| Clue | Source | Date |
|---|---|---|
| The Navy's New London site, e.g. | Wall Street Journal | 19 Aug 2023 |
| Where some underwater craft are sheltered, briefly | Universal | 01 Mar 2022 |
| The Navy has one in Groton, Connecticut | Wall Street Journal | 26 Sep 2020 |
| Naval fortification | LA Times Daily | 03 Feb 2018 |
| Naval fortification | The Washington Post | 03 Feb 2018 |
| Naval fortification | ||
| U-boat home |