1.1.2 These tolerances
are suitable when deformation is gradual and local in extent. Where
distortion/deformation is sharp-edged, then consideration should be
given to an insert being fitted.
1.1.3 It is important
to determine the origin of the distortion or deformation. It may be
from contact (local dish or dent, sometimes sharp edged), large lateral
pressure (multiple dishing over a large area) or large in-plane load
(buckling). In all cases, the possible cause of the distortion is
to be reported.
1.1.4 Where a distortion
of structure has taken place that is contained within one frame space
or longitudinal space and is less than the allowance given in Table 14.1.1 Maximum permissible
distortion, then a suitable memorandum
item should be raised.
Table 14.1.1 Maximum permissible
distortion
Area of
structure
|
Maximum permissible distortion
|
| Shells & Decks
|
Plating between stiffeners
|
Stiffeners
|
| Whichever is the greater of:
(a)
Frame spacing/100
(b) 6t
(c) 35 mm
|
Frame
spacing/100
|
| Bulkheads
|
Whichever is the smaller
of:
6t
35 mm
|
35 mm
between
decks
|
All other
structures
|
Whichever is the smaller:
45
mm
8t
|
35 mm
between
support
structure
|
Note
|
t
|
= |
plate thickness in mm |
|
1.1.5 Where distortion
of structure has taken place which extends over more than a frame
space or longitudinal space, it is to be thoroughly examined internally
and provided the internal distortion is slight and the distortion
of shell or deck is less than the allowance in Table 14.1.1 Maximum permissible
distortion and gradual, then this may also be considered
to be a memorandum item. Where the distortion is extensive, consideration
should be given to the possibility of an underlying problem such as
corrosion, fracture or modification of structure or component.