As a sailor, it was infuriating when I would come across a container ship or some grain hauler with their AIS turned off.

Luckily I have other safety systems in place but damn is that a buzz kill at 3am on a new moon night.

Also another reason you would turn off AIS is if you are hauling precious cargo and don’t want pirates to know your whereabouts. I know this sounds cliche but it’s true. Cargo vessels traveling near pirate activity will often “go dark” to avoid detection and dealing with a Capt. Phillips situation.

So yeah, it’s difficult to get a fix on just how many vessels are out there, big or small. I’ve seen a lot of weird designs and contraptions out at sea.