Surveillance Center K-21B is a seemingly abandoned shack housing the entrance to a military research outpost deep within the Glowing Sea. Inside the bunker, several US Army Remnants, including one in power armor guard a research station occupied by many Enclave scientist.
At the bottom floor, a Terminal can be found with the Federal Surveillance Center K-21B Terminal Entries, which indicates that the Coast Guard Pier holds the location of the FMS Columbia.