Kevin T of NB Tranquility got it. It is the breather for the ground paddles on a lock on the Huddersfield Narrow Canal. The pepperpot-shaped device seems to serve as a bollard or strapping post too.
This is at Lock 12W.
Stuff you might not (want to) know about ships - Ooh, before I forget, I must tell you what I forgot to mention last time. On our trip up the Ouse we got a hello from the resident seal that swims up an...
12 hours ago