TT Talk - Risky carriage
The Club was recently asked for its opinion on the carriage of single rough hewn blocks of marble in 20' dry units. It also appeared that the true mass of the cargo is generally estimated - frequently inaccurately - at values in excess of 20 tonnes. The loading operation was primitive. Some blocks were loaded directly onto the container floor. At best bearers up to a maximum of 6m long by 200mm square were inserted.
The following summarises the Club's advice and concerns:
- ·Cargo mass
Procedures should be put in place to establish the true mass of the cargo and container. At the very least this should be by calculation based on the actual size of the block, plus the tare mass of the container. Since there are measuring systems available that can be deployed in unsophisticated facilities, the Club recommended that the mass should be accurately established.
- · Spreading the load
The cargo mass in this trade has the capability of exceeding the structural limits of the container unit, in particular the floor. The 200mm square skids spread the load only slightly, but would be insufficient to support the load in the event of extreme dynamic forces potentially encountered in handling and transport. It was advised that the loaded mass be reduced to a level that is consistently within the structural tolerance.
- Cargo securing
The inability to secure the load to the skids or the container means that, again under extreme dynamic conditions, there is nothing to maintain the friction between block and skids, and skids and floor, to prevent this block breaking out of the unit. It might be better if the blocks could be carried on flatracks, supported on beams, and secured to the lashing points, which are generally stronger on such units.
- Risk exposure
The proposal exposes the carrier to the likelihood of container damage, at best stressing the components and giving rise to probable early failure. Further, there is considerable risk that the cargo will break through the container, particularly during lifting operations, giving rise to high potential exposures, such as damage to the ship, other cargo, damage to equipment and injury/fatality. Cargo movement in the container can also pose a major risk of accidents including overturning of trucks and chassis.
While the number of known accidents from this type of carriage are low, it is clearly a major accident waiting to happen. The likelihood of a substantial liability exposure is high. In the absence of strenuous mitigating action, the Club recommended that this trade is avoided.
TT Talk - Edition 139 (Chinese) (202 KB)