I talked with captain of submarine. He said, in real life navigation was not reliable, so they have to go to surface and make adjustments with some classic navi

I talked with captain of submarine. He said, in real life navigation was not reliable, so they have to go to surface and make adjustments with some classic navigation - radio beacons and star navigation. And civilian education now close to forgot star navigation, but navy still train people to navigate with stars and learn Morse code. https://news.ycombinator.com/item?id=43319923 https://news.ycombinator.com/item?id=43319923