A scullion was basically a dishwasher. They might have had other menial kitchen duties from time to time, but the catering operation was on such a large scale that dishwashing in itself was very much a full-time job.
>>but the catering operation was on such a large scale that dishwashing in itself was very much a full-time job.<<
There's an understatement and a half. I did deep sink duty on an aircraft carrier when I was but a humble seaman and this was one of those jobs that started as soon as you got in and was still there to be done twelve hours later when you got off. (Your relief took up where you left off.)
Much the same applied to the scullary which did the trays and the silverware and which was still busy long after the meal hours were over with. Fortunately, they had machines to do most of the dirty work.
The Deep Sink wasn't so lucky. Given that we did pots, pans, galley utensils, and huge baking pans, we had to scrub the grime off by hand. Fortunately, we had gloves as that water was HOT!!!!!