Exploration Timeline

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Exploration Timeline

Here are some of the highlights of ocean exploration through history.

1843- first modern sounding takes place at 27 degreed south and 17 degrees west

1849- Continental shelf break and continental slope are discovered

1857- a deep valley discovered by James Madison Alden in the center of Monterey Bay, now known as Monterey Canyon

1867-1868- dredging operations by Louis F. de Pourtales reveal life extending below 300 fathoms

1872- an operational wireline sounding machine is invented by Sir William Thomson

1872- the Coast Survey Steamer Hassler sails from the east to west coast and attempts deep-ocean dredging. Although the dredging line broke on every attempt, more than 30,000 specimens of sea life were collected.

1873-1876- the Challenger expedition is led by Sir Wyville Thomson. This was the first worldwide oceanographic cruise

1874-1877- the Thomson Sounding Machine is modified and renamed the Sigsbee Sounding Machine after Commander Charled D. Sigsbee, who made the modifications

1872-1878- the first bathymetric map is made as a result of high-density soundings taken in the Gulf of Mexico and the Caribbean Sea

1877- the Coast Survey Steamer Blake becomes the first ship to be equipped with a steel rope for dredging puposes

1912- the sinking of the Titanic leads to an effort to find a way to discover objects in the water foward of the bow of a moving vessel

1914- on April 17, a Fessenden Oscillator is used to reflect a signal off an iceberg and at the same time reflect an acoustic signal off the sea bottom. This marks the beginning of acoustic sea exploration

1924- The Coast and Geodetic Survey conducts the first radio acoustic ranging (RAR) operation. This is the first navigational system that can operate all the time regardless of weather conditions and doesn't need a navigator to position a vessel.

1925-1939- seamounts and guyots are discovered across the Gulf of Alaska.

1935- an automatic telemetering radio is invented. This eliminates the need for manned station ships during RAR navigation operations.

1937- the bathythermograph is invented by Athelstan Spilhaus to measure and continuously record the temperature.

1941-1945- during WWII, electronic navigation systems are developed for bombing precision. Other inventions during this time period include; deep-ocean camera systems, early magnetometers, sidescan sonar instruments, and early technology for guiding remotely operated vehicles(ROVs).

Diagram of the Sigsbee Sounding Machin

courtesy of oceanexplorer.noaa.gov