Fire
Fires account for around 25% of all losses in the containership fleet, and around 10% of the fatalities. Although most fires start in engine rooms and are contained by engine room carbon dioxide systems, hold fires tend to spread and cause more widespread damage. In many situations it is the variety of cargoes being carried that make control of hold fire difficult. Hazards are increased due to the difficulty of access once a fire has initiated.
Liquefaction
Liquefaction results in a flow state to develop. This permits the cargo to slide and shift in one direction thus creating free surface effect and reducing the GM thereby reducing stability. Shippers declaration should be thoroughly examined by the chief officer before loading any bulk cargo.
Cargoes that are at risk of liquefaction are those containing at least some fine particles and some moisture, although they need not be visibly wet in appearance. The most widely known cargoes with this hazard are mineral concentrates, although many other cargoes can also liquefy, such as fluorspar, certain grades of coal, pyrites, millscale, sinter/pellet feed, etc.
Although they often look dry in appearance at the time of loading, these cargoes contain moisture in between the particles. At the time of loading, the cargoes are usually in their solid state, where the particles are in direct contact with each other and, therefore, there is physical strength of resistance to shear strains. During ocean transport, cargoes are exposed to agitation in the form of engine vibrations, ship’s motions and wave impact, resulting in compaction of the cargo. This leads to a reduction of the spaces between the particles. If compaction is such that there is more water inside the cargo than there are spaces between the particles, the water pressure inside the cargo can rise sharply and press the particles apart.
Cargo liquefaction will not occur if the cargo contains a sufficiently low inherent moisture content and sufficiently high interstitial air that, even in its most compacted state, there are still sufficient interstitial spaces to accommodate all of the moisture so that the increase in water pressure is inhibited
