"Unships" is a relatively uncommon word, and so there are few direct synonyms. However, some alternatives which convey a similar meaning might include "disembarks," "unloads," "docks," or "offloads." These words suggest a vessel or ship arriving at port, and its passengers or cargo being removed. In a broader sense, "unships" might also be thought of as meaning "detaches" or "disconnects," as if something were being separated or removed from a larger structure or system. As with many specialized terms, the exact nuances of "unships" will depend on the specific context in which it is being used.