Reminds me of one of my first ships as an apprentice - my job was to go over the side on a bosuns chair ( same as in the photos) and to clean and then thistle bond rivet heads to stop them leaking oil from the tanks into the sea.
We passed through the Panama Canal and they said we would be charged a lot of money because we dropped oil into the water - we said it was not us but the Greek ship in front and we just made the oil come to the surface with our propellers - we would have got away with it but they made us anchor off the end of the canal and we found ourselves in an ever widening pool of oil - hohohoho