Volume Three - The Pontoon Era - The new pontoon commissioning and its early use . . .

Pumping Trials: The Dock is required to lift a vessel of 4,200 tons displacement and of maximum draught of 18 feet within the space of time of 75 minutes, counting from the time the ship is centred on the blocks and pumping is commenced until the Pontoon deck is lifted out of the water, due allowance being given for any stoppage of machinery for the purpose of berthing the vessel. It was shown in the pumping calculations that to lift such a 4,200 ton ship of 18'- 0” draft, the amounts of water to be pumped and the work to be done are as follows:-