Ships like you describe are also often weirder with what they transmit. Cargo and cruise ships go from known port to known port in reasonably predictable ways. (Reasonably predictable meaning that 50 or so regexes can usually extract a little sense from what some sailor types into a bridge console.) But a lot of data from smaller, less predictable ships is much less regular.
Now that it has been running a while, I should definitely go back and see what else I can extract from the data. But one of my problems is that this stuff is poorly documented. What I really need is connections to maritime experts who can look at the data and say, "Oh, that ship is..."
