3.1 The surveyor should decide final extent and
location of thickness measurements after overall survey of representative
3.2 In case the owner prefers to commence the
thickness measurements prior to the overall survey, then the surveyor
should advise that the planned extent and locations of thickness measurements
are subject to confirmation during the overall survey. Based on findings,
the surveyor may require additional thickness measurements to be taken.
3.3 The surveyor should direct the gauging operation
by selecting locations such that readings taken represent, on average,
the condition of the structure for that area.
3.4 Thickness measurements taken mainly to evaluate
the extent of corrosion, which may affect the hull girder strength,
should be carried out in a systematic manner such that all longitudinal
structural members are gauged, as required.
3.5 Where thickness measurements indicate substantial
corrosion or wastage in excess of allowable diminution, the surveyor
should direct locations for additional thickness measurements in order
to delineate areas of substantial corrosion and to identify structural
members for repairs/renewals.
3.6 Thickness measurements of structures in areas
where close-up surveys are required should be carried out simultaneously
with close-up survey.