Namely, the vessel had loaded two different cargoes of crude. The first parcel, consisting of Mondo Blend Crude Oil, was loaded in October 2017, and no free water was detected upon loading.

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The second parcel, being Cabinda Crude Oil, was loaded nine days later, with zero free water having been found. However, after the completion of loading 1,038 bbls of free water were detected through tank gauging with water finder paste. This amount would have been within the range stated in the Certificate of Quality. However, the vessel's Master issued a Letter of Protest, whereby he warned that more water may be found during the voyage. In any event, following from ship Total Calculated Volume and shore Gross Standard Volume, this water was loaded with the cargo.

The vessel then sailed to its first Chinese port for discharging the Cabinda Crude. During the voyage regular water dips were taken by the crew, showing the amount of free water having settled in the cargo tanks carrying Cabinda Crude to have increased drastically up to 6,703 bbls.

When the vessel arrived at its first discharge port at the end of November 2017, and during the joint ullage survey, gauging with water paste revealed only 1,166 bbls of free water.

After completion of discharge a measurement survey was carried out in the respective shore tanks and it revealed an amount of 29,948 bbls of free water.

Thereafter the vessel proceeded to its second Chinese discharge port to discharge the Mondo Blend parcel, and a joint ullage survey was carried out whereby gauging was performed with water finder paste, showing no reaction. Against the back-drop of the massive amounts of water found in the first discharge port, the parties decided to use a closed type portable water interface detector to verify the gauging result. The instrument detected  10,346 bbls of free water having settled underneath the Mondo Blend.

As a result, the receivers made substantial claims for net outturn cargo shortages in both discharge ports against the vessel.

In this case, the free water increase was caused by the fact that the cargo could retain free water in suspension for a longer period making it impossible to be detected shortly after loading.

In order to avoid similar cases, it is important for an operator to keep in mind that if ballast is to be discharged at the load port simultaneously to loading, it is recommended to ensure that representative samples of each type of ballast to be discharged are taken and sealed by cargo inspectors. If free water is found upon loading, lodging a Letter of Protest is important in any event, regardless of the content provided by the Certificate of Quality.

However, once confronted with a claim for net outturn cargo shortage because of excessive free water, it is crucial to be able to provide evidence showing the origin of the free water to be shore based.

Therefore, it is important to have samples retained of all free water having been found at different stages. In addition, top, middle and bottom or running samples should also be drawn from each tank enabling to ascertain what water was retained in suspension.