What are the preparations to be made prior to loading cargoes?
Following the discharge of any bulk cargo after a voyage, the holds are to be properly swept before any water washing takes place. This process avoids any prior residue building up and also avoids any contamination, which includes cleaning the hatch coamings, drains and frames.
After the sweeping and sea-water hold washing, the surfaces must then be washed with fresh-water. The reason this is carried out is to rid the hold of salt deposits which may rust the steelwork and fittings and ultimately ruin any cargo.
After the water washing, the hold must be dried thoroughly before the introduction of any bulk cargo. To speed-up this drying time, the ships own ventilation system should be used.
Fumigation of holds
About the carriage of grain, the holds may need to be fumigated to kill any insect/pest problem that may have been present.
Finally, to ensure the hold preparation process is to a satisfactory standard, the Chief Officer will inspect the holds before loading.
Hold Integrity Testing
It’s important to ensure the weathertight integrity of hatch-covers to avoid leakages enroute, which could potentially destroy cargoes. Testing methods as below :
The hatch cover runs are initially chalked before the hatches are closed and then reopened. The compressed rubber seals are then checked to ensure the chalk mark is present, which should run continuously, but any gaps in the chalk marking indicate a weakness of compression.
Apply a powerful jet of water around a closed hatch cover joint. Afterward, it can be seen if any water ingress took place, noting the location, as this indicates the area of weakness.
The test involves placing an electronic signal generator inside a closed cargo hold. A sensor is then passed around the outside of the closed hold cover. Readings taken by the sensor indicate points of low compression or potential points of leakage. Ultrasonic testing is the most accurate method.