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STEM /BOWForward part of a ship
STERNAft part o f a ship
PORT SIDEThe left-hand side of a ship when facing the front or forward end
STARBOARD SIDEThe right-hand side of a ship when facing the front or forward end. The starboard
side of a ship during darkness is indicated by a green light.
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INBOARDA term to signify in the ship
OUTBOARDA term to signify out of the ship
LENGTH OVERALL (L.O.A)
Distance from extreme ford to extreme aft end
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t
b
dLWL
LWL
FPAP
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LENGTH OF WATER LINE (L.W.L)Is the distance of water line from stem to stern
FORWARD PERPENDICULAR (F.P)Perpendicular at intersection of LWL and stem
AFT PERPENDICULAR (A.P)
Perpendicular at intersection of LWL and rudder postor
Perpendicular through C.L of rudder stock if no rudder POST
Where LWL is load water line
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LENGTH BETWEEN PERPENDICULAR (L.B.P)
Length between F.P and A.P
SUMMER LOAD WATERLINEThe deepest waterline to which the ship is allowed to load
Design draft
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MIDSHIP
Is the section midway between perpendiculars
MOULDED BREADTH
Breadth measured amid ship below the weather deck
BREDTH EXTREMEMoulded breadth + shell plating + fender
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MOULDED DRAFT (T)Vertical distance from top of the flat keel to design waterline
MOULDED DEPTH (D)Vertical distance from top of flat keel to underside of the Uppermost continuous
deck plating
FREEBOARDIs the difference between depth and draft
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TRIMSinkage of ship in longitudinal direction
HEEL
Sinkage of the ship in transverse direction
LISTPermanent heel
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RISE OF FLOORThe distance above the keel that a tangent to the bottom Cuts the line of
maximum beam midship
TUMBLE HOMETendency of a section to fall in towards the middle line plane From the vertical as it
approaches deck side
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DECK CAMBER
Is the curve applied to the deck transversely
FLARETendency of a section to fall out of the middle line plane from
the vertical as it approaches deck side
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SHEERTendency of a deck to rise above the horizontal in profile
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RAKE
Departure from vertical of any profile
Rake A departure from the vertical or horizontal of any profile, defined by a rake angle or
by the distance between the profile line and a reference line at a convenient point. Rakeof stem, for example, can be expressed as the angle between the stem bar and the
forward perpendicular. Ships designed so that the keel is not parallel to the baseline and
DWL when floating at their designed drafts are said to have raked keels, or to have drag
by the keel.
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ENTRANCEForward part of the ship having varying cross section
RUNAft part of the ship having varying cross section
PARALLEL MIDDLE BODYMiddle part of the ship having constant cross section
DISPLACEMENTWeight of the ship in the floating condition
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TERMINOLOGY
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BODY PLANA plan consisting of two half transverse elevations or end views of a ship, both
having a common vertical center line, so that the right-hand side represents the shipas seen from ahead, and the left-hand side as seen from astern.
BUTTOCK LINESThe curves shown by taking vertical longitudinal sections of the after part of a ship's
hull parallel to the ship's keel. Similar curves in forward part of hull are "bow lines".
HALF-BREADTH PLANA plan or top view of one-half of a ship divided by the middle vertical plane.
GUNWALEA term applied to the line where a weather deck stringer intersects the shell.
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APPENDAGES Structures extending beyond the main hull. Theyinclude items like shafting, rudder, bossing
ASTERN A backward movement of a vessel
ATHWARTSHIP Across the ship, at right angles to the fore-and-aftcenterline
BEAM The width of a ship. Also called breadth.
BILGE KEELA long longitudinal fin fitted on the curved of a ship
at the turn of the bilge to reduce rolling
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BILGE A recess area fitted at the curved section betweenthe bottom and the side into which water drains fromholds or other spaces
BILGE BRACKET A vertical transverse flat plate welded to the tank topor margin plate and to the frame in the area of the
bilge.
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BOW THRUSTERS A propeller at the bow of the ship, used during
maneuvering to provide transverse thrust
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BRIDGE, NAVIGATING The command post of a ship.
BREASTHOOK A triangular plate bracket joining port and starboardside stringers at the stem.
BULKHEAD
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BULKHEADVertical partition walls which separates the interior of
a ship into compartments or rooms
BULKHEAD DECK The uppermost deck to which the transversewatertight bulkheads are carried
BULKHEAD, AFTERPEAK First main transverse bulkhead forward of thesternpost
BULKHEAD,
COLLISION ORFOREPEAK
The foremost main transverse watertight bulkhead
designed to keep water out of the forward hold in
case of bow collision damage
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CAPSTAN A stump with a vertical axis used for handlingmooring and other lines
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CENTER GIRDER A vertical plate on the ship's centerline between theflat keel and inner bottom extending the length of
the ship. Also called center vertical keel, CVK. Or
center keelson.
CHAFING PLATE Bent plate for minimizing chafing of ropes
CHAIN LOCKER A compartment for the stowage of anchor chain
CLASSIFICATIONSOCIETY Independent and reputable organizations whichverifies and inspects vessels for seaworthiness. As
technical experts, they serve to provide the necessary
basis for adjusting insurance rates for the vessel
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CHOCK
A heavy smooth-
surfaced fitting usually
located near the edge of
the weather deckthrough which wire ropes
or fiber hawsers may be
led, usually to piers
COAMING, HATCH The vertical plating bounding a hatch for the purposeof stiffening the edges of the opening and resisting
water entry
CO
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DAVIT A crane arm for handling lifeboats, stores, etc.
COFFERDAM Narrow void space between two bulkheads or floors
DEADWEIGHT It is the difference in weight between a vessel whenit is fully loaded and when it is empty measured by
the water it displaces. Or The amount of a ship's
carrying capacity
DECK A platform in a ship corresponding to a floor in abuilding
DECK, WEATHER Uppermost continuous deck and having no overheadprotection having watertight openings
DECK, FREEBOARD Deck to which freeboard is measured
MAIN DECK
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MAIN DECKThe principal deck of the hull, usually the highest extending from stem to stern and
providing strength to the main hull.
POOPThe structure or raised deck at the after end of a vessel.
SUPERSTRUCTUREA structure built above the uppermost complete deck; a pilot house, bridge, galley
house, etc.
DECK HOUSE Small superstructure on the top deck which containsthe steering wheel and other navigational
instruments.
DISPLACEMENT LIGHT The displacement in tons of the ship complete with all
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DISPLACEMENT, LIGHT The displacement in tons of the ship complete with alloutfit, equipment, and machinery on board but
excluding all fuel, water in tanks, cargo, stores,
passengers, and the crew and their effects. The light
condition displacement includes the lubricating oil for
the machinery and water in the boilers at steaminglevel. Also called light weight.
DISPLACEMENT, LOADED The displacement of a ship when floating at hergreatest allowable draft
DOUBLE BOTTOM Compartments at the bottom of a ship between innerbottom and the shell plating, used for fresh water,ballast water, fuel oil, etc
DRAFT The depth of the ship below the waterline measuredvertically to the lowest part of the hull
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DRY DOCK An enclosed basin used to place a ship on dry landso that all the submerged parts and fittings can be
repaired.
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SLIPWAY a large hill used to launch ships
FATHOM A measure of length equivalent to 6 feet used for
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FATHOM A measure of length, equivalent to 6 feet, used forlengths of anchor chain
FLOOR Vertical transverse plate immediately above thebottom shell plating, often located at every frame,
extending from bilge to bilge.
FRAME Transverse members that make up the rib likeskeleton of a ship
Gangway/
Accommodation ladderA narrow hanging staircase used by persons
entering or leaving a vessel
Embarkation ladder
FORECASTLE The raised part of the forward end of a ship's deck. It
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p p
is used for the storing paints, tackle, deck stores,
tarpaulins, ropes, etc.
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FREEING PORT An opening in the lower portion of a bulwark, whichallows deck water to drain overboard
DRAFT MARKS The numbers which are placed on each side of a ship
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DRAFT MARKS The numbers which are placed on each side of a shipat the bow and stern from the keel
FREEBOARD The distance from the waterline to the upper surface
of the freeboard deck.
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PLIMSOLL MARKA mark painted on the sides of vessel designating the depth to which the vessel
may, under the maritime laws, be loaded in different bodies of water during various
seasons of the year.
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BALLASTAny weight carried solely for the purpose of making the vessel more seaworthy.
Ballast may be either portable or fixed, depending upon the condition of the ship.
Fixed or permanent ballast in the form of sand, concrete, lead, scrap, or pig iron is
usually fitted to overcome an inherent defect in stability or trim due to faulty designor changed character of service. Portable ballast, usually in the form of water
pumped into or out of the bottom, peak, or wing ballast tanks, is utilized to
overcome a temporary defect in stability or trim due to faulty loading, damage, etc.,
and to submerge submarines.
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CARGO HATCHA large opening in
the deck to permit
loading of cargo.
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CASINGS, ENGINE and BOILER ROOMSThe walls or partitions forming trunks above the engine and boiler spaces, providing
air and ventilation and enclosing the uptakes. They extend somewhat above the
weather deck, or superstructure deck if fitted, and are of sufficient size to permit
installation and removal of engines and boilers. Doors are fitted at the several decklevels to permit access to the gratings and ladders.
BULWARK
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BULWARKA 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.
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CHAIN STOPPERA device used to secure the chain cable when riding at anchor, thereby relieving the
strain on the windlass, and also for securing the anchor in the housing position in
the hawse pipe
GYPSYA small auxiliary drum usually fitted on one or both ends of a winch or windlass. The
usual method of hauling in or slacking off on ropes with the aid of a gypsy is to take
one or more turns with the bight of the rope around the drum and to take in or pay
out the slack of the free end.
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HAWSETh h h l l th t f hi ' b i hi h th h h l f th
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The hawse hole also the part of a ship's bow in which the hawse holes for the
anchor chains are located.
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CHART HOUSEA small room adjacent to the bridge for charts and navigating
instruments.
CHINEThe line formed by the intersection of side and bottom in ships having straight or
slightly curved frames.
DEADWEIGHT
The difference between the light displacement and the full load displacement of avessel; the total weight of cargo, fuel, water, stores, passengers, and crew and their
effects that a ship can carry when at her maximum allowable draft.
DOUBLING PLATEAn extra plate secured to the original plating for additional strength
DRAGThe designed excess of draft, aft, over that forward, measured from the designer's
waterline. The drag is constant
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FAIRLEADERA fitting or device used to preserve or to change the direction of a rope, chain, or
wire so that it will be delivered fairly or on a straight lead to a sheave or drum
without the introduction of extensive friction.
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FLOORA plate used vertically in the bottom of a ship running athwart ship from bilge to
bilge usually on every frame to deepen it.
KNOTA unit of speed, one nautical mile/hour
(one nautical mile is 6,080.20 feet)
HATCH BEAMS
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HATCH BEAMSA term applied to the portable beams fitted to the coamings for the purpose of
supporting the hatch covers
KING POSTA strong vertical post used to support a derrick boom
LOUVER
A small opening to permit the passage of air for the purpose of ventilation
MANHOLE
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A round or oval hole cut in decks, tanks, boilers, etc. for the purpose of providing
access.
PAD EYEA fitting having one or more eyes integral with a plate or base to provide ample
means of securing and to distribute the strain over a wide area. Also known as lug
pads, hoisting pads, etc.
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RUDDERA device used in steering or maneuvering a vessel.
SCANTLINGSA term applied to the dimensions of the frames, girders, plating, etc., that enter
into a ship's structure.
SCUPPERSDrains from decks to carry off accumulations of rain water or sea water The
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Drains from decks to carry off accumulations of rain water or sea water. The
scuppers are placed in the gutters or waterways on open decks and in corners of
enclosed decks, and connect to pipes leading overboard.
SCUTTLE
A small opening, usually circular in shape and generally fitted in decks to provideaccess. Often termed escape scuttles, and when fitted with means whereby the
covers can be removed quickly to permit exit, are called quick acting scuttles.
SEA CHEST
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SEA CHESTAn arrangement for supplying sea water to condensers and pumps. It is a cast
fitting or a built-up structure located below the waterline of the vessel and having
means for attachment of the piping. Suction sea chests are fitted with strainers or
gratings.
SHEER STRAKEThe topmost continuous strake of the shell plating, usually made thicker than theside plating below it.
Shaft Bracket
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Shaft Bracket
The shaft bracket helps to keep the propeller shaft securely aligned
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SKEGThe extreme after part of the keel of a vessel, the portion that supports the rudder
post and stern post.
SKYLIGHTAn erection built on a deck having glass lights in its top and fitted over an opening
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An erection built on a deck, having glass lights in its top and fitted over an opening
in the deck for the purpose of admitting light and air to a compartment below.
SOUNDING PIPEA vertical pipe in an oil or water tank, used to guide a sounding device when
measuring the depth of liquid in the tank. Also called a Sounding Tube.
STANCHIONSShort columns or supports for hand rails. Stanchions are made of pipe, steelshapes, or rods, according to the location and purpose they serve
STERN POSTThe main vertical post in the stern frame upon which the rudder is hung. Also called
the Rudder Post.
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SWASH BULKHEADSLongitudinal or transverse nontight bulkheads fitted in a tank to decrease the
swashing action of the liquid contents. Their function is greatest when the tanks are
partially filled. Without them the unrestricted action of the liquid against the sides of
the tank would be severe. A plate serving this purpose is called a swash plate.
TONNAGE Tonnage is a description of the cargo capacity of a merchant ship. It is avolume measurement and does not directly indicate displacement
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Surge : is the linear longitudinal (front/back) motion
Sway : is the linear lateral (side-to-side) motion
Heave : is the linear vertical (up/down) motion
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Roll : is when the vessel rotates about the longitudinal
(front/back) axis.
Pitch : is when the vessel rotates about the transverse (side-to-side) axis.
Yaw : is when the vessel rotates about the vertical (up-down)
axis.
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SeakeepingThe modern term seakeeping is used to describe all aspects of a ship's performance in
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p g p p p
waves, affected primarily by its motions in six degrees of freedom (see illustration).
Seakeeping issues are diverse, including the motions, accelerations, and structural
loads caused by waves. Some are related to the comfort of passengers and crew, some
to the operation of ship systems, and others to ship and personnel safety. Typical issues
include the incidence of motion sickness, cargo shifting, loss of deck cargo, hull bending
moments due to waves, slamming (water impact loads on sections of the hull), added
powering in waves, and the frequency and severity of water on deck.
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STABILITY
Intact : The vessel is in normal operational configuration. The hull is not breached in anycompartment. The vessel will be expected to meet various stability criteria such as GMt,
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Damage : Based on the Worst Operating Condition the vessel is analytically damagedby opening various combinations of watertight compartments to the sea. The vessel will
be expected to meet various stability criteria such as freeboard, trim, list, GMt, etc.
p p y ,
area under the Gz curve, range of stability, trim, etc. while subjected to sustained winds,
passenger heeling, maneuvering, lifting, etc.
a) the final waterline after flooding should be below the top of any ventilator coaming, thelower edge of any air pipe opening, the upper edge of the sill of any access opening
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g y p p p g pp g y p g
fitted with a weather-tight door and the lower edge of any other opening through which
progressive flooding could take place.
(b) The angle of heel due to unsymmetrical flooding should not normally exceed 15
degrees but if no part of the deck is immersed an angle of 17 degrees may be accepted.
(c) In the case of symmetrical flooding the metacentric height (GM) calculated using the
constant displacement method should have a positive value of at least 50 mm in the
upright condition after flooding.
(d) The residual stability should be not less than that indicated by the statical stability
curve shown.
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Stability conditions (watercraft)Stability conditions (watercraft) is the term used to describe the various standard
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loading configurations a Ship orBoat may be subjected to. They are recognized by
regulatory authorities such as Lloyd's, American Bureau of Shipping (ABS) and SOLAS.
The conditions describe the Displacement (fluid) or weight of the vessel.
They are normally broken into two classes: Intact and Damage
Intact : The vessel is in normal operational configuration. The hull is notbreached in any compartment. The vessel will be expected to meet various
stability criteria such as GMt, area under the Gz curve, range of stability,
trim, etc. while subjected to sustained winds, passenger heeling,
maneouvering, lifting, etc.
Damage : Based on the Worst Operating Condition the vessel is
analytically damaged by opening various combinations of watertight
compartments to the sea. The vessel will be expected to meet various
stability criteria such as freeboard, trim, list, GMt, etc.
Naval vessels must meet standards described in military standards (ex: MIL-STD,
CFTO) while commercial vessels are regulated by the government of the flag they sail
under and the governments of the ports they operate under.
Intact ConditionsLightship : The vessel is complete and ready for service in every respect, including
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permanent ballast. All flooded spaces such as Sea Chests are considered but the vessel
has no cargo, crew, provisions, ammunition or any other load item.
Light Operating orLight Displacement : Along with all the Lightship loads, the vessel
has all systems charged meaning that all fresh water, cooling, lubricating, hydraulic and
fuel service header tanks, piping and equipment systems are filled with their normal
operating fluids. Crew and effects are at their normal values. Consumables (provisions,
potable water and fuel) are at 10% full load. Ammunition and/or cargo is not included
(0% of full load).
Full Load Departure orFull Displacement : Along with all the Lightship loads, the
vessel has all systems charged meaning that all fresh water, cooling, lubricating,
hydraulic and fuel service header tanks, piping and equipment systems are filled with
their normal operating fluids. Crew and effects are at their normal values. Consumables
(provisions, potable water and fuel) are at 100% capacity. Ammunition and/or cargo is at
maximum capacity. The vessel is at its limiting draft or legal load line.
Standard Condition (Only for Military vessels) : Along with all the Lightship loads, thevessel has all systems charged meaning that all fresh water, cooling, lubricating,
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hydraulic and fuel service header tanks, piping and equipment systems are filled with
their normal operating fluids. Crew and effects are at their normal values. Consumables
(provisions, potable water and fuel) are at 50% capacity. Ammunition and/or cargo is at
100% capacity. This condition is normally used for range and speed calculations.
Light Arrival : Along with all the Lightship loads, the vessel has all systems charged
meaning that all fresh water, cooling, lubricating, hydraulic and fuel service header
tanks, piping and equipment systems are filled with their normal operating fluids. Crew
and effects are at their normal values. Consumables (provisions, potable water and fuel)
are at 10% full load. Ammunition and/or cargo is at 100% capacity.
Additionally: Worst Operating Condition is a loosely defined condition that may have
the least freeboard or least intact stability (or both). This condition forms the baseline for
the Damage Stabilty assessment.
In naval architecture, instantaneous stability is a measure of how a vessel's buoyancy
is distributed. Also known as Intact Stability. Stability is measured by metacentric height.
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Inclining Test
It is easy to check the weight of a vessel by reading draughts and comparing with the
known properties. It is not as easy to check the position of the vertical centre of gravity
(VCG) and yet this dominates stability.
The VCG position can be estimated by moving a weight to produce a known overturning
moment. Knowing the restoring properties (buoyancy) of the vessel from its dimensions
and floating position and measuring the equilibrium angle that the vessel lies at, the
VCG position can be calculated. This is an Inclining Test and it is done inshore in still
water and free of mooring restraints to achieve accuracy.
metacentric height
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Ship Stability diagram, showing Center of Gravity (G), Center of Buoyancy (B), and Metac
The metacentric height (GM) is a characteristic of a ship which helps determine its stabil
Different centers
Initially the second moment of area increases as the surface area increases, increasing B
The center of buoyancy, is the center of gravity of the volume ofwaterwhich the hulldisplaces. This point is referred to as B in naval architecture. The center of gravity of the
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ship itself is known as G in naval architecture. When a ship is upright, the center of
buoyancy is directly below the center of gravity of the ship.
The metacenteris the point where the lines intersect (at angle ) of the upward force of
buoyancyof d. When the ship is vertical it lies above the center of gravity and so
moves in the opposite direction of heel as the ship rolls. The metacenter is known as M
in naval architecture.
The distance between the center of gravity and the metacentre is called the metacentric
height, and is usually between one and two metres. This distance is also abbreviated as
GM. As the ship heels over, the centre of gravity generally remains fixed with respect to
the ship because it just depends upon position of the ship's weight and cargo, but the
surface area increases, increasing BM. The metacentre, M, moves up and sideways
in the opposite direction in which the ship has rolled and is no longer directly over the
centre of gravity.[1]
The righting force on the ship is then caused by gravity pulling down on the hull,
effectively acting on its center of gravity, and the buoyancy pushing the hull upwards;
effectively acting along the vertical line passing through the center of buoyancy and themetacenter above it. This creates a torque which rotates the hull upright again and is
proportional to the horizontal distance between the center of gravity and the metacenter.
The metacentric height is important because the righting force is proportional to the
metacentric height times the sine of the angle of heel.
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Righting arm
Distance GZ is the righting arm: a notional lever through which the force of buoyancyacts.
Sailing vessels are designed to operate with a higher degree of heel than motorized
vessels and the righting torque at extreme angles is of high importance. This is
expressed as the righting arm (known also as GZ see diagram): the horizontal
distance between the center of buoyancy and the center of gravity.[1]
Monohulled sailing vessels are designed to have a positive righting arm (the limit ofpositive stability) at anything up to 120 of heel, although as little as 90 (masts flat to the
surface) is acceptable. As the displacement of the hull at any particular degree of list is
not proportional, calculations can be difficult and the concept was not introduced
formally into naval architecture until about 1970.[2
GM and rolling periodGM has a direct relationship with a ship's rolling period. A ship with a small GM will be
"t d " h l ll i d l GM i th i k f hi i i i
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"tender" - have a long roll period - a low GM increases the risk of a ship capsizing in
rough weather (see HMS Captain orHMS Vasa) and more likely to develop
"synchronized rolling". It also puts the vessel at risk of potential for large angles of heel if
the cargo or ballast shifts (see Cougar Ace). If a ship with low GM is damaged and
partially flooded the metacentric height will be reduced further and make it even lessstable. On the other hand, a too large metacentric height can cause a vessel to be too
"stiff"; excessive stability is uncomfortable for passengers and crew because it quickly
snaps back upright after a wave or wind gust which heeled it over has passed. An overly
stiff vessel rolls with a short period and high amplitude. This can lead to damage to the
ship and cause cargo to break loose or shift. A passenger ship will typically have a long
rolling period for comfort, perhaps 28 seconds while a tanker or freighter might have a
rolling period of 13 to 15 seconds.
Damage StabilityIf a ship floods the loss of stability is due to the free surface effect, as the water
l ti i th h ll ill b i th bil l i th t f it d t ll
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accumulating in the hull will be in the bilges, lowering the centre of gravity and actually
increasing the metacentric height. However once the ship is inclined the centre of gravity
of the fluid in the bilge moves to the low side, resulting in a list, which will reduce the
righting lever (the tendency of the ship to right itself).
Free surface effectFurther information: Free surface effect
I t k th t ti ll fill d ith fl id i fl id (fi h i i f
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In tanks or spaces that are partially filled with a fluid or semi-fluid (fish, ice or grain for
example) as the tank is inclined the surface of the liquid, or semi-fluid, stays level. This
results in a displacement of the centre of gravity of the tank or space. The effect is
similar to that of carrying a large flat tray of water. When an edge is tipped, the water
rushes to that side which exacerbates the tip even further.The significance of this effect is proportional to the square of the width of the tank or
compartment, so two baffles separating the area into thirds will reduce the displacement
of the centre of gravity of the fluid by a factor of 9. This is always of significance in ship
fuel tanks or ballast tanks, tanker cargo tanks, and in flooded or partially flooded
compartments of damaged ships. Another worrying feature of free surface effect is that a
positive feedback loop can be established, in which the period of the roll is equal or
almost equal to the period of the motion of the centre of gravity in the fluid, resulting in
each roll increasing in magnitude until the loop is broken or the ship capsizes.
1. As this ship is required to comply with Schedule 2, Part 1 para. 2 of MSN 1752(M)by the Merchant Shipping (Load Line) Regulations 1998, it is most important to ensure
th t i ili diti th t bilit li t l t ith th f ll i i i
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that in any sailing condition the stability complies at least with the following minimum
criteria:-
Statical stability curve
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HYDROSTATICS
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HYDROSTATIC PARTICULARS
VOLUME DISPLACEMENT ( )
WEIGHT DISPLACEMENT ()
LONGITUDINAL CENTRE OF BUOYANCY (L.C.B)
VERTICAL CENTRE OF BUOYANCY (V.C.B)
LONGITUDINAL CENTRE OF FLOATATION (L.C.F)
TRANSVERSE METACENTRIC RADIUS (BMT)
LONGITUDINAL METACENTRIC RADIUS (BML)
MOMENT TO CHANGE TRIM BY 1 cm (MCTI)
TONES PER CENTIMETER IMMERSION (TPC)
WETTED SURFACE AREA
FORM COEFFICIENTS
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Th t t d h i t i (CT) f i h F d i
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The moment necessary to produce a change in trim (CT) of one inch. Found using
the Draft Diagram and Functions of Form.
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complex; a hold can, for instance, be assessed forgrain (accounting for all the air space i
n, crew spaces, etc., again with differences depending on which port orcountry is doing th
always larger than gross register tonnage, though by how much depends on the vessel de
, 1969 (London-Rules)), which applies to all ships built after July 1982. In accordance with
in m and K= a figure from 0.22 up to 0.32, depending on the ships size (calculated by :).me of all cargo spaces of the ship. It indicates a vessels earning space and is a function
ortant; since a ships registration fee, harbour dues, safety and manning rules etc, are bas
odified for Panama Canal purposes. PC/UMS is based on a mathematical formula to calc
ther volumetric system, generally used for small vessels such as yachts; it uses a formula
eir lifetime, often confuse "Tonnage" and "Ton". Please note that "Tonnage" refers to the u
Longitudinal Center of Flotation (LCF ) Geometric center of the ship's waterline
plane. The ship trims about this point.
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plane. The ship trims about this point.
May be forward or aft of the MP depending
on the ship's hull shape at the waterline.
Center of Flotation Distance:
Distance from the LCF to the MP. Found using the Draft Diagram and Functions of
Form, as a function of displacement. Used to distribute changes of trim between the fwd
and aft drafts.