Volume Three - The Pontoon Era - The plant specification, pumping plan and operation of the pontoon . . .

So how did the master keep the pontoon level? In the earlier floating docks the pendulum was considered the answer. Then two spirt levels placed at right angles to each other was the norm. I'm not sure what was provided for the Penarth pontoon.

The ship was positioned longitudinally using the steam powered capstans attached at each end of the wall. The lateral position was adjusted manually by the side shores and great skill and experince was required to get the ship aligned exactly on the centreline of the pontoon so that the keel of the ship was centralised in each axis and upright. Then, and only, then would the keel sit on the keel blocks in the correct position on the deck of the pontoon. The keel shores were adjusted once the ship was out of the water to provide increased security.