Page 358 - Practical Ship Design

Freeboard and Subdivision 315

Machinery space

Spaces forward and aft U = 63 + 35 ah
respectively of machinery space
a = volume of space for passengers within the volume v
c = volume of space used for cargo,stores or coal within the volume v
v = total volume to the margin line of the portion of the ship under
consideration
Detailed calculations may be allowed in unusual cases, one of these being the
presence of “intact buoyancy” - see 9 12.5.1. for extent of damage assumptions.
The factor of subdivision (F) depends firstly on the shp’s service, i.e., whether the
ship is to be certified for international voyages which are dealt with in the remainder of
this section or short international voyages, which are dealt with in 9 1 1.5.

11.4. I International voyages
The factor of subdivision depends on the length of the ship and its Criterion of
Service numeral. There are three classes based on length:
(i) L (metres) = or < 79
(ii) 79 < L (metres) < 131
(iii) L (metres) 2 13 1

The length criterion is based on two factors A and B related to length as follows:
58.2 30.3
A=- + 0.18 and B=- + 0.18
L-60 L-42

(L = 131 m or more) (L = 79 mor more)
A corresponds to a ship which is primarily a cargo carrier and has a C, value
of 23 or less (F =A for C, = 23).
ForL= 131 m, A = 1.00
B corresponds to a ship which is primarily a passenger carrier and has a C,
value of 123 or more (F = B for C, = 123).

For L = 79 m, B = 1.00
For L = 131 m, B = 0.52.
Criterion of Service Numeral: Interpolation between A and B is carried out by the
Criterion of Service Numeral (C,) which provides a measurement of the extent to
which the ship is devoted to the carriage of passengers. There are two alternative
formulae for C,.