NEW
Font size
WorksheetsSEAM 6 - Quiz 6 (2nd Sem 2025-2026)
Total questions: 70
Worksheet time: 35mins
List is defined as the angle of heel when a ship is in which condition?
Upright in still water with no external forces
Permanently inclined to one side in upright condition
Temporarily heeled by wind and wave action
At rest with asymmetrical weight distribution
When a weight is loaded off-centre to the starboard side, the ship's centre of gravity moves in which direction?
Vertically upward toward the deck
Horizontally to starboard and vertically
Vertically downward toward the keel
Horizontally to port only, no vertical change
The shift of G horizontally when a weight is loaded off-centre is calculated by which formula component?
GGH = Weight times distance off centreline divided by displacement
GGH = Weight times vertical distance divided by displacement
GGH = Displacement times distance off centreline divided by weight
GGH = Distance off centreline times initial KG divided by weight
In the list triangle, when GGH is the distance G is off the centreline, what does GM represent?
The distance from keel to metacentre minus KG value
The distance from G to M including free surface effect
The distance from initial position to heeled position
The vertical distance between G and the waterline
The formula Tan θ LIST = GGH divided by GM is used to calculate which stability parameter?
The angle of list when G is off the centreline
The permanent heel angle in calm water conditions
The metacentric height at a specific draught
The righting moment available at heel angle
When a single weight is shifted horizontally across the centreline, what is the effect on KG?
KG remains unchanged as weight moves horizontally
KG increases proportionally to the horizontal shift
KG decreases due to horizontal movement of weight
KG increases or decreases based on vertical position
In a ship with negative GM, if the vessel is heeled beyond small angles, at what angle may it come to rest?
At zero degrees when external force is removed fully
At an angle of loll where B is directly below G
At the maximum possible heel angle the hull permits
At the angle where righting moment becomes positive
When calculating the final list from multiple weights loaded off-centre, which method is most practical?
Sum individual list contributions and add arithmetically
Take moments about keel and moments about centreline
Use the Tan θ formula for each weight separately only
Apply GGH calculation to each weight independently
If a ship is initially listed to starboard, how must GGH be incorporated in stability calculations?
It is calculated using Tan θ LIST multiplied by the initial GM
It is added to new listing moments from cargo operations
It is subtracted from all subsequent weight movements
It is ignored in calculations and moments start from zero
When loading a weight using a ship's derrick on one side, at what point does maximum list typically occur?
When the weight is landed in its final stowage position
When the weight is suspended at maximum derrick height
When the derrick starts to swing inboard to centreline
After the weight has been fully secured in lower hold
What is the relationship between free surface effect and the angle of list for the same GGH distance?
Free surface effect increases GM, reducing list angle
Free surface effect reduces GM, increasing list angle
Free surface effect does not affect list angle at all
Free surface effect affects only vertical stability parameter
When a ship lists permanently to one side due to off-centre loading, which force condition creates this?
The weight and buoyancy forces act in same vertical line
The lines of action of weight and buoyancy forces are parallel
The lines of action intersect below the metacentre M
The centre of buoyancy moves ahead of centre of gravity
In the list triangle GGM, if GM value decreases while GGH remains constant, what happens to list?
List angle decreases due to increased righting moment
List angle increases due to reduced righting lever
List angle remains unchanged with GM reduction
List angle decreases proportionally to GM change
What is the purpose of calculating both vertical and horizontal components when loading a weight off-centre?
Vertical component affects KG while horizontal affects list
Both components affect KG only, list is separate calculation
Vertical component affects displacement only, horizontal affects trim
Both components must be considered for total stability effect
When completing loading with cargo in two compartments either side of centreline for an upright ship, what must be true?
Port moments must equal starboard moments about centreline
Total vertical moments must equal total horizontal moments
Port and starboard weights must be exactly equal in mass
All weights must be loaded at the same height above keel
If ballast water is loaded 5.0 m to starboard of centreline, the ship will list to which direction?
To port, due to symmetrical loading principle
To starboard, in the direction of weight loading
To port initially, then starboard finally after settling
Upright because ballast provides stability balance
In a multiple weight problem with the ship initially upright, what does the initial GGH value equal?
Zero, as the centre of gravity is on the centreline
The KG value multiplied by sin(0) where 0 is list angle
Half the total horizontal distance to furthest load
The sum of all individual horizontal weight movements
When a weight is discharged from the starboard side of the vessel, which direction will the list change?
Ship will list to starboard due to weight removal
Ship will list to port, away from weight discharge
Ship remains upright if it was upright initially
Ship will list to whichever side has more cargo aboard
The formula GGH=w×d/W is used when calculating horizontal shift of G for which operation?
Discharging cargo from a specific position off-centre
Loading cargo into a position off-centre to the hull side
Shifting existing cargo from port to starboard side
All of the above operations of weight position changes
In a list calculation, if the final GGH calculated is 0.0 m0.0\,\text{m}0.0m , what is the final list angle?
Zero degrees, ship is perfectly upright
Some angle determined by residual free surface effect
The angle of loll for the vessel's particular design
Indeterminate, and ship may list at any small angle
When taking moments about the centreline to determine listing, what is the 'moment arm' for off-centre weights?
The vertical distance from keel to weight centre of gravity
The distance from the centreline to weight position laterally
The horizontal distance from the waterline to the weight
The diagonal distance from keel to off-centre weight position
In the list triangle, the vertical side represents which parameter of ship stability?
The angle of list in degrees or radians measured
The distance G is off-centre from the centreline
The metacentric height with or without free surface
The righting moment available at small list angles
If a ship is loaded such that port moments and starboard moments are unequal, what will result?
The ship will remain upright due to hydrostatic forces
The ship will develop a permanent list to heavier side
The ship will heel temporarily then return to upright
The ship will sink deeper on the heavier loaded side
When calculating moments about the centreline, which of the following creates a negative moment value?
Weight loaded above the keel height at any lateral position
Weight on the port side of the centreline measured
Weight discharged from the starboard side of centreline
Weight shifted from port to starboard transversely
The phenomenon where a vessel inclined to one side is 'pulled' to heel further when negative GM exists is due to which force couple?
Weight force and buoyancy force forming a heeling couple
Buoyancy force greater than weight force combined effect
Hydrostatic pressure on hull sides being unequal laterally
Wind heel moment acting on the exposed upper hull area
When the ship is listed initially and cargo is worked, what must be done for accurate list calculation?
Ignore initial list and calculate as if ship were upright
Calculate initial GGH from tan(LIST)×GM and include it
Add initial list angle directly to final calculated list angle
Subtract initial list angle from all new cargo moment effects
In the formula tanθ=GGHGM\tan \theta = \dfrac{GGH}{GM}tanθ=GMGGH , if θ\thetaθ increases while GMGMGM stays constant, what must have changed?
GGH has increased due to more off-centre loading
The ship's displacement has decreased proportionally
The centre of buoyancy has shifted outboard significantly
The initial KG value has been reduced by discharging cargo
When ballast is transferred from one double-bottom tank to another across the centreline, which parameter changes first?
The KG of the ship increases due to vertical shift
The final list angle changes due to lateral moment transfer
The metacentric height GM is immediately affected
The ship's displacement changes due to ballast water movement
If a ship has 0.100m horizontal off-centre distance (GGH) and a GM of 1.00m , what is the approximate list angle?
Approximately 5.7 degrees angle of list developed
Approximately 2.9 degrees angle of list developed
Approximately 11.4 degrees angle of list developed
Cannot be determined without knowing ship's displacement
In list calculations using the moments table method, the first entry must be which item?
The initial ship displacement and its initial KG value
The largest weight to be loaded or discharged first
The total of all weights to be worked during operation
The centre of gravity position at the start of loading
When loading cargo that will create list, at what point is the angle of list actually determined?
During the loading process at each cargo discharge
Only after all cargo has been loaded and stowed
At the moment each individual cargo parcel is placed
Continuously as each cargo parcel is secured in place
In a multiple weight problem where some cargo is loaded off-centre and some on-centre, which creates list?
Only the off-centre cargo creates listing moments
All cargo contributes equally to the list effect
The net result of all moment contributions determines list
On-centre cargo doubles the effect of off-centre cargo
If the calculated final GGH is to port and GM is 0.80m , which side does the ship list to?
Ship lists to starboard due to negative moment value
Ship lists to port in the direction of GGH calculation
Ship remains upright as GGH value is very small
Ship lists to whichever side has greater water density
The horizontal component of G shift (GGH) is independent of which stability factor?
The location of the loaded or shifted weight horizontally
The vertical position or height above the keel (KG)
The ship's total displacement at any given loading state
The distance the weight moves laterally from original position
When calculating list in a tabular form, how are off-centre weights entered for moments about the centreline?
As negative values for port and positive for starboard
Distance off centreline multiplied by weight creates moment
Shown in separate port and starboard moment columns
All of the above methods are used depending on situation
Trim is defined as the difference between which two draught measurements on a ship?
The mean draught and the maximum draught at any point
The draught forward and the draught aft at perpendiculars
The light ship draught and the loaded ship draught overall
The draught at the waterline and draught at the deck level
Forward draught (Df) is measured at which location on the ship's length?
At the forward perpendicular of the vessel's registered length
At the bow at the lowest point above water surface
At midships point halfway between bow and stern perpendiculars
At the stem where the bow meets the waterline tangentially
Aft draught (Da) is measured at which location on the ship's length?
At the aft perpendicular of the vessel's registered length
At the stern at the lowest point above water surface
At the rudder post where stern meets the rudderstock
At midships point halfway between bow and stern perpendiculars
The mean draught (Dm) is calculated by which formula from forward and aft draughts?
Dm = Df + Da divided by 2 for average of two measurements
Dm = Df minus Da plus the ship's length overall value
Dm = larger value of Df or Da whichever is deeper
Dm = the half-length distance between two perpendiculars
What is the definition of a ship floating on an 'even keel' condition with respect to trim?
The draught forward equals the draught aft, trim equals zero
The centre of gravity is directly below the centre of buoyancy
The ship is floating parallel to the water surface at all points
Both A and C are correct definitions of even keel state
When a ship floats with draught forward greater than draught aft, this is called which condition?
The ship is trimmed by the stern (aft end lower)
The ship is trimmed by the head or bow (forward end lower)
The ship is in unstable equilibrium condition overall
The ship is floating with list to the starboard side
When a ship floats with draught aft greater than draught forward, this is called which condition?
The ship is trimmed by the head or bow angle
The ship is trimmed by the stern with aft end deeper
The ship is floating at the summer load line mark
The ship is developing a permanent list condition
The longitudinal centre of flotation (LCF) is defined as which point on a ship?
The geometric centre of the waterplane area of the ship
The centre of gravity location along the ship's length
The forward perpendicular position of the vessel's design
The midpoint between bow and stern structural points
The moment to change trim one centimetre (MCTC) represents which parameter in trim calculations?
The force required to change the ship's trim by 1.00 cm
Weight times distance required to change trim by 1.0 cm
The metacentric height multiplied by ship's length overall
The buoyancy moment acting at the centre of flotation point
When a weight is loaded forward of the LCF position, what trim change occurs?
The ship trims by the head (forward end becomes deeper)
The ship trims by the stern (aft end becomes deeper)
No trim change occurs, only vertical sinkage results
The ship develops a permanent list to one side only
When a weight is loaded aft of the LCF position, what trim change occurs?
The ship trims by the head with bow becoming deeper
The ship trims by the stern with stern becoming deeper
No trim occurs, forward perpendicular changes
The ship develops list and trim simultaneously always
If a weight is loaded exactly at the LCF position, what is the trim change?
Trim changes by the full sinkage amount calculated
Trim remains unchanged, only draught changes uniformly
Trim is affected minimally due to location at LCF
Trim cannot be calculated without knowing ship's length
The MCTC value varies with which ship parameters affecting trim calculations?
Only the displacement and ship's length overall value
Only the draught and the metacentric height KM value
Displacement, draught, and longitudinal stability parameters
The height of the centre of gravity and list angle only
The relationship between load moment and trim change is expressed by which formula?
Trim change (cm) = Load moment (t·m) divided by MCTC
Trim change (cm) = MCTC multiplied by weight times distance
Trim change (cm) = Weight times distance divided by ship length
Trim change (cm) = Distance from LCF times MCTC divided by weight
In trim calculations, when a weight is shifted from forward to aft along the ship's length, what results?
The trim by the head changes to trim by the stern
The trim by the stern changes to trim by the head
Both forward and aft draughts increase equally throughout
The ship's displacement and total draught remain constant
The hydrostatic data tables provide MCTC values that change with which draught condition?
MCTC values remain constant regardless of ship's draught
MCTC increases proportionally as draught increases linearly
MCTC values change with draught and must be interpolated
MCTC is the same for all load conditions and draughts
When calculating trim change, the reference point from which distances are measured is which point?
The forward perpendicular of the ship's registered length
The longitudinal centre of flotation (LCF) position
The midships point between perpendiculars of the vessel
The centre of gravity of the ship at loading commencement
In the formula for trim change, what does the denominator in the MCTC calculation represent?
The total length of the ship from bow to stern overall
The registered length between forward and aft perpendiculars
The moment required to change trim by one centimetre
The distance in metres of one centimetre trim in t·m terms
When multiple weights are loaded at different longitudinal positions, how is the total trim change calculated?
Sum the individual load moments and divide by total MCTC
Calculate trim for each weight separately and add results
Average the distances and divide by ship's length overall
Use only the furthest weight from LCF in the calculation
If MCTC is 95 t·m and a weight of 100 t is loaded 50 m forward of LCF, what is trim change?
Approximately 52.6 cm trim by the head change occurs
Approximately 26.3 cm trim by the head change occurs
Approximately 104 cm trim by the head change occurs
Cannot be calculated without knowing ship's displacement
The LCF position expressed as a percentage of the ship's length relates to which ship characteristic?
The naval architecture form coefficient and underwater hull shape
The proportional loading distribution from bow to stern
The distance where no trim change results from loading
All of the above characteristics affect LCF position
When a weight is discharged from forward of the LCF, in which direction does trim change?
The ship trims by the stern as forward end becomes lighter
The ship trims by the head as aft end becomes heavier
The draught forward decreases while draught aft increases
Both A and C describe the same trim change effect
The total trim of a ship is related to the algebraic sum of which parameters during loading operations?
All individual load moments forward and aft of LCF position
The displacement changes and the draft changes at each end
The metacentric height and the distance from centre of buoyancy
The centre of gravity position and the beam of the vessel
In calculating trim from hydrostatic curves, which of the following must be determined first?
The ship's final displacement and corresponding mean draught
The LCF position for both initial and final load conditions
The moment to change trim value (MCTC) at the draught
All of the above parameters must be established initially
Forward perpendicular (FP) and aft perpendicular (AP) are defined as which reference lines?
They mark the extreme length of the ship's underwater hull form
They define the registered length for trim measurement purposes
They indicate where the load lines are permanently marked
They show the points where the deck joins the hull structure
If a ship's initial trim is 1.5 m by the stern and cargo is loaded causing 0.8 m trim by the head, what is final trim?
2.3 m by the stern as trim changes accumulate total
0.7 m by the stern after subtracting head trim effect
0.8 m by the head as it overwrites initial trim value
1.15 m by the stern as average of both conditions
When determining trim change, the distance from LCF must be measured in which direction?
Perpendicular to the waterline in the transverse plane
Along the ship's length from LCF to weight position longitudinally
Vertically from the keel to the weight's centre of gravity
Diagonally from the LCF to the weight's actual location
The LCF position on most merchant ships is typically located where relative to midships?
Exactly at the midships point between forward and aft perpendiculars
Slightly forward of midships due to typical hull form underwater
Significantly aft of midships on all commercial vessels
At a variable position depending on the draught continuously
In trim calculations using MCTC, what assumption is made about the change in MCTC during loading?
MCTC remains absolutely constant throughout the loading operation
MCTC changes linearly with the weight changes during loading
MCTC is assumed constant for small loading changes approximately
MCTC varies in a non-linear manner requiring interpolation always
If the LCF is located at 55% of the ship's length from forward perpendicular, where is this position?
Forward of midships point (50% of the length from FP)
Aft of midships point at 5% of the length measurement
Exactly at the midships point where trim pivot occurs
Cannot be determined without knowing the ship's overall length
When a weight is shifted aft along the ship's length, how is the trim moment calculated for this operation?
Trim moment = weight times the distance between two compartment positions
Trim moment = weight times longitudinal distance shifted only
Trim moment = weight times distance from LCF to new position
Trim moment requires using the original position relative to LCF
In loading problems, the change in forward draught (ΔDf) and change in aft draught (ΔDa) are related by which principle?
ΔDf equals ΔDa in all loading and discharge operations
ΔDf plus ΔDa divided by 2 equals change in mean draught
ΔDf and ΔDa depend on weight position relative to LCF
ΔDf and ΔDa are independent and calculated separately always
When calculating new forward and aft draughts after loading, which formula is used?
Df final = Df initial plus sinkage plus forward trim component change
Df final = Df initial plus entire trim change at forward perpendicular
Df final cannot be calculated independently without aft draught
All trim changes occur equally at both perpendiculars always
In hydrostatic data tables, the MCTC value is influenced primarily by which ship design parameter?
The second moment of inertia of the waterplane area about LCF
The block coefficient and the underwater hull form characteristics
The length of the ship and the stability characteristics combined
All of the above factors contribute to the MCTC value
After completing loading, to verify the final trim is correct, which draught measurement should be taken?
Only the mean draught at the midships point measured independently
Both forward and aft draughts at perpendiculars for verification
The forward draught only as it controls load line compliance
The aft draught only as it indicates the ship's stability condition
