I had a flash into the future when I saw the video of goundbot rolling thru the ocean.

Unlike stationary bouy's These bots can travel giving it the ability to move in for a closer look.

Autonomous Waterbots by the thousands patrolling the waterways. Mostly just siting around waiting for something to pass within a few miles of it then alerting a central station that reports back whether it is friend or foe or perhaps a stranded vessel.

The outter shell of the ball itself would be flexiable durable solar cells to power the unit.

Equipt with GPS and Radar they could autonomously navigate towards or away from shipping as to avoid collisions. Perhaps they can detect and track tsunamis.