What are sonobouys?

Sonobuoys are sound sensors specifically designed for use in underwater acoustic surveillance and communication. Their primary function is to detect and track submarines or other underwater activity by listening to sounds in the water. When deployed, these devices send and receive transmissions that can provide critical information about the underwater environment, including the location and movement of submarines.

Each sonobuoy has a microphone that picks up sounds from the water, and the information is transmitted back to a receiving platform, such as an aircraft or a surface ship. This capability allows for real-time monitoring of underwater activity, which is essential for anti-submarine warfare and maritime security operations.

In the context of other options, while various devices and buoys serve different purposes in maritime operations, only sound sensors like sonobuoys specifically focus on sending and receiving underwater acoustic transmissions.