a fair line; also, any similar batten for fairing a ship's structure. 276. Rider Plate: A horizontal fore & aft plate riveted to the top angles of a centerline keelson running above the floors. Bed plates set on top of the center keelson, if fitted for pillars to stand on. page 64 277. Rigging: Ropes, wire ropes, lashings, etc., used to support masts, spars, booms, etc., and also for the handling and placing onboard the ship of its cargo. 278. Rivet: (Draw and name parts, define pitch & gage) A short, round metal connection used to fasten two or more members together by clinching after heating red-hot. page 34-35 279. Rose box: A galvanized iron box with the sides perforated by small holes, the combined area of which equals at least twice the area of the bilge suction pipe. The object is to collect bilge water for pumping out and to prevent refuse from clogging the pumps. 280. Rough bolt:

To bolt a plate or frame to ship until it can be faired for reaming.

281. Rudder, balanced: A rudder Which places the rudder stock about 1/4 of the length from the leading edge of the rudder and balanced for a rudder angle of 150. page 76-77, Fig. 110, page 210 282. Rudder, semi-balanced: The type of rudder with most of the rudder is hinged on the body post by the pintles and gudgeons, but a small portion of the rudder projects forward and under the rudder post. page 76-77, Fig. 111 page 211 283. Rudder, unbalanced: The type of rudder which is hinged or attached to the rudder post of the stern frame and pivots on the pintal and gudgeons. page 76-77, Fig. 108 & 109, page 209 284. Rudder, contraguide: The type of rudder which is designed to receive a forward push from the rotation of the water in the propeller race which is lost energy unless the contraguides are fitted. It attempts to remove some of the steering bias as a result of the additional acceleration of the race. page 76-77, Fig. 110, page 210, Fig. 112, page 212 285. Rudder lug: A projection cast or fitted to the forward edge of the rudder frame for the purpose of taking the pintle. 286. Rudderpost:

After post of stern frame to which rudder is hung. Also called sternpost.

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rudder. 288. Rudder stop: of the rudder.

Lug on stern frame or a stanchion at each side of quadrant, to limit the swing

289. Scantlings: The dimensions or sizes of the frames, girders, etc. A FULL-SCANTLING VESSEL: The position of the load line on seagoing vessels depends on the strength of the hull, provided that a reasonable margin of buoyancy (reserve buoyancy) is left. It is, therefore, unnecessary to increase the scantlings of the vessel when this margin has been reached as freeboard can not be reduced beyond this point. A full scantling vessel is one in which the scantlings correspond to the above mentioned margin of buoyancy and in which full strength of the ship's structure is maintained up to the upper most continuous deck of the vessel. Classification Societies require, according to the depth of the vessel, that 1, 2, or 3 full decks should be provided for, if the vessel is to be accepted as a full-scantling vessel. 290. Scarf: A connection made between two pieces by tapering their ends so that they will mortise together in a joint of the same breadth and depth as the pieces connected. It is used on bar keels, stem and stern frames, and other parts. 291. Scupper: Drains from weather decks to carry off accumulated sea and rain water. 292. Scuttle: A small opening, usually circular in shape, and generally fitted in decks to provide access or to serve as a manhole or opening for stowing fuel, water, and small stores. 293. Sea chest: A casting fitted to shell of a vessel for the purpose of supplying water from the sea to the condenser and pumps. 294. Seam, strap:

Strap connecting plates to form a flush seam. Fig. 79, page 149

295. Serrated member: A rolled section in which the web has been cut short and long. The longer web pieces are welded to the plating, leaving the shorter section clear of plating for drainage. Common on stringers. 296. Shaft alley (shaft tunnel): A watertight casing covering propeller shaft, large enough to walk in, extending from engine room to afterpeak bulkhead, to provide access and protection to shaft in way of after cargo holds. 297. Shape: Bar of constant cross section throughout its entire length, such as a channel, T bar, or angle bar. pages 32-33 298. Shear:

A stress that tends to cause the adjacent parts of a body to slide over each other.

299. Shear Line: 300. Shears:

Line to shear or cut to.

Large machine for cutting plates and shapes.

301. Sheer: Fore-and-aft curvature of a deck which provides additional reserve buoyancy forward and aft and provides for better drainage of the decks. page 28 Massachusetts Maritime Academy

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302. Shell landings: Points on the frames showing where the edges of shell plates come. 303. Shell plating: The plates forming the outer skin of the hull. Plate is measured by weight in which l' x l' area is employed each 1/4" of thickness is approximately 10 pounds. Thus 30 lbs. plate is 3/4" thick. 304. Shore & Tom: (Describe cutting, wedges and installing) Shore up and tom down braces are cut about 1/2" shorter to allow wedges to be driven in. 305. Shroud:

An athwartship guy use to support masts.

306. Skeg: A deep fin like projection on the bottom of a vessel, usually toward the stern, installed to support the lower edge of the rudder, to support the propeller shaft, for strength, to prevent erratic steering in a seaway and damage to the rudder and propeller. page 64 307. Skids:

Timbers on which structural parts are assembled.

308. Skylight: An opening in a deck to give light and air to the compartment below it usually fitted with hinged covers having fixed lights in them. 309. Sounding pipe: Pipe in oil or water tank used to measure depth of liquid in tank. Striker plate is located at the foot of the sounding tube. 310. Spar:

A long, round, wooden timber used to carry rigging.

311. Stability: Tendency of a ship to return to her original position when inclined away from that position. 312. Stanchion:

A pillar or upright post; a vertical rail post.

313. Staple angle:

A piece of angle bent in the shape of a staple or other irregular shapes.

314. Stapling: Collars, forged of angle bars, to fit around continuous members passing through bulkheads, for watertightness; now obsolete. 315. Stay:(Describe Forward and Back) A fore and aft guy line. 316. Stem: Forging or casting forming extreme bow of ship, extending from keel to forecastle deck. page 79 317. Sternpost: After part of stern frame to which rudder is attached also called rudderpost. page 64 318. Stern tube:

Tube through stern through which propeller shaft passes.

319. Stiffener: An angle bar, T bar, channel, built-up section, etc., used to stiffen plating of a bulkhead, etc. 320. Stopwater:

Canvas soaked in red lead or other material, fitted between two metal parts

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to make a watertight joint. 321. Storm valve:

A check valve in a pipe opening above water line on a ship.

322. Strain:

Alteration in shape or dimensions resulting from stress. pp. 15

323. Strake:

A course or row of shell or other plating.

324. Strake, bilge:

Course of hull plating at the turn of the bilge.

325. Strake, drop: A strake that is terminated before it reaches the bow or stern. The number of strakes dropped depends on the reduction of girth between the midship section and the ends. page 117 326. Strake, garboard:

The strake of hull plating closest to the keel strake. page 62

327. Strake, margin: The strake of plating at the turn of the bilge which connects the inner bottom with the outer hull. page 64 328. Strake, stealer: (Stealer Plate) A plate or strake extending into an adjoining strake in the case of a. drop strake. Stealer plates are located in the bow and stern, where the narrowing girth compels a reduction in the number of strakes. page 117 329. Strake, sheer: Top full course of shell plates at strength deck level. Page 62 330. Strake, stringer: the strake of deck plating which provides a means of watertight connection for the main deck and hull, deck beams and frames and provides a gutter for water run off if a doubler is fitted. 331. Strake, through: 332. Stress:

A strake of hull plating which runs the entire length of the vessel.

Force per unit area.

333. Stress, compression: The stress which results from two forces acting in opposite directions on the same line tending to push a material together. 334. Stress, hogging: Straining of the ship that tends to make the end portions lower than the mid-section. Weight concentrations in the ends of the vessel. 335. Stress. Panting:The in-and.-out vibrations of the frames and shell plating due to variation of wave pressure most noticeable in the bow and stern. 336. Stress, racking: Straining of a ship that tends to make the decks and bottoms no longer square with the sides. 337. Stress, sagging:Straining of the ship that tends to make the middle portion lower than the bow and stern. Weight concentrations in the mid-section of the vessel. 338. Stress, shear:

Stress resulting from two forces acting in opposite directions along parallel

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lines. To shear as a bolt. Bending moments must exist in order to generate these stresses. 339. Stress, tension: The stress which results from two forces acting in opposite directions on the same line tending to pull a material apart. 340. Stringer: A fore-and-aft member used to give longitudinal strength to shell plating. According to location, stringers are called hold stringers, bilge stringers, side stringers, etc. 341. Strongback: (Riveting & securing) A portable supporting girder for hatch covers-. A rig used to straighten bent plates. A bar for locking cargo openings. A central girder used to support covers of canvas, wood or metal. 342. Strum box: The enlarged terminal on the suction end of a pipe and forming a strainer that prevents the entrance of materials likely to block the suction line. 343. Strut: propeller.

Outboard support for propeller tail shaft, used on ships with more than one

344. Superstructure: A structure extending all the way across the ship, built immediately above the uppermost complete deck. 345. Swash plate:

Baffle plate in tank to prevent excessive swashing.

346. Sweat batten: Wooden planks which prevent the cargo from coming into contact with the sides of the vessel which may be moist as a result of the difference in the temperature of the hull in contact with the water outside and the cargo hatch. 347. Tail shaft: Short section of propeller shaft extending through stern tube and carrying propeller. 348. Tank, ballast: A tank which is designed or designated to carry ballast for the purpose of stability or trim of the vessel. 349. Tank, deep: A tank which is deep and is designed to carry either liquid cargo or both liquid and dry cargo. if the deep tank is intended for the carriage of liquids only the structural members will be inside the tank. 350. Tank, double bottom: A tank which is located between the inner and outer bottoms which may contain fuel oil, water or ballast 351. Tank, flume: An anti-roll tank which uses baffle plates to delay the passage of water through the tank reducing rolling by having water on the low side. The two basic types are either the "U" tube or over and under type. 352. 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 and size of laps is indicated. Common types are made of paper or thin boards. Massachusetts Maritime Academy

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353. Thrust bearing: Bearing on propeller line shaft, which relieves the engine from the driving force of the propeller and transfers this force to the structure of the ship. 354. Tie plank: The fastening holding the ship from sliding down the ways; also called sole piece. 355. Tie plate: A single fore-and-aft course of plating attached to deck beams under wood deck to give extra strength. 356. Tiller:

Arm attached to rudderhead for operating rudder.

357. Ton, displacement: The unit of displacement expressed in tons which is equal to the volume of liquid in which the vessel is afloat. The weight of water displaced by a vessel afloat which is equal to the weight of the vessel. In salt water one (l) long ton is equal to 35 cubic feet of volume and in fresh water one long ton is equal to 36 cubic feet of volume. The vessel's displacement at any condition of loading is equal to the sum of the light displacement plus the deadweight. 358. Tonnage, light displacement: The weight of the vessel in tons when unloaded or the weight of the ship itself. It includes the hull and all permanent fittings, engines and boilers, shafting and propellers, water in boilers, condensers, and pipes, feed water, and permanent ballast. 359. Tonnage, loaded displacement: The weight of the vessel in tons when it floats at its loaded draft or when it has all its weights on board. 360. Tonnage, deadweight: The vessel's lifting capacity or the number of long tons (2240lbs.) that a vessel will lift when loaded in salt water to her Summer Freeboard Marks. It is the numerical difference in long tons (2240lbs.) between the loaded displacement of the vessel in salt water and the light displacement of the vessel. Deadweight tonnage is the best indicator of the cargo carrying capacity of the vessel in long tons because the ship's officer knows the quantity of ballast and consumables aboard the vessel at any given time. Sometimes also referred to as deadweight tonnage. Deadweight capacity includes: Crew, passengers, luggage, provisions and stores, fresh water in storage tanks, service tanks, and pipage, furniture, bedding, napery, cooking utensils and apparatus, crockery, plate, and cutlery, mails and specie, parcels, cargo, coal in bunkers and on the fire grates, fuel oil in tanks and piping, lubrication oils in tanks and piping, fresh and salt water ballast in tanks and piping, spare gear, bilge water and ashes. 361. Tonnage, equipment:Equipment tonnage is a type of measurement tonnage since one equipment ton is equal to various units of space (cubic volume). It differs from Gross tonnage in that there are no exempted spaces, and therefore, a truer criterion of the internal size or volume of the vessel. Equipment tonnage is used by the American Bureau of Shipping (Classification Society) as a basis for determining the scantlings (size and strength) of such ground tackle as anchors and cables, mooring wires and winches. 262. Tonnage, gross: A gross ton is a unit of capacity of 100 cubic feet to the ton (2.83 cubic meters) which is used for ascertaining the legal or register tonnage of the vessel. Also called gross register or register tonnage. Used for regulatory purposes. Gross tonnage or gross register tonnage may be defined as the total internal volume of a vessel in units of 100 cu. feet to the ton, less the volume of certain spaces which are EXEMPTED to encourage the use of spaces devoted to safety of the ship or the comfort of the crew and certain spaces because they are not 11 closedMassachusetts Maritime Academy

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in". The actual cubical contents of any space is measured in accordance with prescribed methods and formulae as originated by Moorsom, which are incorporated in the measurement rules of the leading maritime nations. Spaces on or above the upper deck which are exempted: Companion ways, galley, machinery spaces, skylights, public water closets, wheelhouse, air and light space, passenger spaces above the first deck which is not a deck to the hull, open superstructures, open shelter decks. The lack of uniformity in gross tonnage measurement for vessels of various nations results from not only various methods of measurement, but also from the number of spaces which are exempted from measurement. The inception of Suez and Panama Canal Tonnages attempts to equate all vessels to standard tonnage rules based on the Moorsom principles for the purpose of canal tolls. Since some spaces are exempted it therefore follows that gross tonnage does not represent the true internal capacity of the vessel. 363. Tonnage, net: Net tonnage may be defined as gross tonnage less the volume of certain specified DEDUCTED spaces which are not available for the carriage of cargo or the accommodation of passengers or spaces intended for revenue earning. It is the Net Register Tonnage upon which taxes are levied. Spaces which are deducted from gross tonnage are:crew accommodations, private water closets, Master's cabin, anchor gear, chart room and radio room, boatswain's storerooms, propelling machinery spaces. Net tonnage deducted spaces are easily identified by the words "Certified" is cut into the main beam when entering the space. 364. Tonnage Opening: tonnage rating.

Openings in the shelter deck bulkheads for purpose of economy in

365. Transfer: The distance gained by b vessel to the right or left of the original track from the time the helm is put hard over until the ship has turned to its new heading. page 74 366. Transom: The aftermost transverse frame. 367. Trim: To shift ballast to make a ship change its position in the water. The trim is the excess of draught forward or aft. 368. Trunk: Steel casing passing through deck and forming an enclosure for ladders or cargo hatches. 369. Tumble

home:

Slant inboard of a ship's side above the bilge. page 28

370. Uptake: A sheet-metal conduit connecting the boiler smokebox with the base of the smokestack. It conveys the smoke and hot gases from the boiler to the stack. 371. Ventilator:A device for furnishing fresh air to compartments below deck. 372. Warping bridge: docking bridge.

Bridge at after end of hull, used while docking a ship; also called

373. Water line: The line of the water's edge when the ship is afloat technically, the intersection of any horizontal plane with the molded form of the ship. 374. Watertight:

So constructed as to prevent the passage of water.

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375. Watertight flat: Short section of watertight deck, forming a step in a bulkhead or the top of a watertight compartment or water tank. 376. Waterways: gutter. 377. Ways:

A narrow passage along the edge of the deck for the drainage of the deck. A

Timbers, etc., on which a ship is built or launched.

378. Web:The vertical portion of a beam, the athwartship portion of a frame, etc. page 31-32 379. Weeping: Very slow issuance of water through a seam in a ship's structure or from a containing vessel insufficient in quantity to produce a stream. 380. Welding: (Indicate types of welding) Making a joint of two metal parts by fusing the metal in between them or by forging together at welding heat. 381. Well:Space in bottom of a ship to which bilge water runs so that it may be pumped out. 382. Whaler: section etc.

Any steel or wooden member used for temporarily bracing a bulkhead, deck

383. Windlass: The machine used to hoist the anchors positioned in the horizontal axis. 384. Wind sail: A portable canvas device use to divert air into a space. 385. Wind scoop:

A device used to divert air into a compartment of a ship through an air port.

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