Tank cleaning
Meaning
Tank cleaning is washing a tanker's cargo tanks between cargoes so the next cargo is not contaminated, especially when switching grades.
Tank cleaning explained
Product tankers clean frequently, for example when moving from a dirty cargo such as fuel oil to a clean one such as jet fuel, which can take several days and needs the right chemicals and slop handling. Crude tankers clean less often.
Time and cost of cleaning, and the standard required, are agreed in the recap, often with an inspection before loading.
Related terms
Last three cargoes
Last three cargoes (L3C) are the grades a tanker carried on its three previous voyages, checked by charterers to judge contamination risk.
Clean tanker
A clean tanker carries refined clean products such as gasoline, naphtha, jet fuel and diesel, usually with coated tanks to protect cargo quality.
Dirty tanker
A dirty tanker carries crude oil or dirty petroleum products such as fuel oil, which can't follow straight into a clean product without major cleaning.
Slops
Slops are the oily water mixtures from tank washing and cargo residues, collected in a tanker's slop tanks for disposal or for loading on top.