4.2.1.1 For spaces used for salt water ballast,
an overall survey of representative spaces selected by the surveyor
should be carried out. If such inspections reveal no visible structural
defects, the examination may be limited to a verification that the
protective coating remains efficient.
4.2.1.2 Where POOR coating condition, corrosion
or other defects are found in salt water ballast spaces or where protective
coating was not applied from the time of construction, the examination
should be extended to other ballast spaces of the same type.
4.2.1.3 In salt water ballast spaces other than
double bottom tanks, where a protective coating is found in POOR condition
and it is not renewed, or where soft coating has been applied, or
where a protective coating was not applied from the time of construction,
the tanks in question should be examined and thickness measurements
carried out as considered necessary at annual intervals. When such
breakdown of coating is found in salt water ballast double bottom
tanks, where a soft coating has been applied, or where a coating has
not been applied, the tanks in question should be examined at annual
intervals. When considered necessary by the surveyor, or where extensive
corrosion exists, thickness measurements should be carried out.
4.2.1.4 In addition to the above requirements,
areas found to be suspect areas at the previous renewal survey should
be overall and close-up surveyed.