This drawing depicts Thames barges in the process of ‘shooting the bridge’. Rather than stopping to lower their masts before going under a bridge, experienced bargemen would lower their mast on the approach, using their momentum to carry them under and then raise the mast once they were through. Maintaining ‘way’ was key to the success of this operation and so it is likely that it would have been done at slack water or with a following tide. Although a foul tide would have offered greater manoeuvrability while coming under the bridge, it would have posed the risk of being swept back on to the bridge if the barge ran short of momentum.

In this scene, two barges are in the process of raising their masts having come under the bridge and a third, visible through the bridge arch, is lowering her mast in preparation for going under. Raising and lowering the mast was a relatively simple operation: it was winched up or down with the aid of the windlass as can be seen on the foredeck of the nearest barge where two bargemen work the handles of the windlass to raise the mast. The work is signed ‘W. L. Wyllie’, lower right.