Mystery ships - Barracks ships?

[Geoffrey Green]

In the mystery ships area I have posted a number of photos of ships on military service on the Saigon River in 1972. Two of these photos show what appears to be barrack ships. Can someone provide their purpose? Were they self propelled or towed? They must have had some pretty powerful a/c - there doesn't seem to be any vents or opeings for natural sunlight. What happened to them? Were they actually command ships?