Tanker vessels are not dedicated to one single type of cargo throughout their lives and they usually carry a different type of cargo at any subsequent voyage. On this basis they are required to perform accurate and complex cargo tanks cleaning procedures which vary according to the nature of the cargo just carried and the nature of the next cargo to be carried.
Prior to loading any cargo, all tanker vessels must pass a cargo tank cleanliness inspection performed by the loading port cargo surveyor appointed by the shippers. On this basis a vessel will be allowed to load only if this cargo surveyor is satisfied with the cleanliness conditions. If he is not, the vessel will be rejected and sent to anchorage for further cargo tank cleaning thus wasting various days with all the relevant costs such as time lost, mooring/unmooring, pilot and others.
Most of these cargo tank cleaning operations require the support of chemical products and a knowledge of chemistry which is not available among the personnel on board. On these basis CMC personnel is frequently joining vessels during short navigations in order to arrange and supervise the cargo tanks cleaning operations in order for the vessel to arrive at the next loading port with her cargo tanks in outstanding cleanliness conditions.