This is the Vernon C. Bain Prison Barge.
It's moored but not permanently moored at the Rikers Island Complex. It is required by the Coast Guard to maintain a maritime crew, including a mate, an engineer, and an oiler. So here's the question, if an inmate or an employee is injured on the barge would it fall under admiralty jurisdiction? Believe it or not it appears the question has never been litigated, at least I can't find it in my search of federal and New York cases.