Stability Flashcards
Intact stability criteria?
GM 0.15m
Max GZ 0.20m at min angle 25°
Ares under GZ curve 0-30° 0.055mrad
AUC GZ curve 30-40°/DEI 0.030mrad
AUC 0-40°/DEI 0.090mrad
Calculation of FWA?
Displacement / (4xTPC)
Dock Water Allowance calculation? (mm)
FWA X ((1025-DWdensity)/25)
Application: FWA
TPCsw = 17
∆sum = 13000
What is FWA in CENTIMETRES?
FWA(mm) = ∆/(4xTPC)
FWA(mm) = 13000/(4x17) = 191mm
191mm = 19.1 cm
Timber Stability Criteria?
AUC 0-40°/DEI 0.080mrad
Minimum GZ = 0.25m
GM at all times 0.10m
16° limiting angle of heel under steady wind
What is a KN Curve?
Cross Curve of Stability
Developed, so that, for any loading condition (where KG is already known), values of righting lever (GZ) can be obtained for all angles of heel.
What is transverse statical stability?
The ability of a ship to return to upright after being inclined by an external force
What is the righting lever?
The horizontal distance between the centre of gravity and the vertical line of buoyancy force acting through the centre of buoyancy when the vessel is inclined
Where is the centre of buoyancy?
The geometric centre of underwater volume
What is the ideal GM?
Between 4 - 8% of the ship’s breadth
If this is the answer, what is the question:
4-8%
Refers to ships breadth and Ideal GM value
What is this?
What can you tell me?
Plimsoll Mark, located amidships. This particular example is from the port side, as the Lumber Lines are toward the stern of the vessel.
Outer Diameter of Ring: 300mm
All lines 25mm thick
Loadline Stalks - 230mm long
Plimsoll Line 450mm long, with letters of RO outside ring
Loadline branches located 540mm fwd or aft of centre of Plimsoll Ring
WNA 50mm below Winter Line
Plimsoll line same as summer draft
Tropical and Winter = 1/48th of Summer Draft above or below Summer Line
