Garmin scuba diving products now have underwater communication features built in. Unfortunately they're locked down so you can't use them for any other purposes.
For those who aren’t scuba divers, 10m range is very impressive. Most radiowave-based systems have a range of 1-2m, with many being plagued with connectivity issues.
One of the main use-cases is air integration, which allows you to have a transmitter connected to your cylinder which monitors gas pressure and relays it to the dive computer on your wrist.
This is an alternative (or, depending on the school of thought, in addition) to having an SPG (submersible pressure gauge) which is hopefully attached to your left d-ring, but for many recreational divers stuffed in a pocket somewhere or scraping on the bottom.
Air Integration is quite an investment (3-500€ per transmitter) and there is basically no interoperability between brands.
When Garmin came out with this, it made quite a splash, as all of a sudden instructors could keep an eye on the cylinder pressure of their students. This is a very minor use-case though, and I don’t believe it’s used a lot.
As for underwater communication, a good chunk of the scuba community is quite opposed to relying on electronics for communication. Hand-based signals are quite good, underwater paper does exist, and if you’re so far from your buddy that you need to wirelessly communicate you’re in a lot of trouble.
This all being said, as a boat captain responsible for the people underwater, I would love a local area network that allows me to pull the plug on a dive, or get some emergency notification. For example “weather is turning, please call the dive” or “I was blown off the wreck, please pick me up”.
> This all being said, as a boat captain responsible for the people underwater, I would love a local area network that allows me to pull the plug on a dive, or get some emergency notification. For example “weather is turning, please call the dive” or “I was blown off the wreck, please pick me up”.
In case you are interested, there is a Finnish company called UWIS (short for underwater information systems), that does exactly this [1]. Their system has buoyes that can track the diver units and provide communication channel between on the surface pc and the divers via wifi and sonar network. The system allows two way communication. Tight bandwidth of course as a limiting factor.
Garmin occasionally sends me customer surveys, and the questions on a recent survey implied that they were looking into boat to diver communications as a use case. I don't know whether they're actively working on this, but it seems like it could possible to add to future versions of their boat sonar products.
https://www.garmin.com/en-US/garmin-technology/dive-science/...