Wikipedia
A pumpman is an unlicensed member of the Deck Department of a merchant ship. Pumpmen are found almost exclusively on tankers, and on oil tankers in particular. Variations on the title can include chief pumpman, QMED/pumpman, and second pumpman.
A pumpman performs all work necessary for the safe and proper operation of the liquid cargo transfer system. This includes but is not limited to: liquid cargo transfer pumps, liquid cargo stripping pumps, liquid cargo coalesces and separators, strainers, filters, associated piping, valves, fittings, and deck machinery directly related to the transfer of liquid cargo.
Usage examples of "pumpman".
The service at the Parrot was not all that was required of the men forming the gun crew, for each was also a first or second boarder, a pumpman, or something else, and to each number one or two weapons were assigned, as musket and pike, sword and pistol, battle-axe.
Besides serving to re-enforce the other two divisions when absolutely necessary, it is also to re-enforce either the Firemen or the Pumpmen in cases of need.
When Pumpmen are sufficiently numerous to admit of working the pumps with one-half their force, they should compose two divisions, to be called 1st and 2d Pumpmen.
Those for Firemen, Sail-trimmers, and Pumpmen to have each a frog for the battle-axe.
Here behind the control console where the pumpman now sat, a visual display board, nine feet wide and four feet tall, occupied the wall.