Load on Top. In the TANKERVOY 87 voyage charterparty the “Load On Top” system and procedure is briefly described in the clauses dealing with disposal of residues after cleaning tanks.
It states, among other matters, that the owners must collect the washings and any draining from the previous cargo into a suitable tank (which is called the “slop tank”) and after maximum separation of free water and oil, discharge the bulk of the free water overboard as permitted by MARPOL 73/78 (the International Convention for the Prevention of Marine Pollution from Ships). The charterers must be notified of the amounts of oil and free water remaining on board. The charterers can give instructions as to how the collected washings are to be dealt with, perhaps discharged ashore before loading. Alternatively, charterers may require that the new cargo be loaded on top of the collected washings, which are then discharged with the loaded cargo. Freight may then be payable on the collected washings as well as on the loaded cargo. Freight on cargo, which is not loaded at the loading port, may be justifiable by the charterer because he will probably obtain a large quantity of oil in exchange.
The Load on Top system is usually used for crude oil tankers. After frequent cleaning of tanks, pumps and pipelines, considerable “slops” accumulate on boar. Some refineries can process slops after separation of the oil and any water is done in shore tanks. Some charterers may not permit cargo to be loaded on top of residues of previous cargoes, especially if the new cargo can be contaminated.