N. B. B. 263-16

NEVERSAIL

INCLINING EXPERIMENT, U. S. S.

(Sheet

of

)

Axis assumed

feet above base line

Buships No.

Vessel considered water-tight to

Taken from Plan No.

Scale of Tons Displacement

M

12,000

13,000

15,000

9,000

11,000

14,000

10,000

NATURAL

SINE

ANGLE

SINE

ANGLE

SINE

0

.7660

0

50

.8660

.1736

10

60

.9397

70

.3420

20

80

30

.9948

.5000

1.0000

40

90

.6428

6

o

50

(e)

o

40

60o

5

o

50

(d) (f)

o

70

40o

(g)

o

30

o

60

(c)

o

70

4

30 o

o

80

(h)

80o

o

20

3

(b)

o

o

90

20

o

90

(i)

2

o

10

o

10

(a)

1

0

N

DCf1226

ship's center of gravity (G). To use a curve taken from

read the corresponding value of the righting arm on the

vertical scale at the left. Then plot this value of the

the cross curves, therefore, it is necessary to correct the

righting arm at the corresponding angle of heel on the

curve for the ACTUAL height of G above the keel

grid for the stability curve. When you have plotted a

(KG). If the distance KG is not known and a number of

series of such values of the righting arms from 10° to

weights have been added to or removed from a ship,

90° of heel, draw a smooth line through them and you

KG can be found by the use of vertical moments. A

have the UNCORRECTED stability curve for the ship

vertical moment is the product of the weight times its

at that particular displacement.

vertical height above the keel. As far as the new center

In figure 12-27, curve A represents an uncorrected

of gravity is concerned, when a weight is added to a

stability curve for the ship while operating at

system of weights, the center of gravity can be found

11,500 tons displacement, taken from the cross curves

by taking moments of the old system plus that of the

shown in figure 12-26. This stability curve cannot be

new weight and dividing this total moment by the total

used in its present form, since the cross curves are

final weight. Detailed information concerning changes

made up on the basis of an assumed center of gravity. In

in the center of gravity of a ship can be obtained from

actual operation, the ship's condition of loading will

affect its displacement and therefore the location of the

12-14