"Relatively simple" is probably relative.
As others note keeping the electronics alive is going to be hard enough, but the "ping back" is probably the hardest bit.
There is no such thing as mobile connectivity in the middle of the ocean, because there are no cell towers, so your only bet is to use satellite hookups.
Satellite connectivity for things like this is pretty good today, with providers like Iridium providing low bandwidth ping services like their Iridium Short Burst Data Service.
You would use something like the Iridium 9603[0] which idles at 34mA and uses 0.8W to send a message.
That is to say it's all definitely doable, but probably not that simple and much much easier to do today then even 10 years ago.