I found a strange thing in goverment document named “Sailing Directions (Planning Guide and Enroute)”.
It says that mountains were sighted up to 300 miles away. Assuming observer is at “Crow Nest” at 115 ft ( 35m),Refracted hidden will be 8.83 miles. The highest mountains on Antarctica are 2.9 miles tall. Also, refraction is minimal at higher altitudes,like “Crow Nest”.
Here is document if anyone wants to check(search for 300 miles inside document ... Read even more