Re:Old news (Score 2, Insightful)

light houses not only let you know where the coast line is, but often where submerged rocks are, which would not show up on radar. An example is the Duxbury Pier light in Plymouth Harbor (MA). While the rocks the light warns boaters from are clearly visible during low tides, at high tides they are completely submerged. The light marks the entrance into three different channels in Cape Cod Bay, and without this light there would be daily accidents.