Volume Five - The Age of Decline & Crass Stupidity - How do you lose a pontoon 115 metres long? . . .

The other factor to consider is that the south-side of the dock and the centre area is most probably slightly deeper than close by the berthing locations at the quaysides.

It is, therefore, reasonable to assume that as the pontoon neared journeys end at the bottom of the dock, the water trapped between the mud and the flat underside of the pontoon would soften the impact and possibly “aquaplane” the pontoon further outwards and into the deeper water. One could image that it could also rotate, even perhaps, 180 degrees about!

I recall that the last 20’–0” (6.1m) or so, of steel hull, mostly consisting of a steel deck extension with lots of angle iron supports below, sticking out from the dam was at a slight angle to the quayside, although I did not get my theodolite out of my pocket and survey it! From memory, my best estimate of where the “pointed bit” lies is approx. 100–150 feet (30–45m) away from the quayside.

Was this witness steelwork the bow or stern? We shall never know unless Time Team gets digging someday soon!

One lunch-time in the summer of 1966, Bill Muir, a fellow apprentice and I were daft enough to swim the dock. The water was horrid and there were millions of jellyfish; startled mullet darted about close-by. The water was definitely not clear, it was brackish and I suppose you couldn’t see much deeper than a couple of feet below you.

I couldn’t comment upon the clarity of the water on the appointed day of the pontoons’ last dive but, I could imagine that after the first metre or so, only ripples and bubbles would be witness to her true bearing and attitude during her final decent.