Question: How many arcs were there in totality? Because I saw IV and III being noticed, but not the rest.
Answer: At one point towards the end of the movie it is revealed that only 4 of the ships are operational by the time the apocalypse starts. When we get to the port, it's revealed that the ceiling collapsed on Ark 3 during the earthquakes. This leaves 4, 6 and 7.
There were a total of nine arks. However, arks 1, 2, 5, 8, and 9 were never completed or even built. As for ark 3, a major earthquake occurred at some point and caused the roof to cave in.
Answer: That question, it seems, cannot be answered 100%.For example, rather at the beginning of the movie, you can see the Chinese army blasting five huge caverns into the mountain that will become the port soon after.On the other hand, at the end of the movie, there appear to be an Ark 6 and 7, being reported to join with Ark 4.