| Answer | Crossword Clue |
|---|---|
| SEALAB | Underwater research site |
| DIVINGBELL | Underwater research vessel |
| SEALAB | Underwater test site |
| SEALAB | Underwater experiment site |
| pingers | a device for producing pulses of sound (as for marking an underwater site or detecting an underwater object) |
| pinger | a device for producing pulses of sound (as for marking an underwater site or detecting an underwater object) |
