iPhone 16 satellite feature disappears when beyond 10 miles offshore

I recently upgraded to iPhone Pro 16 specifically for the satellite capability that would allow me to text my location coordinates in an emergency when boating ~40 miles offshore near Naples, Florida in the gulf. I’ve tested it twice and each time it works till I get beyond about 10 miles out, then the satellite feature is gone, no longer where it was 30 minutes earlier. There’s no cellular or WiFi out there. I tried turning them off as well but still no satellite feature.

To repeat, the satellite feature was there (control panel) and worked, then disappeared with no where to be found once we boated beyond about 10 miles out. This was the whole reason I bought the phone.

Is there anything that can fix this, upgrade, replacement, etc?