5.34 TANK INSPECTION AND THE DRY CERTIFICATE

When all cargo has been discharged and the tanks and pipelines stripped to the best of the ship and crew's ability, the chief officer must request a tank inspection by the terminal representative and the independent petroleum inspector.
If local or terminal regulations indicate that the tanks must be closed gauged at the completion of the discharge, then the IGS pressure must be maintained and the tanks will be measured using the portable ullaging device. If any measurable liquid is indicated in a cargo tank, it must also be measured for free water.
If open inspection is acceptable and requested by the terminal or the independent inspector, then the IGS pressure must be reduced to the point where the tanks can be opened for inspection. Only one cargo tank at a time should be opened and the inspection hatch should be closed and dogged immediately after the tank bottom has been sighted.
Some owners/charterer's direct the chief officer to obtain the signatures of the terminal representative and the petroleum inspector on a 'dry tank(s) certificate' after this inspection. The chief officer is unlikely to succeed in this endeavour. The inspectors will normally refuse to sign. This is understandable since the tanks are not really 'dry' within the definition of 'free from water or liquid' and it is unreasonable to ask an independent inspector to indicate that they are.
It would be better to request that the inspector sign a document indicating that there is 'no pumpable cargo remaining on board', as that is really the objective of the inspection.
The discrimination between pumpable and un-pumpable ROB must be based on a knowledge of the trim of the ship and the elevation of the tank suction bellmouth above the tank bottom. See section 5.35.
If the shore terminal or independent inspector will not provide a certificate of complete discharge of the cargo, then the ship should provide its own certificate, signed by the chief officer to attest that all pumpable cargo has been delivered to the receivers. This certificate may be noted with a comment that the terminal representative has refused to sign the document on the basis that he is not authorised (or is prohibited), to do so.