DESCENT S1 BUOY

The Garmin Descent S1 Buoy puts the surface crew inside the dive team's data. It floats above the dive and relays diver position, depth and tank pressure topside over SubWave sonar, the one link in the system that works underwater.

The buoy is rated IPX8 to 10 metres and weighs 981 grams. SubWave reaches up to 100 metres line of sight underwater, and the Wi-Fi link to a surface device reaches 60 metres. An internal rechargeable lithium-ion cell runs up to 15 hours and charges over a clip cable with a USB-C connector. GPS and GLONASS fix the buoy's own position, and Bluetooth and ANT sit alongside for pairing.

The result is a boat crew watching eight divers rather than a bubble line. Tank pressure, depth and location arrive topside wherever divers carry a compatible Descent computer and a T2 transceiver, with automatic alerts when a cylinder runs low. Divers below read distance and direction back to the buoy on the wrist, which amounts to a shot line that drifts with them.

Full function needs a Descent T2 transceiver on each cylinder and a compatible Descent dive computer, both sold separately. Without them the S1 works as a GPS surface marker rather than a monitoring station. It suits charter operators, instructors running students and any team diving in current.