This shit is extremely weird and happens all over. For some reason sailors are just absolutely not allowed off their shitty falling apart ships and have to stay on board even after the owners vanish and leave them hanging in the wind. There are sailors trapped in this situation in ports all over the world - the ships are too damaged to sail, or the owners vanished without paying port fees and the ship is impounded, or whatever. Weird shit. And all these sailors, mostly from global south countries, are trapped. The country they're stuck in won't let them off the ship, they have no way to pay for port fees or fuel and sometimes even food or water. It's utterly fucking bizarre.
I don't think it's a large number of ships in absolute terms, but it is common in the sense that at least a few ships are trapped in this limbo all the time. There's this whole world of ultra-shady shipping with ships that are registered in sketchy tax haven countries, or have no registration, and they get abandoned all the time. And sailors in general just get treated like shit. A lot of sailors come from poor global south countries and get treated as disposable. Terrible conditions, bad or no support from the ship owners, if something goes wrong they can be stranded and totally fucked. It's a mess, like a serious problem for workers.