I ran into this article about marine robots being used to map ship hulls for mines. It is a good read and another nice example of how robots can be used to inspect shipwrecks.
This article is also very interesting. It refers to a robot which managed to identify a black box under water and retrieve it. Of course this was a test performed in a pool, where there are a lot less limitations than in the sea. This is, however, very similar to what I want to pursue in my future. I plan to program robots to be autonomous when it comes to certain archaeological tasks. Of course, the difference between “find a black box in a pool, which has known characteristics and is in relatively clear water” and “find an object with unknown characteristics, that is old and probably covered in strange marine creatures in water slightly less clear than pool water” is quite large.