ship stability, naval architecture,
transverse stability, ship, naval architecture, seaworthy, gravity, buoyancy,
metacenter, titanic, tankers, ballast, gravity,
buoyancy, flooding in Marine Engineer Shipping, Naval Architecture, Ship
Transverse Stability, Marine, Engineer, Engineering, Shipping, Ship, Equipment,
Machinery, Merchant Shipping
How do we determine whether a ship is seaworthy or not?
Although there are many factors that will affect
seaworthiness, we can generally agree that a ship is seaworthy when it is
fit to carry the cargo in protected condition and deliver it to the
Assuming that the propelling machinery are all in good
condition, the ship needs to be strong, have sufficient freeboard and is
This page tells a bit about transverse stability.
To learn more about the calculations on Transverse
Stability and other Naval Architecture topics, download our Free e-book,
"Naval Architecture Questions &
Answers". This e-book is written for Marine Engineers who wishes to sit
for the Naval Architecture Subject for Certificate of Competency Class 1
|Whenever a ship
floats on the water, there are 2 forces acting on it - the gravity force and
the buoyancy force.
When the cargo in the ship
are evenly distributed, the ship will be upright. The sum of the gravity
forces of cargo and the ship will be acting at one point - the Center of
Gravity, G, acting downwards.
Similarly, the Center of Buoyancy of the ship will be
acting at one point B, acting upwards.
However, during rough weather, the ship may be tossed
about by the waves or the wind to heel towards one side. At this moment, the
Center of Buoyancy will shift to another position, B1. This
buoyancy force acting upwards, tends to turn the ship back towards upright
A ship is said to be in Stable Equilibrium if on being
slightly inclined, tends to return back to the original position. However, a
ship will be in Unstable Equilibrium when she tends to move further from
that original position on being tilted slightly. A ship in Neutral
Equilibrium will tend to neither return nor move further from that position.
Looking at the drawing on the left, a ship at upright
is in Stable Equilibrium when the center of gravity, G is below M.
A ship is in unstable equilibrium when G is above M.
At neutral equilibrium, G and M coincides.