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3.5 TANK INSPECTION AND THE 'DRY' CERTIFICATE
Responsibility for ensuring that cargo tanks are suitably prepared
to carry the nominated cargo rests with the master. He is responsible
for putting standard procedures in place to prepare the tanks and to
complete the necessary documentation of preparations and inspections.
3.5.1 Tank inspection
Before loading, tanks should be inspected by a ship's officer, shore
terminal representative and (probably), by independent petroleum inspector
(who may represent the buyer and/or seller of the oil). The following
levels of inspection may be completed:
On inerted ships - the remote gauges (normally in the CCR), are checked
to see that they indicate all cargo tanks are empty.
On inerted ships - the tape and bob, or portable probe is used to verify
the innage of all tank bottom contents and its measurements are used
to determine the quantity of same if any measurable product is found.
On non-inerted product ships - tank hatches or ullage ports may be opened
and the tank bottoms are sighted to verify that the tank is 'dry' (no
liquid can be seen), below the hatch or ullage port.
On non-inerted product ships - the tanks may be ventilated and entered
to verify that they are completely free of liquid, scale, sediment and/or
clingage and that the coatings are in good condition. Tank entry for
inspection at the loading terminal requires implementation of the full
tank entry procedure as described in Section 2.15
of this handbook. After in-tank inspection, ensure that all openings
are suitably closed (as indicated in section 2.17).
If pipelines have been drained, the fact that they are empty should
be demonstrated to the inspectors.
3.5.2 Inspection certificate or on board quantity
(OBQ) certificate
When the tank inspection has been completed, the members of the inspection
party should sign an 'inspection certificate' indicating the date, port,
name of the ship and which tanks have been inspected. The certificate
should indicate that the tanks have been found 'suitable for the loading
of cargo' and indicate the name and grade of the cargo to be
loaded. It was previously customary to request independent inspectors
signature on a 'dry certificate'. Since cargo tanks are seldom completely
dry, independent inspectors correctly refuse to sign such documents.
If the master insists that the 'dry certificate' form be used, he will
probably not obtain the independent inspector's signature. It is better
to obtain what is actually needed, certification that the tanks are
suitable for loading the nominated cargo, than to have no independent
certification at all.
If pipelines have been demonstrated to be empty, that fact should also
appear on the certificate.
Request that shore terminal and independent inspectors print their full
names and the names of the organisations they represent below their
signatures. The inspecting ship's officer or chief officer should also
sign the certificate.
After tank inspection is complete, make a logbook entry indicating the
time of completion, names of the inspectors and the fact that tanks
were found suitable for loading. If the independent inspector refuses
to issue or sign a 'suitably clean' certificate, then one should be
prepared and signed the chief officer and the master.
3.5.3 Measuring and sampling on-board cargo
Before loading, all material in cargo and slop tanks must be measured
and sampled. On board quantity (OBQ), of cargo and slop tank contents
must be ullaged, water cut and sampled, with the samples properly labelled
and sealed by the independent petroleum inspector.
The quantity of material in the ship's pipelines must be declared by
the chief officer. The independent inspector will not certify the pipelines
amounts, but may indicate on his report that the loading lines are 'said
to contain' an amount of cargo indicated by the chief officer. An OBQ
certificate should be prepared and signed by the inspector.
The master should note any protest he has concerning the independent
inspector's or shore terminal representative's recording of the OBQ
quantities/qualities.
The quantity of sediment in cargo tanks is often the cause for some
contention. Any mis-measurement of sediment can be minimised by ensuring
that the ship has available suitable measurement equipment (a pointed
bob) and accurate total depth measurements for each and every
tank ullage point. The pointed bob can then be trusted to accurately
reflect the depth of sediment provided it is seen to strike bottom at
the indicated total depth of the applicable ullage point. For accurate
sediment measurement, the tank should be sounded at four or more points.
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