4.3.1 The requirements of 4.2 apply.
4.3.2 An overall survey of at least two representative
cargo tanks should be carried out.
4.3.3 For ballast tanks, where fitted, an overall
survey of all such tanks should be carried out. If such survey reveals
no visible structural defects, the survey may be limited to a verification
that the protective coatings remain efficient.
4.3.4 Extent of close-up survey
|to the same extent as previous
|the extent of survey should be
based on the record of the previous renewal survey and repair history of
the tanks, and be applied to two cargo tanks after the second renewal
The minimum requirements of close-up
surveys are given in annex 5. The extent of close-up surveys may be
extended as stated in 2.4.3. For areas in tanks where coatings are
found to be in GOOD condition, the extent of the close-up surveys
according to annex 5 may be specially considered by the Administration.
4.3.5 Extent of thickness measurements
The extent of thickness measurements is also given in annex
5. The minimum requirements for thickness measurements at the intermediate
survey are areas found to be suspect areas according to 1.2.7 at the
previous renewal survey. Where substantial corrosion as defined in
1.2.8 is found, the extent of the thickness measurements according
to annex 5 should be increased in accordance with the requirements
of annex 4.