this is NCD, so anything is possible, but in a more serious way of thinking, Turkey is still a member of NATO so even if US fleet can’t enter the black sea, they can stay in national turkish water as long as Erdogan does not explicitly eject them and having a US fleet inside the Bosphore is a good way for US to show muscle and put pressure on any nation bordering the black sea without even entering the black sea.
this is NCD, so anything is possible, but in a more serious way of thinking, Turkey is still a member of NATO so even if US fleet can’t enter the black sea, they can stay in national turkish water as long as Erdogan does not explicitly eject them and having a US fleet inside the Bosphore is a good way for US to show muscle and put pressure on any nation bordering the black sea without even entering the black sea.