The Tidal Gates. Designed to allow the tide rise and the sea to enter the pool.
They were closed, and the sluices closed, until the right time, and the sluices opened.
Looking at the gate edges, it appears that they were edged with bands of oiled leather.
The sea-water-facing side of the gates; the pressure on these gates at full pool and low tide must have been immense.
9th May 2009.