Sleepers stored near a bridge
These are used to block of canals when work is needed - they slot into the sides of the canals where they narrow at bridges, one on top of the other until the flow is stopped - then the area between 2 lots of stacked sleepers can be pumped out. On the K & A they use steel girders and have 2 chaps in sub-aqua gear to put them in place. They also fly the International Code flag 'A' which means 'I have a diver down' - all in 3' of water, ha ha.