This is what I've figured out:
Top line:
Surface detectability range (( )) Air detectability range
>> Maximum speed
...third symbol I'm not sure of; it looks like a gun, so I'm thinking the AA rating
Second line:
Max range of torpedoes ||| Reload time in seconds
Max range of guns (before captain skills or mounted upgrades) (+) Reload time in seconds
For CVs, it lists the max torpedo damage