Volume Twelve - Pre-Victorian to the Present Day - further aspects - Report upon Penarth Dock - 1984 . . .

1963 - One final point was that in 1963 when alternatives were being proposed for dock development at Royal Portbury a scheme was suggested which involved a sea wall being built from Cardiff to a point near Penarth Head, a very similar idea to the 1853 scheme.

Appendix D - Half-tide Basins

The half-tide basin was a feature incorporated into many of the docks of the 19th century. Their use was brought about by the increasing number of merchant vessels and the consequent inability of conventional lock systems to handle them. The concept of the half-tide basin was attributed to a certain Jesse Hartley. [Dock Engineer to the Port of Liverpool, 1824-60]

In its simplest form the half-tide basin consists of a basin connected to a main dock via one pair of gates and to the sea via one further pair of gates. The half-tide basin was used as follows.

Vessels wishing to leave the dock would move into the half-tide basin just before the water level outside the basin was sufficient to allow them to navigate the entrance channel. Then the gates between the main dock and the basin would be closed and the basin sluiced down to the level of water outside.

Then the entrance gates would be opened and vessels would leave and enter the basin. This would continue until the level of water became too low to allow for the passage of vessels. When this occurred the entrance gates would be closed and the main dock sluiced down to the level of the water in the basin, the gates between the basin and the main dock opened and vessels allowed into the main dock to load or discharge cargo.

If the half-tide basin was suitably equipped then vessels could load or discharge all or part of their cargo in the basin without having to wait to enter the main dock.

In its simplest form the half-tide basin acted like a huge lock, however, if the single gates between the basin and the main dock were replaced with two pairs of gates to form a lock then a greater flexibility in the operation of the half-tide basin could be achieved. In this case vessels could enter the main dock immediately upon entering the basin if they required urgent dock facilities.