There are mine fields also, so definitely be careful if you plan on harbor raiding. Some of them fight back. The mine fields do "blossom" as time progresses. Not all "historical" areas protected by mines are covered in FotRSU. Subnets are used as "obstacles" in some shallows, to represent reefs and the like, but not all locations are done that way. It would be nice if the game could represent reefs better, but oh well...
