Seven Foot Knoll Lighthouse

Seven Foot Knoll Lighthouse. . , Seven Foot Knoll Lighthouse was the second screwpile lighthouse built by the U.S. Lighthouse Service. It was originally located 15 miles southeast of here in the Chesapeake Bay, marking the entrance to the Patapsco River and the approach to Baltimore Harbor. The 47-foot-high, round lighthouse was completed by the Baltimore iron foundry of Murray and Hazelhurst in 1856 at a cost of just over $30,000. It was constructed from rolled-iron plates, drilled and riveted together, and supported on nine cast-iron screwpiles which were screwed into the Bay bottom and eliminated a need for an underwater masonry foundation., The light at Seven Foot Knoll marked the outer entrance to Baltimore's busy harbor and was manned from 1856 until 1948, when the Coast Guard automated it. In 1988, Seven Foot Knoll Lighthouse was officially retired to Pier 5 in Baltimore's Inner Harbor. Today, this lighthouse is a National Historic landmark welcoming visitors daily., [Captions:] , This ca. 1900 image shows the Seven Foot Knoll Lighthouse in its original location at the entrance of the Patapsco River. Its screwpile supports were vulnerable to damage from ice and floating debris, and were protected with both stone and wood structures at various times throughout its history. The lighthouse was relatively isolated, but resupplied with boats that could be stored on davits seen in the image. In this picture, the lighthouse still has its bell, which was used as a sound signal to mariners during low-visibility weather., Left: This chart from the 1860s shows the original location of the Seven Foot Knoll Lighthouse at the entrance of the Patapsco River, 14 mi. from its present location. The small numbers represent depth soundings.