Stability- SQA exam UPDATED ACTUAL
Exam Questions and CORRECT Answers
Mass - CORRECT ANSWER - Mass is the fundamental measure of the quantity of matter
in a body and is expressed in kilograms or tonnes.
Volume - CORRECT ANSWER - the amount of space, measured in cubic units, that an
object or substance occupies. Expressed in Cubic metres
Density - CORRECT ANSWER - The density of any given substance is its mass per unit
volume.
Expressed in tonnes per cubic metre
Relative Density - CORRECT ANSWER - The ratio of the density of any substance to the
density of some other substance taken as standard. Water being he standard for liquids.
Archimedes principle - CORRECT ANSWER - States that when a body is fully or
partially immersed in a liquid, it experiences an upthrust (apparent loss of mass termed buoyancy
force), equal to the mass of liquid displaced.
FWA - CORRECT ANSWER - Number of millimetres by which the mean draught changes
when a ship passes from salt water to fresh water when the ship is loaded to summer
displacement.
DWA - CORRECT ANSWER - Number of millimetres by which the mean draught
changes when a ship passes from salt water to dock water when the ship is loaded to summer
displacement.
TPC (tonnes per centimetre immersion) - CORRECT ANSWER - The TPC for any given
draught is the weight which must be loaded or discharged to change the ships mean draught by
1cm.
, LBP (length between perpendiculars) - CORRECT ANSWER - Is the horizontal distance
between the forward and after perpendiculars. It is this length that is considered when conducting
trim calculations.
CW (coefficient of fineness of the water-plane area) - CORRECT ANSWER - Is defined
as the ratio of the ships water-plane area to the area of a rectangle having the same length and
breadth of the ship at the waterline in question
CB (block coefficient) - CORRECT ANSWER - The block coefficient (CB) of a ship is the
ratio of the underwater volume of a ship to the volume of the circumscribing block. Value must
be less than 1.00.
Explain what is meant by Equilibrium - CORRECT ANSWER - Equilibrium is the term
used to describe a vessel that is afloat. It is a word made up of two words namely equal, and
balance. A vessel will float when the forces of weight and buoyancy are equal, and they balance -
that is both B and G are in the same vertical line, and the vessel is not being acted on by an
external force (a force other than buoyancy or weight).
Freeboard - CORRECT ANSWER - The vertical distance from the summer load line to the
freeboard deck. The freeboard deck is normally the uppermost complete deck exposed to weather
and sea.
Water plane area(WPA) - CORRECT ANSWER - The enclosed area of the hull at the
waterline is the waterplane area. The Water-plane area is used to determine the TPC of a ship.
Centre of gravity - CORRECT ANSWER - Is the point through which the total weight
force (wf) of the ship can be considered to act vertically downwards. It's position will depend
upon the distribution of the weight of the vessel and everything on board.
Whenever weights are shifted, loaded or discharged G will move.
DRAW DIAGRAM
Centre of buoyancy - CORRECT ANSWER - Is the geometric centre of the underwater
volume of the ship. It is the point through which the total force of buoyancy is considered to act
Exam Questions and CORRECT Answers
Mass - CORRECT ANSWER - Mass is the fundamental measure of the quantity of matter
in a body and is expressed in kilograms or tonnes.
Volume - CORRECT ANSWER - the amount of space, measured in cubic units, that an
object or substance occupies. Expressed in Cubic metres
Density - CORRECT ANSWER - The density of any given substance is its mass per unit
volume.
Expressed in tonnes per cubic metre
Relative Density - CORRECT ANSWER - The ratio of the density of any substance to the
density of some other substance taken as standard. Water being he standard for liquids.
Archimedes principle - CORRECT ANSWER - States that when a body is fully or
partially immersed in a liquid, it experiences an upthrust (apparent loss of mass termed buoyancy
force), equal to the mass of liquid displaced.
FWA - CORRECT ANSWER - Number of millimetres by which the mean draught changes
when a ship passes from salt water to fresh water when the ship is loaded to summer
displacement.
DWA - CORRECT ANSWER - Number of millimetres by which the mean draught
changes when a ship passes from salt water to dock water when the ship is loaded to summer
displacement.
TPC (tonnes per centimetre immersion) - CORRECT ANSWER - The TPC for any given
draught is the weight which must be loaded or discharged to change the ships mean draught by
1cm.
, LBP (length between perpendiculars) - CORRECT ANSWER - Is the horizontal distance
between the forward and after perpendiculars. It is this length that is considered when conducting
trim calculations.
CW (coefficient of fineness of the water-plane area) - CORRECT ANSWER - Is defined
as the ratio of the ships water-plane area to the area of a rectangle having the same length and
breadth of the ship at the waterline in question
CB (block coefficient) - CORRECT ANSWER - The block coefficient (CB) of a ship is the
ratio of the underwater volume of a ship to the volume of the circumscribing block. Value must
be less than 1.00.
Explain what is meant by Equilibrium - CORRECT ANSWER - Equilibrium is the term
used to describe a vessel that is afloat. It is a word made up of two words namely equal, and
balance. A vessel will float when the forces of weight and buoyancy are equal, and they balance -
that is both B and G are in the same vertical line, and the vessel is not being acted on by an
external force (a force other than buoyancy or weight).
Freeboard - CORRECT ANSWER - The vertical distance from the summer load line to the
freeboard deck. The freeboard deck is normally the uppermost complete deck exposed to weather
and sea.
Water plane area(WPA) - CORRECT ANSWER - The enclosed area of the hull at the
waterline is the waterplane area. The Water-plane area is used to determine the TPC of a ship.
Centre of gravity - CORRECT ANSWER - Is the point through which the total weight
force (wf) of the ship can be considered to act vertically downwards. It's position will depend
upon the distribution of the weight of the vessel and everything on board.
Whenever weights are shifted, loaded or discharged G will move.
DRAW DIAGRAM
Centre of buoyancy - CORRECT ANSWER - Is the geometric centre of the underwater
volume of the ship. It is the point through which the total force of buoyancy is considered to act
