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28-473: It extends roughly 230 km (120 nmi; 140 mi) from Fowey Rocks , off Key Biscayne, to Sand Key , off Key West. Its width ranges from approximately 10 km (5.4 nmi; 6.2 mi) to 0.40 km ( 1 ⁄ 4  mi) wide at its narrowest part. It varies in depth from 7 to 8 m (23 to 26 ft) off the Upper Keys along the center of the channel to 12 to 15 m (39 to 49 ft) off

56-502: A hurricane wrecked 19 ships of the Spanish treasure fleet on Florida Reef along Hawk Channel. The remaining survivors camped on the nearby Indian Key until they were rescued. With the construction of Henry Flagler 's Overseas Railroad in 1905, four predominant channel passages were dredged perpendicular to the Keys and the railroad's various bridge extensions, including Moser Channel through

84-505: A 0.06 degree angle into Hawk Channel. A sand ridge lying between Hawk Channel known as "White Bank" is the closest of the two ridges off of the Reef Tract and is subject to open tidal exchanges with the Atlantic. The passage is considered a dividing-line between inshore non-reef and offshore reef areas. The warm, nutrient-deficient waters that circulate through this exchange are conducive to

112-525: A distance. Beginning as early as the 16th century, numerous merchant ships wrecked off of the shallow reefs of Hawk Channel while sailing along notable shipping lanes within the Gulf Stream, expanding the prosperous wrecking industry off of the Southern coast of the Keys. Increasing revenues brought the islands' first settlements in 1822, bringing the fishing industry 's use of the passage with it. In 1733,

140-642: A modern solar-powered light. Although owned by the National Park Service, the light continues to be maintained by the US Coast Guard. Cave dive sites: Sverdrup In oceanography , the sverdrup (symbol: Sv ) is a non- SI metric unit of volumetric flow rate , with 1 Sv equal to 1 million cubic metres per second (264,172,052 US gal/s). It is equivalent to the SI derived unit cubic hectometer per second (symbol: hm /s or hm ⋅s ): 1 Sv

168-588: Is equal to 1 hm /s. It is used almost exclusively in oceanography to measure the volumetric rate of transport of ocean currents . It is named after Harald Sverdrup . One sverdrup is about five times what is carried by the world's largest river, the Amazon. In the context of ocean currents , a volume of one million cubic meters may be imagined as a "slice" of ocean with dimensions 1  km × 1 km × 1 m (width × length × thickness). At this scale, these units can be more easily compared in terms of width of

196-541: Is named in honor of the Norwegian oceanographer, meteorologist and polar explorer Harald Ulrik Sverdrup (1888–1957), who wrote the 1942 volume The Oceans, Their Physics, Chemistry, and General Biology together with Martin W. Johnson and Richard H. Fleming. In the 1950s and early 1960s both Soviet and North American scientists contemplated the damming of the Bering Strait , thus enabling temperate Atlantic water to heat up

224-573: The Florida Current pushing water northward from the Atlantic with a velocity of 1.8 m/s (3.5 kn) and a mean transport of 30 Sv . Hawk Channel's ocean floor also makes up the eastern escarpment of the Florida Platform where the Florida Peninsula lies 3 to 4 mi (4.8 to 6.4 km) from the platform's edge. Sand Key Light, the marker indicating the southernmost portion of

252-638: The Florida Keys and serves as the continental shelf for the Florida Keys Atlantic side . It lies south or southeast between the mainland keys and an extensive reef tract 8 km (4.3 nmi; 5.0 mi) offshore. The Florida Reef Tract, a band of coral reefs along the southeast side of the Florida Keys, is located on a narrow shelf that drops off at the Florida Straits and slopes seaward at

280-493: The Gulf Stream . Roughly 53 mi (85 km) south of Fowey Rocks, the channel cuts through John Pennekamp State Park , the adjacent federal sanctuary , and Hens and Chickens reef passed the 33 mi (53 km) length of Key Largo before continuing next 30 mi (26 nmi; 48 km) to Key West. Hawk Channel provides comparatively smooth waters protected from Gulf Stream powered winds except when passing through

308-786: The Seven Mile Bridge . These channels allowed the passage of boats and tidal exchanges from the Florida Bay and the Intercostal Waterway into Hawk Channel. Additional channels include Long Key Channel, Channel 5, and Channel 2. In November 1822, the USS ; Alligator ran aground on a shallow reef off of Hawk Channel while escorting a convoy of merchant vessels. The United States later sank her in order to prevent its remains from being salvaged by pirates . The wreck lies 4 nautical miles (7.4 km; 4.6 mi) east of Indian Key, near

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336-509: The Florida Keys and its surrounding waters, including Hawk Channel, were inhabited by the Calusa and Tequesta tribes. On 15 May 1513 , the Spanish explorer, Juan Ponce de León , and his fleet sailed south from Biscayne Bay along Hawk Channel through the Florida Keys. While charting the surrounding waters, he named the islands Los Martires ("The Martyrs"), as they reminded him of suffering men from

364-680: The Keys, produce a current of up to 3 to 4 knots (5.6 to 7.4 km/h; 3.5 to 4.6 mph). Vessels will often use beacons on the Florida Reef as guides in order to navigate through the entrance of Hawk Channel beginning 10 mi (8.7 nmi; 16 km) south of Miami 's Government Cut and 3 mi (2.6 nmi; 4.8 km) south of the southern tip of Key Biscayne, with the crossover between and Biscayne Bay averaging about 4.5 ft (1.4 m) in mean low water (mlw). Most non-commercial vessels may avoid Hawk Channel due to effects of local currents and considerable commercial traffic in

392-709: The Matecumbe Keys, north of Alligator Reef itself, and is marked by the Alligator Reef Lighthouse . In June 1748, the Royal Navy frigate HMS  Fowey struck a reef off of Hawk Channel. She sank on 26 June. A few miles south of Cape Florida , the Fowey Rocks Lighthouse, named after the frigate, was constructed in 1878. While construction was still underway, the SS ; Arratoon Apcar ran aground on

420-619: The Middle and Lower Keys. A course in Hawk Channel roughly 3.2 km (2 mi) offshore is partially protected by the deepwater of the Straits of Florida and allows vessels drawing roughly 2.1 to 3.0 m (7 to 10 ft) to avoid the adverse currents of the Gulf Stream while crossing through the Keys. 24°47′N 80°47′W  /  24.783°N 80.783°W  / 24.783; -80.783 Hawk Channel has an orientation parallel to

448-464: The boat failed, and she was pounded apart on the rocks and sank. Today the wreck is an excellent scuba diving site. One early assistant keeper of the lighthouse, Jefferson B. Browne , later became Chief Justice of the Florida Supreme Court. The Labor Day Hurricane of 1935 washed away the first deck of the lighthouse, 15 feet above the water, but the tower survived. The lighthouse is inside

476-683: The boundaries of Biscayne National Park . In June 2011, the General Services Administration made the Fowey Rocks Light (along with 11 others) available at no cost to public organizations willing to preserve them. On October 2, 2012, the National Park Service accepted ownership of the light. It is the last of the original Florida Keys offshore manned reef lights in operation, all others having been decommissioned by 2015. The original Fresnel lens has been replaced by

504-532: The channel, is located 6 nmi (11 km; 6.9 mi) southwest of Key West, between Sand Key Channel and Rock Key Channel, two of the channels into Key West, on a small sand covered reef. Hawk Channel contains an estimated 1,000 or more shipwrecks in its waters. A popular diving trail consisting of nine notable wrecks along the channel are designated as "Shipwreck Trail" under the Florida Keys National Marine Sanctuary . Although

532-583: The cold Arctic Sea and, the theory went, making Siberia and northern Canada more habitable. As part of the North American team, Canadian oceanographer Maxwell Dunbar found it "very cumbersome" to repeatedly reference millions of cubic meters per second. He casually suggested that as a new unit of water flow, "the inflow through Bering Strait is one sverdrup". At the Arctic Basin Symposium in October 1962,

560-403: The current (several km), depth (hundreds of meters), and current speed (as meters per second ). Thus, a hypothetical current 50 km wide, 500 m (0.5 km) deep, and moving at 2 m/s would be transporting 50 Sv of water. The sverdrup is distinct from the SI sievert unit or the non-SI svedberg unit. All three use the same symbol, but they are not related. The sverdrup

588-511: The development of patch reefs 3 to 6 m (9.8 to 19.7 ft) deep off of Hawk Channel. The course along the channel is partially protected by a fringing barrier reef roughly 3 to 6 mi (4.8 to 9.7 km) offshore, limiting the effects of winds bearing northwest and sheltering the passage from the direct thrust of the Atlantic and Florida Straits. The four central exchanges of South Florida coastal waters of Long Key Channel, Channel 5, Channel 2, and Moser Channel , situated perpendicular to

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616-466: The exact origins of the name remain largely uncertain, Hawk Channel has been a prominent site for birdwatching ; the prolonged bird migration in the fall season goes on from early July until late November where large flights of broad-winged hawks , as well as merlins , and peregrine falcons , are predominant during the September–October migration. Prior to the Spanish occupation of Florida ,

644-425: The motor vessel Wellwood ran aground on the upper fore-reef on Molasses Reef southeast off of Key Largo in 6 metres of water, resulting in the destruction of 5,805 square meters of living corals. The wreck remained grounded for 12 days before it was removed by the U.S. Coast Guard . Fowey Rocks Light Fowey Rocks Light is located seven miles southeast of Cape Florida on Key Biscayne . The lighthouse

672-704: The reef. In 1858, the Sombrero Key Light , the tallest lighthouse in the Florida Keys, was put in service located on a mostly submerged reef that had been referenced in old Spanish charts but had eroded away during the 19th century. The lighthouse now lies near the Sombrero Key Reef . Between 1921 and 1935, the unmanned reef lights of Molasses Reef Light, Pacific Reef Light, Hen and Chickens Shoal Light, Smith Shoal Light, and Tennessee Reef Light were erected as navigational aids and Daymarks along Hawk Channel to mark shallow hazards. On 4 August 1984,

700-469: The south in 1748. During construction of the lighthouse the workers lived on a platform built over the water to minimize the danger of transporting them and their supplies each day from the mainland. While construction was under way, on 17 February 1878 the Arratoon Apcar ran aground on the reef. The 1500 ton steamship came to rest just 200 yards (180 m) from the workmen's platform. Efforts to save

728-402: The substantial openings in the fringing reefs found 61 mi (98 km) between Alligator Reef Light and American Shoal Light . According to marine reports, the local current predominately sets fair with the channel except alongside the opening between Hawk Channel and Biscayne Bay where fairly strong crosscurrents exist most notably during an ebb tide . The channel runs systemically with

756-470: Was a first-order drum Fresnel lens which stood about 12 feet (4 m) high and weighed about a ton (tonne). The light has a nominal range of 15 miles in the white sectors, and 10 miles in the red sectors. It serves as a maker for the entrance to the Hawk Channel passage through the Florida Keys. Fowey Rocks are named after the Royal Navy frigate HMS Fowey which was wrecked on a different reef to

784-461: Was completed in 1878, replacing the Cape Florida Light . It was automated on May 7, 1975, and as of 2021 is still in operation. The structure is cast iron , with a screw-pile foundation, a platform and a skeletal tower. The light is 110 feet above the water. The tower framework is painted brown, while the dwelling and enclosed circular stair to the lantern is painted white. The original lens

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