It's part of a warehouse or shipyard. The buildings are gone and if they look around they might find some sign of them, but possibly not if they were just sitting on the ground. Docks, too.
Seems to me that if a shipyard was getting relocated or abandoned, the stuff would have been moved along with the ships.
I prefer to think it was a plot of some sort that got disrupted. The shipyard was already abandoned and some yahoos were using it to store up materials for nefarious deeds. They got caught but never spilled the beans about where they’d laid up all their ill gotten gear.