What measurement is known by the term
the commanding officer of the ship outlining the
necessary work to be done by the ship's force and by
the yard to prepare the ship for the inclining.
Distance in feet from the keel to the
The results of the experiment are furnished to each
ship as a "booklet of inclining experiment data." This
Distance from the waterline to the weather
booklet contains data on displacement, the center of
gravity above the keel (KG), and overall stability for
the operating conditions of load. Detailed information
Distance from the bow to the stern
on the inclining experiment can be obtained from
Distance from the portside to the
Naval Ships' Technical Manual (NSTM), chapter 096,
starboard side of the ship
"Weights and Stability."
Which of the following information is NOT
contained in the "booklet of inclining
Data on displacement
Detailed information on the laws of
mathematics and physics used to determine
The center of gravity above the keel
the buoyancy and stability of a ship are
provided in Naval Ships' Technical Manual
(NSTM), chapter 079, volume 1, and in
NSTM, chapter 096.
ANALYSIS OF STABILITY
Learning Objectives: Recall the laws of physics and
trigonometry used to determine stability and buoyancy
Which of the following trigonometric
of a ship; and the effects of buoyancy, gravity, and
functions is NOT used for making
weight shifts on ship stability.
calculations to determine a ship's stability?
To analyze stability principles, you must be
familiar with the terms, definitions, and equations that
are used to express important relationships. These are
· G, the ship's center of gravity, is the point at which
all weights of the ship may be considered to be
concentrated. The force of gravity is considered
Which of the following terms best defines
as acting straight downward, through the center of
force multiplied by the distance from an axis
gravity, at right angles to the waterline.
about which you want to find its effect?
· B, the ship's center of buoyancy, is at the
geometric center of the ship's underwater hull.
Moment of force
When a ship is at rest in calm water, the forces of
B and G are equal and opposite, and the points B
and G lie in the same vertical line. When the ship
is inclined, B and G move apart, since B moves
off the ship's centerline as a result of the change
in the shape of the underwater hull.
The volume of water that is moved by the hull
of a ship is known as "displacement."
· M, the ship's metacenter, is a point established
by the intersection of two successive lines of
buoyant force as the ship heels through a very