You have to be in visual range, or radar range if you have one, which is the horizon plus a bit more depending how high above sea level your are and how tall your target is.

If you're on a ship, unless you're using an advanced radar that bounces signals against the ionosphere or you have a meteorological phenomena called an inversion which can curve your radar energy over the horizon a little bit, your radar horizon is surprisingly short, something around 12 nautical miles give or take. And the sea is big and Iran is quite far.

This is one big reason why aircraft are used for surveillance at sea. They can go much higher than any ship's radar antenna mast every could be which significantly expands their radar horizon. They can also scan a huge area relatively quickly as they can travel much faster.

Because if this fuck up, Iran now has the intel that the French carrier is approaching without even having to send an aircraft out to look for it. If they even still have the ability to do so at this point.

I saw the location on one of those "war dashboards" a day or two ago. Can't have been that secret.

And here we are, fifteen years later.

Yep. This has only been an issue for nearly a decade.

The Strava Heat Map and the End of Secrets

The revelations began unspooling at a rapid pace after Nathan Ruser, a student studying international security at the Australian National University, began posting his findings via Twitter on Saturday afternoon. In a series of images, Ruser pointed out Strava user activities potentially related to US military forward operating bases in Afghanistan, Turkish military patrols in Syria, and a possible guard patrol in the Russian operating area of Syria.

Other researchers soon followed up with a dizzying array of international examples, based on cross-referencing Strava user activity with Google Maps and prior news reporting: a French military base in Niger, an Italian military base in Djibouti, and even CIA “black” sites. Several experts observed that the Strava heatmap seemed best at revealing the presence of mostly Western military and civilian operations in developing countries.

I remember reading that. My brother is in the AF, and through some system, they can get gear like Garmin Fenix watches that does GPS tracking and uploads to their cloud and can be synced with Strava. It's wild that stuff like this isn't strictly monitored to prevent this exact scenario.

Its kinda the best way to make politicians care about privacy. Make them feel watched by the big brother they're trying to implement

Imagine losing a carrier because a major world power's military IT security is so incompetent they're allowing sailors on active deployment to have unfettered internet access.

that's how it looks when you walk/run in circles in a vessel that's moving

He's running up and down the deck