4 Intermediate survey

  4.1.1 Items that are additional to the requirements of the annual survey may be surveyed either at the second or third annual survey or between these surveys.

  4.1.2 The survey extent of cargo and ballast tanks dependent on the age of the ship is specified in 4.2, 4.3 and 4.4 and shown in annex 5.

  4.1.3 For weather decks, an examination as far as applicable of cargo, crude oil washing, bunker, ballast, steam and vent piping systems as well as vent masts and headers. If upon examination there is any doubt as to the condition of the piping, the piping may be required to be pressure tested, thickness measured or both.

  4.2.1 The requirements of 4.1.3 apply.

  4.2.2 For tanks used for salt-water ballast, an overall survey of representative tanks selected by the surveyor should be carried out. If the overall survey of salt-water ballast tanks reveals no visible structural defects, the examination may be limited to verification that the protective coatings remain efficient.

  4.2.3 Where POOR coating condition, corrosion or other defects are found in salt water ballast tanks or where a protective coating was not applied from the time of construction, the examination should be extended to other ballast tanks of the same type.

  4.2.4 In salt water ballast tanks where a protective coating is found in POOR condition and it is not renewed, 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.

  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

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.

 The requirements of the intermediate survey should be to the same extent as the previous renewal survey as required in 2 and 5.1. However, pressure testing of cargo and ballast tanks is not required unless deemed necessary by the attending surveyor.