A lightvessel, or lightship, is a ship that acts as a lighthouse. They are used in waters that are too deep or otherwise unsuitable for lighthouse construction. Although some records exist of fire beacons being placed on ships in Roman times, the first modern lightvessel was off the Nore sandbank at the mouth of the River Thames in England, placed there by its inventor Robert Hamblin in 1734. The type has become largely obsolete; lighthouses replaced some stations as the construction techniques for lighthouses advanced, while large, automated buoys replaced others.
A screw-pile lighthouse is a lighthouse which stands on piles that are screwed into sandy or muddy sea or river bottoms. The first screw-pile lighthouse to begin construction was built by the blind Irish engineer Alexander Mitchell. Construction began in 1838 at the mouth of the Thames and was known as the Maplin Sands lighthouse, and first lit in 1841. However, though its construction began later, the Wyre Light in Fleetwood, Lancashire, was the first to be lit.
United States lightship Chesapeake (LS-116/WAL-538/WLV-538) is a museum ship owned by the National Park Service and on a 25-year loan to Baltimore City, and is operated by Historic Ships in Baltimore Museum in Baltimore, Maryland. A National Historic Landmark, she is one of a small number of preserved lightships. Since 1820, several lightships have served at the Chesapeake lightship station and have been called Chesapeake. Lightships were initially lettered in the early 1800s, but then numbered as they were often moved from one light station to another. The name painted on the side of lightships was the short name of the Light Station they were assigned to and was the day time visual aspect of the many Aids to Navigation on board lightships. The United States Coast Guard assigned new hull numbers to all lightships still in service in April 1950. After that date, Light Ship 116 was then known by the new Coast Guard Hull number: WAL-538. In January 1965 the Coast Guard further modified all lightship hull designations from WAL to WLV, so Chesapeake became WLV-538.
The Dames Point Light marked an 8-foot-deep (2.4 m) shoal at a sharp bend in the St. Johns River in Florida that was a danger to ships heading to or from Jacksonville.
A Texas Tower lighthouse is a structure which is similar to an off-shore oil platform. Seven of these structures were built in the 1960s off the shores of the United States. Automation started in the late 1970s, which led to the obsolescence of the housing built for the keepers which resulted in such a large structure. Three of the towers were dismantled over time due to deteriorating structural conditions among other problems, while another one was destroyed in a ship collision. The last Texas Tower was deactivated in 2016 having served for over half a century. Today only three of the former lights remain.
Southwest Ledge Light is an active lighthouse marking the main entrance channel to the harbor of New Haven, Connecticut. Completed in 1877, it was one of the first to be built on a cylindrical iron foundation, an innovation by Maj. George H. Elliot to address shifting ice that is regarded to be very important in lighthouse design. The lighthouse was listed on the National Register of Historic Places in 1990 as Southwest Ledge Lighthouse.
United States Lightship 101, now known as Portsmouth as a museum ship, was first stationed at Cape Charles, Virginia. Today she is at the Portsmouth Naval Shipyard Museum in Portsmouth, Virginia. Portsmouth never had a lightship station; however, when the vessel was dry docked there as a museum, she took on the pseudonym Portsmouth. A National Historic Landmark, she is one of a small number of surviving lightships.
The Craighill Channel Lower Range Rear Light is one of a pair of range lights that marks the first section of the shipping channel into Baltimore harbor. It is the tallest lighthouse in Maryland.
Wolf Trap Light is a caisson lighthouse in the Virginia portion of the Chesapeake Bay, about seven and a half miles northeast of New Point Comfort Light. It is listed on the National Register of Historic Places.
United States lightship Nantucket (LV-112) is a National Historic Landmark lightship that served at the Lightship Nantucket position. She was the last serving lightship and at time of its application as a landmark, one of only two capable of moving under their own power. She served as the lightship for such notable vessels as the liners United States, Queen Mary, and Normandie.
Frying Pan (LV-115) is a lightvessel moored at Pier 66a in the Chelsea neighborhood of Manhattan in New York City. It served at Frying Pan Shoals, off Cape Fear in North Carolina, for over 30 years.
The Ship John Shoal Light marks the north side of the ship channel in Delaware Bay on the east coast of the United States, near the Bombay Hook National Wildlife Refuge. Its cast iron superstructure was exhibited at the 1876 Centennial Exposition in Philadelphia, Pennsylvania.
The Elbow of Cross Ledge Light was a lighthouse on the north side of the ship channel in Delaware Bay in Cumberland County, New Jersey, on the east coast of the United States, west of Egg Island Point. It was destroyed by a ship collision in 1953 and replaced by a skeleton tower on the same foundation.
The Brandywine Shoal Light is a lighthouse on the north side of the ship channel in Delaware Bay on the east coast of the United States, west of Cape May, Cape May County, New Jersey, United States. It was the site of the first screw-pile lighthouse in the United States.
The Miah Maull Shoal Light is a lighthouse on the north side of the ship channel in Delaware Bay, off of Cumberland County, New Jersey on the East Coast of the United States, southwest of the mouth of the Maurice River.
Diamond Shoal Light is an inactive offshore lighthouse marking Diamond Shoals off Cape Hatteras.
The Detroit River Light, also known as Bar Point Shoal Light, was first established as a lightship in 1875. The current sparkplug lighthouse was built in 1885. It sits in Lake Erie, south of the mouth of the Detroit River, 1.75 nautical miles from land and about 20 nautical miles from the Ambassador Bridge in the Detroit River. It is about 0.4 nautical miles from the border with Canada, and just under 24 nautical miles from Put-in-Bay, Ohio. Its original 4th order Fresnel lens is on loan to the Michigan Maritime Museum.
The Musselbed Shoals Light was a lighthouse which once stood in Narragansett Bay at the west entrance to Mount Hope Bay, south of Bristol Point. As with many Rhode Island lights, it was a casualty of the New England Hurricane of 1938.
The Peshtigo Reef Light is a lighthouse in Marinette County, Wisconsin, United States, offshore in lower Green Bay. Constructed in 1936 to replace a lightship, it remains in service.
The Martin Reef Light Station is a lighthouse located in northern Lake Huron, 4.3 miles (6.9 km) south of Cadogan Point in Clark Township, Michigan. It was listed on the National Register of Historic Places in 2005.
