A pro-active approach to cargo sampling on tankers can
potentially save millions of dollars in claims and prevent delays to the
vessel. In this Insight, insurance and P&I club Gard looks at some critical
aspects of cargo sampling on tankers. Disputes relating to ‘off-spec’ or
contaminated liquid cargoes are a recurring problem and ship owners may have no
independent evidence as to the cause of an alleged cargo contamination.
The source of the problem could be in the shore tank at the
load port, in the shore pipeline during loading or on board the vessel itself.
The cargo could even have been manufactured out of specification prior to
delivery to the terminal for shipment.
However, if the cargo is found to be ‘off-spec’ when the
vessel arrives at the discharge port and there is no evidence of contamination from
the load port, the vessel could be faced with a claim, even if the vessel is
not at fault. Samples drawn at the load port and retained on board showing that
the condition of the cargo has not changed between loading and discharge
provide the best defense against cargo claims. It is therefore important that
ship owners and operators implement proper procedures for taking, and
retaining, own (duplicate) samples of all cargoes loaded on the vessel and
train their crew in how to perform the sampling process. For example, an
experienced officer may be able to identify a poor-quality sample by visual
inspection alone, and early intervention may prevent an expensive claim arising
later.
Case Study
Although substantial resources are used on board vessels in
the preparation and cleaning of tanks and lines prior to loading, we see that
samples are frequently not taken by the vessel at the start of loading.
Alternatively, where samples are taken, they are not taken following the proper
procedure or are discarded for one reason or another before they can be analyzed.
In a recent Gard case, a chemical carrier arrived at a
terminal with its cargo tanks and lines cleaned and ready for loading.
The vessel was inspected upon arrival and found to be
suitable for the nominated cargo. No manifold samples were taken at the
commencement of loading, but first foot samples were taken from the designated
tanks that were being loaded.
Upon analysis of the first foot samples, the cargo was found
to be ‘off-spec’ resulting in stoppages and delays on the vessel’s account for
further tank cleaning. The vessel was held responsible for contaminating the
cargo and the cargo in the vessel’s tank was pumped back ashore and the vessel
was instructed to leave the terminal to clean her cargo tanks and lines.
She returned to the terminal following cleaning operations
and loading was resumed. On this occasion, manifold samples were taken and
analysed and everything found to be in order. However, upon detailed analysis
of the sample of the contaminated cargo, the cause of the contamination was
suspected to be from the remains of the previous cargo in the shore tanks and
lines. Given that there were no manifold samples on the first occasion, there
was no way for the vessel to prove that the cargo received on the first
occasion may have been contaminated prior loading. Protecting interestsThe
manifold - The transfer of custody of the cargo from another vessel or the
terminal to the vessel, and vice versa, normally takes place when the cargo
passes the vessel’s manifold. A manifold sample taken at the start of loading
and discharge can, in principle, determine who is responsible for the
contamination of a cargo. It should be noted that manifold samples should be
taken outboard of the manifold valve. During this process, the loading rate
should be very low, preferably by gravity.
In some Gard cases, even where a manifold sample had been
taken at the start of loading, samples have been known to have been disposed of
by the crew if they do not appear to be of the expected quality. A new sample
is then drawn once the cargo quality appears as expected, and becomes the
manifold sample ‘on record’, as having been taken by the ship at first loading.
Thus, the only evidence available in this instance indicates
that sound cargo was loaded and the evidence showing that the cargo had been
contaminated ashore is lost.
While this practice appears to be counterintuitive, it is
nonetheless, prevalent. First foot samples - These should be taken to confirm
that the vessel’s systems and pipes are clean. This is particularly important
where sensitive and/or expensive cargoes are loaded to reduce the risks
associated with contamination of the entire cargo parcel. Tank samples- Taking
a final tank sample after completion of loading and prior to commencement of
discharge will enable the vessel to determine the cause of any potential
contamination on board. It can also be useful for the officer in charge to
request specimens of samples taken by the terminal’s surveyor at the terminal’s
manifold as well as samples from the shore tank and shore line.
If the quality of the cargo samples from the ship and shore
appear to be different, loading should be ceased for further investigation.
Recommendations
To ensure the best possible defense of a cargo claim against
the vessel, it is recommended that ship owners create awareness among the crew
of the problems related to improper sampling and have in place written procedures
describing the sampling process in detail. An improper sampling method can
result in a poor-quality sample which is not necessarily representative of the
cargo itself.
The procedures should include and emphasize the following
points:
• Involvement of vessels’ crew. The crew should participate
in the taking of cargo samples, both during loading and discharge, and should
be competent in checking and verifying the quality of the samples taken. The
Chief Officer should preferably be involved in all cargo sampling whether it is
taking samples for the vessel or for the charterers.
• Independent cargo samples to be taken by the vessels’
crew. As a minimum, the crew should, for each grade of the cargo, take:
• Manifold samples, taken at a vessel’s manifold at the
start of loading, preferably with the manifold valve in a closed position. Spot
checks should be carried out at the manifold during loading whenever
practicable, eg after shore stops and/or change of shore tanks.
• Pump stack samples, if taken by a surveyor the vessel
should take own/duplicate samples.
• First foot samples, taken from the cargo tanks once cargo
level reached the first foot in the tank(s).
• Final tank samples, taken from the cargo tanks after
completion of loading.
• Cargo tank samples prior to commencement of discharge.
• The importance of the manifold sample often referred to as
the ‘million-dollar sample’. Where a proper sample of the first products loaded
has been drawn and retained on board, any uncertainty about the quality of the
cargo at the time of loading can usually be clarified at relatively low cost.
Vessel procedures should therefore be specifically formulated to avoid any
misunderstandings when it comes to ensuring that this manifold sample is never
disposed of, regardless of its apparent quality.
Handling of
samples
• Always flush the sampling point prior to drawing a sample.
• Always use clean and appropriate sampling equipment and
properly label, seal and store the samples in designated areas
• The labelling should always state where, what type and
when the sample was drawn, eg ‘manifold at commencement of loading’ or ‘final
tank sample drawn in the middle of cargo tank 4P’.
• Ensure there are sufficient sample amounts for retesting
if necessary.
• For sample retention, we recommend members and clients
have a clear policy taking into consideration the storage space, the vessel’s
schedule and the number of grades loaded for each voyage. Samples should be
retained for at least three months after the completion of discharge. If the
vessel has received complaints during a voyage the samples should be retained
for longer if possible, or ask your insurer if the samples can be disposed of.
• Recordings should be made in the cargo log-book to ensure
traceability of samples taken.
• Sample bottles should, as far as possible, be suitable for
the cargo in question. For example, use amber coloured glass bottles for UV
sensitive cargo to prevent deterioration due to the effects of UV lights.
• For cargo that is oxygen sensitive the bottles should be
purged with nitrogen prior to sampling.
• Sample report: On completion of sampling, a sample report
should be produced by the vessel listing the unique identifier number of each
sample retained on board and of the samples given to the charterers’ surveyor.
The sample report should be jointly signed by the vessel’s Master, or his
representative, and the charterers’ surveyor. Ship owners and operators should
instruct their officers on board that whenever they are in doubt as to the
apparent quality of a liquid bulk cargo, they should seek expert advice and
have any samples analyzed at the loading port.
