Concrete barges

Whilst walking the final stretch of the London Loop path near Coldharbour Point, I came across 16 concrete boats wallowing in the mud. Some had their bows pointing towards shore, as if trying to clamber onto dry land, whilst others lay marooned at random angles. Lengths of rusty reinforcing bar showed through gaps where the concrete had decayed.

When I got home, I decided to research them. These boats were built in the early 1940s to cope with the increased wartime need for vessels. They are technically called ferro-cement barges - the advantage of concrete being that less steel was required in their construction, at a time when steel was scarce. The barges were also not expected to last long, whereas a ship might be designed to serve for decades. Each weighs about 200 tons, and were constructed at the London Docks before being craned into the water. These particular ones were built for handling and transporting petrol.

It is rumoured that barges of this sort were used in the D-Day landings and Mulberry Harbours, perhaps as parts of the floating roadway. Whether these particular vessels were used or not, they were dumped on the riverside after the 1953 floods to act as coastal protection, and have lain there ever since.

Or have they? They seem in a slightly odd arrangement and location for that to be the case, at least to my inexpert eyes. Were they used, and then moved to be dumped at their current location once the defences had been repaired?

They appear to be in surprisingly good condition given they were built around 75 years ago, and have been abandoned for over 65. Whereas wooden vessels soon disintegrate except where they are buried in sand, and metal rusts to nothing, some of these concrete boats appear as though they could be refloated and used - although that is almost certainly a false appearance.

The concretebarge.co.uk website has details on how similar vessels were made (although I believe not these particular ones) - including an interview with the designer! It's interesting to see Gunite was used - an early version of the shotcrete used in civil engineering nowadays.

At times the Second World War can seem rather distant. It is therefore good to see some concrete reminders of the war - even if it is in a rather bleak, industrial and wind-blown spot on the Thames Estuary.