“USNS” ships are not manned by US Navy crews.
Not sure but do they fall under the MSC (Military Sealift Command)
My late father had the practice as a merchant marine officer of going to the bridge about fifteen minutes before his watch started in order to get acquainted with the position, course, and condition of the ship, the sea and weather conditions, and any ship traffic.
Here is how that can matter. One night, years ago, on a coastwise run in the Gulf of Mexico, the mate on watch wanted to bug out as soon as my father arrived. He insisted that the mate stay to the end of his watch and started asking questions about the ship's position and where they were in relation to ship traffic.
My father realized that the answers he got did not jibe with the lights that he was seeing in their direction of travel. Instead of being shrimp boats, they were ships in their correct lanes, which meant that their ship was badly off course and at risk of a collision. The mate started arguing, so my father ordered the helmsman to make a change of course and called the captain to the bridge to explain what had happened.
The next day, the ship put into Mobile on schedule. The captain had a quick telephone call with the shipping line's office. Within a few minutes, the derelict mate was gone and a replacement was on the way. Screw up in the Navy or as a federal civil service mariner and you may get an investigation and a hearing. Screw up on a commercial maritime vessel and you get sent home.
A couple of years ago, problems with GPS interference led to the US Navy to reinstitute a long discontinued course at the Naval Academy in traditional celestial navigation. To do so, the Navy went to the Merchant Marine Academy for help. They had kept such training and a large supply of sextants even after the Navy had dropped it.