USC&GS George S. Blake

USC&GS George S. Blake, in service 1874–1905, is, with the U.S. Fish Commission steamer Albatross, one of only two US oceanographic vessels with her name inscribed in the façade of the Oceanographic Museum (Musée Océanographique), Monaco due to her being "the most innovative oceanographic vessel of the Nineteenth Century" with development of deep ocean exploration through introduction of steel cable for sounding, dredging and deep anchoring and data collection for the "first truly modern bathymetric map of a deep sea area."

Construction George S. Blake, a steam and sail schooner, was built at a cost of $84,600 in 1874 by E. J. Fardy, Baltimore, Maryland with dimensions of 148 feet 0 inches (45.11 m) length with 26 feet 6 inches (8.08 m) beam and draft of 11 feet 8 inches (3.56 m). It was named after late United States Naval Academy Superintendent George S. Blake.

Notable events

Among the notable discoveries linked to the ship was the definition of bathymetry proving an unexpected at the time and unusual feature of the United States continental slope, now named for the ship as the Blake Plateau. Initial findings of such a plateau were found in June 1880 during investigations of the Gulf Stream. During her first survey season, starting in June 1874, George S. Blake was being used to test deep sea equipment designed by Sir William Thomson, the Thomson Sounding Machine (also known as the Kelvin sounding machine), as modified by Commander Belknap, USN and to bring up specimens from 2,144 fathoms (12,864 ft; 3,921 m) in the Gulf of Maine. By the time the ship reached the Gulf of Mexico in 1875 under the command of Lieutenant Commander Charles Dwight Sigsbee, USN the ship was using a modification of the Thomson sounding machine designed by Sigsbee, known as the Sigsbee sounding machine that was the standard wire sounding device for fifty years, and with the shot release device first tested the previous year with Sigsbee attached to the survey party.

The Gulf of Mexico In addition to simple sounding, dredge samples, current measurements and even water column sampling with a "water cup devised" by Sigsbee, temperatures and other observations were made during surveys. By the close of the Gulf of Mexico surveys in 1876 the sounding lines and concurrent sampling by George S. Blake led to the assessment that "the data gathered this season may afford means for developing the main peculiarities of this large body of water" During 1876 the ship became involved in work undertaken to understand the Gulf Stream and John E. Pillsbury designed the Pillsbury current meter when he was George S. Blake's executive officer in 1876. Though other work was done in the stream, that meter was not used until Pillsbury took command of the ship in 1884. It was in association with that work that the deep soundings across the current would reveal the Blake Plateau.

By 1878 the Gulf Stream and Gulf work would see the addition of Alexander Agassiz, who joined the ship in December 1877 in Havana, with dredges and trawls for deep biological sampling. By June 1879 the ship had been completely refitted for deep sea sounding and dredging work. Under the command of John Pillsbury, from 1884 to 1889, the ship intensified Gulf Stream work with current measurements using his device, sounding lines from shore to beyond the current, temperatures and biological sampling.

Atlantic-Caribbean passages In November 1878, Lieutenant Commander Sigsbee had completed deep surveys of the Gulf of Mexico and turned over command to Commander John R. Bartlett, USN Bartlett exploited Sigsbee's development of the Sigsbee sounding machine and George S. Blake's refit to survey with Professor Agassiz in company for biological sample dredging, in the Windward Passage and the Caribbean. Agassiz left the ship at Barbados, reached March 1879 with malaria aboard, the dredging equipment unrigged and sounding lines run in the passages of the Windward Islands where it was noted "the channels thus developed seem to be merely depressions in a range of partly submerged mountains" while current measurements began to reveal actual circulation patterns in that part of the Atlantic. In his own report Agassiz noted "One of the most interesting results reached by this year's cruise is the light thrown upon the former extension of the South American continent by the soundings taken while dredging, and those subsequently made in the passages between the islands by Commander Bartlett. Those together with soundings already known, enable us to trace the outline of the old continent ... and thus obtain some intelligible, and at the same time trustworthy, explanation of the peculiar geographical distribution of the fauna and flora of the West India Islands."

The Gulf Stream and Blake Plateau

By 1880 George S. Blake current data was supporting Bartlett's theory that "much of the supply for the Gulf Stream passes near the eastern end of Cuba." With Gulf Stream work coming to the fore the next season, a new electrical apparatus for recording temperatures was installed. After a northern season with Agassiz again aboard for dredging on Georges Bank, the ship went into winter lay up before setting out from Providence, Rhode Island 4 May 1881 for work in the Gulf Stream, described as:

The general limits of work executed during May and June are between Jupiter Inlet, Florida and Currituck Light House, North Carolina, between which points lines of soundings normal to the coast were run, extending across the Bahama Banks and, after leaving those banks, including the whole area swept by the Gulf Stream. With Agassiz collecting biological samples and examining the Gulf Stream running from Cape Romain eastward, taking frequent soundings, Bartlett noted "depths on this line were unexpectedly small, the axis of the Gulf Stream being crossed before a depth of three hundred fathoms (1,800 ft; 550 m) was found", with a bottom of "hard coral" and little life. This was early indication of the plateau that would in the future carry the ship's name, and by 1882 Commander Bartlett had described the plateau in considerable detail:

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