The STCW II/1 - Office in Charge of a Navigational Watch (OICNW) 500 GT or More Operational Level assists the Chief Engineer and performs ship maintenance, engine maintenance, machinery repairs, and fueling. They are also responsible for electrical, sewage treatment, lube oil, bilge, and oily water separation systems, and stand a watch. Their duties depend upon the type of ship or vessel and arrangement of the engine department.