3 ms·
Sounds like they are using a [Buoyancy_engine](https://en.wikipedia.org/wiki/Buoyancy_engine https://en.wikipedia.org/wiki/Buoyancy_engine). The large wings are
by briandw 2y ago
Sounds like they are using a [Buoyancy_engine](https://en.wikipedia.org/wiki/Buoyancy_engine https://en.wikipedia.org/wiki/Buoyancy_engine).
The large wings are there to provide efficient forward motion when going up or down the water column.