Seacove never requests your phone’s location. There is no “share my location” permission to grant, because the app doesn’t use one.
Instead, the Ports tab and port overlaps use your ship’s public sailing schedule, the same kind of information available to travel agents and passengers. This tells us roughly where your ship is going and when, without ever touching your phone’s GPS.
If your ship’s schedule hasn’t been reported yet, the Ports tab says so plainly, rather than guessing.