Related Clues:
- Hydroacoustic tool
- Sub navigation tool
- Relative meets artist coming back for listening device
- Fairies cope — such may help little folk to have a vision
- Torpedo detector
- Shipwreck locator
- Echolocation
- Hydroacoustic device
- Help in finding objects on a river bed
- Method for detecting submarines
- Sub viewer
- Navigating system
- Fish-finding device
- U-boat finder
- Submarine device