Page 369 - Practical Ship Design

326 Chapter I I

1 .o J=O

0.8 Reduction factor (r) for wing
r compartments
0.6 Wing compartments only p, . r
Simultaneous flooding of
0.4 wing and centre P,(l - r)
Interpolate for J < 0.2(blB)
0.2

0
0 0.1 0.2 0.3 0.4 0.5
blB

Fig. 11.7. Probabilistic subdivision of cargo ships. Reduction factor for wing compartments (r).
Formulae:

J 202blB r=blB [ 23+- Jz02]+01 ifblBIO2

+bl
B
+036]
r = [s if b I B >02
J +0.02
Some general guidance which can be given from passenger ship experience
suggests:
- avoid longitudinal subdivision if possible and where it is essential cross
connect the wing compartments with automatically operating ducts or pipes;
- think very carefully before introducing horizontal subdivision as damage
above this may result in a loss of waterplane inertia without the benefit of
added weight low down;
- choose dimensions that will ensure good stability and range before damage to
help to ensure that the s value after damage is good;
- make compartments generally of about the same length so that each contri-
butes fairly equally to A. If longer compartments are required, try to locate
these in the forebody, where they will benefit from a higher a value (see Fig.
1 1.4).

Opposite: Fig. 11.8. Probabilistic subdivision of cargo ships.
(a) S/C versus GZ x range.
(b) C versus final angle 0.
(c) (H - 4l(Hmax - 4 versus H - d.