A coal trimmer or trimmer is a position within the engineering department of a coal-fired steamship that involves all coal handling duties. Their main task is to ensure that coal is evenly distributed within a ship to ensure it remains trim in the water. Their efforts to control the fore-and-aft angle at which a ship floats is why they are called “trimmers”. Without proper management of the coal bunkers, ships could easily list due to uneven distribution of the coal.
The role of trimmers starts with the bunkering of coal, distributing it evenly within the bunkers, and then providing a consistent delivery of coal to the stoker or fireman working the vessel’s boilers.
Coal trimming was also a role based at the docks that involved levelling out the coal in a ship's hold to ensure that the ship was safe to travel. Coal was transported to the docks via railway wagons and the coal was tipped into the ship. As the coal was loaded into a hold of the ship it would form a conical pile. This was unsafe for the ship to sail in case the coal moved to one side causing the ship to list and roll.
Trimmers shovelled the coal out so that it was level and the ship was safe. It was a difficult job in dark and dangerous conditions.