Tank cleaning

Cleaning a tanker’s cargo tanks between cargoes to the standard the next grade requires, from a simple water wash to full clean for a sensitive product, often using fixed or portable tank-cleaning machines and, on crude carriers, crude oil washing. The operation must be controlled for the explosion risk (tanks kept inert), the slops generated (handled under MARPOL Annex I or II), and the time and cost it adds between fixtures. The cleanliness standard achieved decides which cargoes the ship can next carry.