Rivet City bow

About
Although technically a part of Rivet City, the Rivet City bow consists of the broken of third of the aircraft carrier. Pinkerton has setup his lab within the bow part of the carrier after being 'removed' from the Rivet City council in a coup.

Access to the bow is made via an underwater door. Some distance must be swum, and there is a hollow section half way along in which a breath can be taken. The entrance is guarded by Mirelurk Kings so come out guns blazing. (That is not entirely true. Your level will determine what kind of Mirelurk you will encounter. At level 4 you will encounter 2 Mirelurks). The higher your level the tougher the enemies.

Another entry is south west of Rivet City across a bridge. The door is locked "Very Hard" (requiring a Lockpick skill 100), but can be unlocked from inside, allowing easy reentry.