There is an interesting dry dock below Denham Deep Lock. It’s the first floating dry dock I’ve seen on the canals.
A large wide beam barge has been modified by removing the steel stern and replacing it with a timber plank dam.
It appears the original stern was removed apart from the last 2ft. The barge must be pumped full of water until it’s either on the bottom or sufficiently deep in the water for a boat to enter. The planks are then fitted and the water inside pumped out
It appears there is downward pressure on the planks using a clamp system. I assume this is done to keep them water tight during the re-floating.
It’s probably a very low cost way of making a dry dock. It can even be relocated.
Denham lock lower gates had a strange pattern on them. It might look like water flowing over the top however it’s foam. I’m not sure why this would be the only lock with a layer of foam on the surface?