Go on. Whats the thing with the first dock gates photo?
Dock gates only work compressed by the water pressure.
What are the other gates?
I know as first boat I ever worked on was without a bow at more than 4" above the water line as he had run the boat into Bromborough Dock gates.
The bow was 3/4" or 1" steel gates tend to be tough.
Whats the thing floating in the second photo?