A big container ship like "Vermaas" would not have stern a thruster in reality, so she is correct in the way she is shown on Ship Simulator. The "Ocean Star" has two azipod drives at the stern which if rotated to 90 degrees or 270 degrees act as if they were a stern thruster, so she does not need an ordinary thruster at the stern. The VLCC "Latitude" would never be in a position to need one so she too is correctly modelled. Any manoeuvering she needed would be with the aid of tugs. Does that clear up the matter for you? "Fairmount Sherpa" is specially built to enable her to be held on station in a fixed position whilst serving oilrigs in heavy weather so she needs to be very manoeuverable that is why she is fitted out the way she is.
Angus.