Volume Three - The Pontoon Era - Notes on the longitudinal joint of the Penarth dock . . .

The method of coupling up the sections would depend somewhat on the form of joint packing used. If an ordinary round or square projecting packing is used, the joint should be first made at the top, and then allowed to close in on the bottom, compressing the packing. If liquid is to be inserted, the extension piece with the projecting lip below the joint angle should be ballasted to float a couple of inches or so below the main dock. Small bolts would be inserted to make sure that the vertical faces of the joints were together, when the extension would be gradually drifted up till it took its true position, when the lip would be pressing against the bottom of the other section without any danger of its being crushed against the other angle.

To place the Dock on an even keel, water will have to be run into the outer compartments until it floats at a draught from 3' – 6” to 4' – 0”, and the extension will have to be ballasted to produce the same draught. Something may be done by slightly tipping the Dock backwards, so that the draught at the joint is reduced, ballasting the extension to the same angle.

The extension must therefore be fitted with a longitudinal bulkhead about 4 ft. high, which must be watertight. It may also be noted that since the Dock has now tipped forward, it can again be tipped backwards by pumping, so putting a further strain on the bottom of the joint.

Note. It looks as if an elastic packing would be best, injection only being resorted to if the bolts fail to make the joint tight. Since the extension in the complete Dock becomes part of the outer compartment of the Pontoon, communication will have to be established through the bulkheads.