A Guide to Dry Bulk Operations: monitoring loaded voyage cargo

Some cargoes require little monitoring during the loaded sea passage, but others should be monitored closely. Alumina and salt do not require much monitoring from ship’s staff, but coal should be monitored daily. Failure to monitor when required can have catastrophic consequences and may even result in the loss of the vessel. 

 

The issue: sources of information  

As more is learned about cargo behaviours, the requirements for monitoring are likely to change. The IMSBC is updated every two years, so take care always to have the most up-to-date information from:  

• The individual schedule in the IMSBC Code 
• Shipper information 
• Loss prevention bulletins  
• IMO circulars from the Sub-Committee on Carriage of Cargoes and Containers (CCC) 

• Shipowner’s or manager’s past experience 
• Informal sources including ship’s staff, based on past experience. 

Occasionally, a bulk cargo is not listed in the IMSBC, yet may present hazards. In such cases, special care must be taken. 

At the time of writing more than 270 types of bulk cargoes are listed in Appendix 1 of IMSBC. Some precautions and procedures apply to a range of cargoes. However, many cargoes have specific requirements and need to be monitored in specific ways during the loaded passage. It is prudent, therefore, to follow all the precautions and directives laid down in the code and other supplementary information.  

The first step is to identify the cargo’s bulk cargo shipping name (BSCN) and its IMSBC group.  

As the voyage progresses, the moisture content of the cargo may change substantially from that declared at the load port. It may reach an alarming level, exceeding the transportable moisture limit (TML). This can occur with nickel ore and similar cargoes; and in the worst case may cause the vessel to capsize. Liquefaction during the voyage was identified as the probable cause of the sinking of both Vinalines Queen in 2012, carrying nickel ore, and Bulk Jupiter in 2015, carrying bauxite. Measures must also be taken to prevent water or other liquids from entering the cargo space during the voyage.  

IMO and P&I clubs frequently issue guidelines and share experiences of these critical cargoes. It is prudent to revisit this advice regularly, even if the ship has loaded a particular cargo recently, because the nature of the cargo and the conditions at the load port may well have changed since then. For example, the properties of each shipment of bauxite can be different based on the location of the mine, the type of bauxite and the terrain of the region where it was mined.  

It is scarcely believable, but in some ports, it is common for terminals to load coal while stockpiles are on fire. However, attempting to oppose this practice without sufficient evidence and owner’s support can result in the terminal threatening severe action against the Master.  

For some cargoes, such as coal, IMSBC requires hold bilges to be regularly pH-tested to avoid accumulation of acids on the hold top and in the bilges. pH is a scale in which water is neutral, with a property of 7. A pH of less than 7 indicates acidity – sulphuric acid has a pH of between 2 and 3 – while base solutions have a pH of more than 7. The easiest way to measure the pH of hold bilge water is to use pH paper (also called litmus paper), supplied in bundles of 50s and 100s. Acids will turn blue litmus paper red, while bases will turn red litmus blue.  

The temperature of coal cargo must also be monitored to ensure that it does not go above 55˚C. To test it, a thermometer on a thin rope should be lowered into the cargo hold through specially constructed temperature measuring pipes. These should have holes at regular intervals and reach almost to the bottom of the cargo hold.  

 

Case study one: COPRA (dry) 

On discharge of a shipment of dried coconut kernels (COPRA (dry) UN 1363) the shipper asked the ship’s staff for records of the temperature checks taken during the loaded passage. They were unable to do so, as no temperature checks had been carried out.  

 

Lessons learned 

IMSBC requires temperature to be measured and recorded regularly during the voyage for this cargo to monitor self-heating. 

In addition, when monitoring cargoes, the word ‘regular’ is often mentioned in the IMSBC Code. Most courts interpret ‘regular’ to mean daily, although some companies take it to be twice a day depending on the cargo. If the ship’s staff cannot carry out these checks, perhaps due to bad weather, this should be recorded in the deck logbook  for example:   

“Today it was not possible to carry out gas measurements for the coal cargo loaded in holds one and two as the vessel was shipping heavy seas forward all over due to rough seas and heavy swell.” 

For more detailed records, use the company’s recording sheet. Most companies have separate coal cargo monitoring sheets. If your company does not have a prescribed format, a simple Excel sheet is sufficient, though handwritten records are usually valued more highly than computer-generated files.  

At the end of the voyage it is good practice to attach these forms to the deck logbook for that month. Copies of the forms should be sent to the shipowner or manager. This aids retrieval if a query arises later. 

 

Case study two: ferrophosphorus 

Never enter a cargo hold loaded with bulk cargo as the risks are simply too high. Every loaded cargo hold should be considered an enclosed space, with the additional danger of cargo shift and injury if a person falls in it. 

A vessel sailed to pick up a cargo of ferrophosphorus at a remote port 20 days distant, stopping en route to take on additional bunkers and provisions. Two days before arriving at the load port the chief officer noticed that IMSBC required measurement of phosphine gas during the loaded passage. Delivery of the detector took two weeks at premium cost as there were no local ship suppliers. This was escalated to the shipowner and resulted in loss of reputation for the ship manager and ship’s staff. 

 

Lessons learned 

All ship’s staff should check IMSBC requirements as soon a new cargo is known. Requisition detectors or special equipment immediately, as delivery may take time. IMSBC is amended every two years, so even if you have carried a particular cargo before, requirements may have changed.  

 

Cargo-specific risk mitigation measures 

If there is a risk of fire or explosion, depending on the type of cargo, ventilate cargo holds and enclosed spaces adjacent to the holds. Ventilators may need to be explosion-proof. The atmosphere in cargo holds and enclosed spaces adjacent may also need to be monitored with an appropriate gas detector. However, these too can be cargo-specific; some cargoes can benefit from ventilation, while for others it can increase the danger. 

Toxic gas risk may be mitigated by using natural or forced mechanical ventilation, depending on the type of cargo and the properties of the gas (whether or not it creates an explosive atmosphere). The cargo hold atmosphere will also need monitoring. 

 

Case study three: direct reduced iron (A) briquettes, hot-moulded 

At the first discharge port, PSC inspectors asked the Master of a vessel carrying this cargo for the onboard hydrogen gas detector. The ship had a combined CO, H2S, methane and oxygen gas detector, but no hydrogen detector. The vessel was detained for not complying with IMSBC requirements and endangering the lives of those on board. 

 

Lessons learned 

If the ship’s staff had checked the IMSBC they could have asked the shipper to provide a hydrogen detector with the code specification. For this cargo, IMSBC requires cargo space temperature and hydrogen gas concentrations to be recorded and records kept for two years. 

Ultimately, it is important to treat each loading as if it were the first time at that port with that cargo for all officers and crew on board. This will ensure the utmost attention to detail and prevent complacency when it comes to monitoring cargo.  

 

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