Page 288 - Practical Design Ships and Floating Structures

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2 EFFECT OF DEGREE OF DETAILS IN THE SUBDMSION ON THE ATTAINED INDEX

In the probabilistic damage stability analysis the survivability factor s is calculated for any combina-
tion of adjacent damage compartments. Hence, if s=l for a two compartment damage, the bulkhead
separating these compartments can be omitted without changing the Attained Index A. Thus a good
estimate of A can be expected even if several minor compartments are combined in a single compart-
ment. This is often the case in the engine room and the side casing and will be illustrated in the follow-
ing. The ship considered is a Ro-Ro passenger ferry with general arrangement and main dimensions as
given in Figure 1. The subdivision shown corresponds to layout #1, defined in Table 1.
. ......... ? .._ '\ . ............. ..*
-.
it !.. ............. ; ... ............ . ....... ....--
<,A<. ..-, I "^ ;
/' \

_...._.......... ....................................... -
.......................................

-----...- "- ...... ~.....I ............................................................... y----*.+---

Number of
Subdivisior compartments Description of layout
Layout#l 33 All longitudinal bulkheads except for heeling tanks removed
Layout #2 21 As #1, but all horizontal subdivisions below main deck removed
As #2, but transverse subdivisions removed below main deck to yield 4 large
Layout #3 13 compartments
LayoutM 11 As #3, but volume below main deck reduced to 2 large compartments