You don’t see this very often, but heavy winds and waves on Lake Michigan just destroyed a historic 20-foot navigational beacon near the entrance to Manitowoc Harbor, Wisconsin. “We don’t know where the tower went,” said Coast Guard Chief Eric Olson. “It most likely has been pushed into the lake.” The fiberglass beacon, known as the South Pier Light Navigational Beacon, was built on top of a concrete platform and has served as a nav aid for decades. But early one January morning the area was under a gale warning, with 12- to 15-foot waves and wind gusts up to…