Pontoon bridges are just linear open-sided waterbeds.
Transcript Under the Cut
In 3807 BC, the Neolithic Britons of the Brue Valley came together to construct an elevated, single-plank walkway over a reed swamp. Stretching nearly two kilometres, it would have provided a vital link for communities on the Somerset Levels, and is the second-oldest timber trackway discovered in the British Isles.
The track was a walkway consisting mainly of planks of oak laid end-to-end, supported by crossed pegs of ash, oak, and lime, driven into the underlying peat; the length, straightness, and lack of forks or branches in the pegs suggest that they were taken from coppiced woodland—one that they appear to have been managing for at least 120 years.
The total timber used in the track’s construction weighed approximately 200,000 kilograms, yet estimates suggest just ten men could have assembled it in just one day. The track was operational for only about ten years before rising water levels likely submerged and rendered it unusable.
On the off-chance that people don’t know this...
This style of bridge dates from the days when barges were towed by horses. When the towpath switched to the opposite side of the canal, the horse would, obviously, clippy-clop over a bridge and happily plod off again. Now, the automatic way to do this would be like this:
However, note that rope (black line) between the horse (brown blob) and the barge (red blob). If you cross the bridge the automatic way, it all goes a bit....
However, if you cross the bridge like THIS
it all works out fine!
Now, sure, you could trust people to remember how to cross a bridge. But there are a lot of numpties out there, and people were working extremely long days and were extremely tired. Also, the canals were BUSY. One boat getting snarled up was the equivalent of the Ever Given.
So, instead, the canal companies built Numpty-Proof Bridges.
They also had the benefit that the horse could be left to plod along on its own, rather than needing human guidance. (I have no idea how this worked. My horse would have her nose buried in the grass and wouldn’t go anywhere, if I left her to it.)
WHAT
*mind blown*
I thought this about a lot when I was a kid
I was wondering about that one too…