Geograph - photograph every grid square

Inside Braunston Lock Number 2

The boat has just entered the lock through the open tail-gates (behind the viewer to the west). Currently the water level matches that of the pound to the west. There is room for two narrowboats in this broad lock. In front is a level cill onto which the head-gates shut and seal. Coming down the lock the stern of the boat must be kept clear of that cill otherwise the craft will be tipped bow downwards as the water level drops. However in this picture the boat is ascending, so when it is safely into the lock the tail gates can be closed and water let into the chamber. When the lock is full the head-gates are opened and the boat sails out into the next pound to the east.