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, 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:
.1 Ballast tanks: To the same extent as previous
.2 Cargo tanks: Two combined cargo/ballast tanks.
The extent of survey should be based on the record of the previous
renewal survey, and repair history of the tanks.
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 may be specially considered by
4.3.5 Extent of thickness measurement
The minimum requirements for thickness measurements at the intermediate
survey are areas found to be suspect areas at the previous renewal
survey. Where substantial corrosion is found, the extent of the thickness
measurements should be increased in accordance with the requirements
of annex 4