Bulk Cargo is cargo that is transported unpackaged and in large quantities. Generally, commodities such as grain, coal or oil are known as bulk shipments. In the case where they are loaded separately in bags, boxes or drums, this is defined as break-bulk.
Bulk cargo is prone to more types of losses than containerised shipments, and the values are much higher because of the possibility of 'spread' or ease to transit further damage. Most common types of damage are:
Condensation and Sweat
Bulk cargoes are generally hydroscopic, so shipments tend to be susceptible to sweat or condensation if adequate ventilation has not been provided.
To understand how condensation and sweat forms is to appreciate that air retains moisture as temperature increases and vice versa. As temperature decreases the air becomes saturated and unable to retain all its moisture. This leads to condensation and sweat, and can result in various types:
Ship's Sweat: This generally occurs from warmer to colder climate.
Cargo Sweat: This generally occurs from colder to warmer climate
Ensure proper ventilation but it is important to follow some guidelines:
Do not ventilate in high humidity environments such as rain or fog.
Ventilate when atmospheric temperatures are rising.
Ventilate if atmospheric loading temperature much colder of hotter than cargo.
Caking, Heating and/or Moisture Migration
A common problem with bulk cargo is standing still is generally not good for it but the whole concept of shipping entails long periods of static. Same as sweating but hygroscopic cargoes give up moisture, but this escalates the problem. The cargo will try to keep a equilibrium so the warmer cargo will seek to give up moisture to the cooler region and over time this moisture migration will lead to heating/caking or even spontaneous combustion.
Ensure proper ventilation but cargo must not be stagnant for too long.
An inevitable problem with bulk cargo because often the consumable nature and the volumes. Adds to loss of weight, condensation, heating, contamination or just depreciation. Cargo is often fumigated but whilst claims are often made against carriers these are normally refuted.
Ensure proper fumigation but important to:
Fumigate as close as possible to sailing and not days/weeks before.
After fumigation do not place close to non-fumigated cargo.
Inspect once onboard the vessel and/or do not load if already visible.
This generally involves cargo such a logs or steel roll bars. Whilst sensitive to water they are tend not to be hydroscopic, but stability is a much greater concern.
Any breakings on lashing or shift in stowage can have a deadly effect on the stability of the vessel that could eventually cause its sinking. This occurs when the weight distribution has been shifted resulting in the vessel leaning more on a certain angle. With each further roll/pitch of the vessel these stresses increase. Further cargo shifts can eventually cause the vessel to capsize.
At best this may just seriously damage the vessel without harming any of the crew or personnel. Very special care needs to be taken on the stowage of the logs. Log carriers use by specialised personnel to conduct this process. The same applies with steel bars or any bulk cargo for that matter, which unfortunately still is a cause of lost vessels each year.