This seems to be a widespread issue on PvP Global. Every 20 minutes, regular as clockwork, ship halts wherever it is for 2 minutes, goes underwater and the recovers. If this continues I want a Redeemable Fulton's Nautilus! Has happened about 5 times this afternoon (BST)
Reported on F11 which gave position as 0,0 although I was in Charleston port about to dock.