Thanks Eliot! Long time viewer, first time poster!
Our AUV communicated wirelessly underwater only while it was docked. A Raspberry Pi 4 acted as our onboard flight computer, and we set it up to emit a WiFi hotspot using RaspAP. Our “surface station” was a simple laptop, and we connected it to an external waterproofed WiFi antenna attached to the dock. When the AUV was docked, the laptop could see the external hotspot from the vehicle and make a connection.
This WiFi communication was only possible at very close distances underwater, about 5-10cm, but it worked completely fine with no hiccups! Really great way to send a ‘launch’ command to our vehicle or monitor it while it was idle and docked. 