Stability Flashcards
What is displacement?
The weight of the vessel measured in tonnes.
What is Load Displacement?
The weight of the vessel when down to her summer load line marks.
What is Light Displacement?
The weight of the ship when empty of all stores, cargo, ballast, fuel, water and crew etc.
What is Deadweight?
The difference between the light displacement and the present displacement.
What is GT?
Gross Tonnage is the vessels total internal volume expressed in register tons.
What is NT?
Net tonnage is the GT minus the spaces not available to carry cargo, such as accommodation or the engine room.
What is TPC?
TPC is the amount of weight required to change the vessels draft by 1cm.
What is FWA/DWA?
The amount that the vessel can submerge her marks when in fresh water or dock water, measured in mm.
What is FSE?
created by movement of liquids surface in a slack tank.
Define GZ
Righting lever is the perpendicular distance between the buoyancy and weight forces as the vessel is subjected to heel.
Define GM
The vertical distance between the COG and the meta centre.
Define KG
Keel to COG
Define KM
Keel to Metacentre
Define MCTC
Moments to change trim by 1cm
Define LCG
Longitudinal COG, measured forward from the aft perpendicular.
Define LCB
Longitudinal COB, measured fwd from aft perpendicular.
List vs Heel
Internal vs External
What is an angle of loll and how is it corrected?
When a vessel is in unstable equilibrium, negative GM, any external force will create heel which cannot be corrected as there is no righting lever due to the negative stability.
Filling of bottom tanks is required to increase the height of M.
What is the minimum GM allowed?
0.15m, 0.30m for grain, 0.10m for timber.
Formula for DWA
FWA x (1025-d)
DWA = ———————
25
