ReconRobotics is making a seafaring version of its ReconScout Throwbot, a one-pound remote-controlled robot that can be tossed into a building and zip around taking video surveillance, sending the feed back to its controller. This new bot has magnetic wheels that let it drive straight up a vertical metal wall--meaning that if anti-piracy forces toss the robot onto a ship's hull, it can climb on board and send back valuable video recon.
Magnetic Swarming Snitches
Throwable Robot Can Climb Aboard Ships, Spy on Pirates
Score another one for Philip K. Dick... he predicted small robotic snitches in "The Man Who Japed" in 1956.
It's a little noisy. I suppose it would work great on a ship, not so much anyplace quiet.