It's only 10 meters long, it'd have a tough time going out of coastal waters no matter what. (Unless it's very resistant to being flipped or swamped, which I suppose is possible.)
The project commenced in 2014, according to Guo Tianyu, one of the company’s key account managers
A first prototype of the SeaFly completed phase one tests on Nanhu Lake in Wuhan on 27 October. The system, dubbed SeaFly-01, measures 10.25m long and can achieve a speed of 45km/h via two diesel engines.
The SeaFly will displace 4.5t and has an endurance of 400+km. The carbon fibre hull employs a ‘double-M’ configuration for speed and stability, and it can operate in up to Sea State 4 in all types of weather.
A monitoring centre can transmit commands to the USV at distances of up to 50km. However, the USV is capable of totally autonomous operations, plus it is able to learn autonomously.
Its core equipment was all developed within China and it operates using the Beidou navigation system
stealthy low radar cross-section
[0] https://www.shephardmedia.com/news/uv-online/zhuhai-2016-sea...
[1] http://www.sifang-electric.com/index.php/en/ and http://www.sf-auto.com/Pages/default.aspx
A wine cork can cross the ocean. If you filled all voids in an unmanned boat with expanded polystyrene, it would be assuredly unsinkable, unless you physically tore the hull to pieces.
why bother being above the water if there are no crew on board to breathe air, anyway?
it seems like a submersible would be ideal for certain military applications, patrolling, or whatever else you'd use a robot boat for.
also, I'd bet drug smugglers would really appreciate getting their hands on an unmanned submersible.
A submarine would have to be very autonomous, though. Getting a high-bandwidth signal to it for real-time control (without it surfacing) would be a huge challenge. A surface ship can just use old-fashioned radio.