– Continue to systematically carry out and record ‘Can Tests’ as described above.


– Restrict the ingress of water and not load during periods of rainfall.


– Make sure that the hatch covers of all non-working holds are kept shut.


– Ensure that, if the cargo is being loaded from barges, the barges are adequately covered during periods of precipitation and water ingress. If this is not the case, the master should not accept any cargo from these barges unless the moisture content has been re-established.


– If the vessel encounters prolonged periods of precipitation during the loading period, request check tests to ensure that the MC of the cargo is still less than its TML.


– Prior to completion of loading, ensure that the cargo is reasonably trimmed (as per dry bulk cargo good practice).


– On completion of loading, ensure that the hatch covers are closed and secured as required.


If during loading the master has reason to suspect that the MC is in excess of the TML, he/she should stop loading the cargo and inform the owners. The master may issue a ‘Letter of Protest’ and seek further advice from the P&I Club.


During the voyage


Monitor the cargo holds regularly to check for any sign of accumulation of free water in the cargo. Although these inspections may not provide a true representation of the cargo condition, they may provide an indication of how the cargo has behaved since it was loaded. However, this should only be carried out if it is safe to enter the holds, as mineral cargoes tend to deplete oxygen levels.


If it is not already part of the ship’s routine, sound the cargo hold bilges on a daily basis. Although


free water is expected to drain it can hold the moisture towards the bottom of the hold and develop a wet base.


If necessary, consider ventilation of cargo as and when appropriate. This will depend on the advice contained in the IMSBC Code for that particular cargo loaded. Monitor the vessel’s motion, in particular the rolling period. A change in the rolling period may provide a warning of a reduction in the vessel’s GM.


If the master or owner has any reason to suspect that the cargo liquefaction is or may be occurring, they should immediately:


– Contact their P&I Club;


– Contact the nearest coastal state authority;


– Consider heading to the nearest port or place of refuge;


– Consider measures to reduce the vessel’s vibration/motion.


Key facts about cargo liquefaction


Cargo liquefaction may occur without additional water content (e.g. from rainwater) if the inherent moisture content is already too high, yet undetected by improper checks/tests, agitation alone will cause liquefaction to happen.


– Space between particles reduces – Air is expelled – Water pushes particles apart – Loss of shear strength – Solid cargo becomes liquid – Centre of gravity shifts – Free surface effect – Ships may capsize


Read the booklet in pdf format at https://bit.ly/2TfBInP.


88 | The Report • December 2020 • Issue 94


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