TECHNOLOGY > HISTORY OF SIDE SCAN SONAR

Side scan sonar technology was developed in the early 1960's by Dr. Harold Edgerton at the Massachusetts Institute of Technology. Edgerton, an MIT electrical engineering professor, had been developing high-speed flash photography since the 1930's. He discovered that photography was not best suited to the murky conditions underwater so applied the electronic principles from flash tubes to acoustics. By sending "flashes" of acoustic energy into the water and recording the reflections, Edgerton could tow his sonar device behind a vessel and create a continuous image of the seafloor.

Detail from Self-Portrait in Lab, 1942 by Harold Edgerton © The Harold E. Edgerton 1992 Trust

In 1963, Edgerton used an early side scan sonar system to find the sunken Vineyard Lightship in Buzzards Bay, Massachusetts. From 1963-1967, a team lead by Martin Klein at Edgerton, Germeshausen & Grier (later EG&G, Inc.) developed the first successful towed, dual-channel commercial side scan sonar system. The sonar was used to help Alexander McKee find King Henry VIII's long-lost flagship Mary Rose in 1967.

Edgerton made many expeditions around the world using his side scan sonar devices to search for shipwrecks and even the Loch Ness monster. In 1975, Edgerton and Jacques Cousteau, the famous French underwater explorer, used side scan sonar to discover the sunken wreck of HMHS Britannic in the Kea Channel in the Aegean Sea. The Britannic, a White Star ocean liner turned British hospital ship, had sunk during the First World War on November 21st, 1916 and is now one of the most famous shipwrecks in the world.

Original side scan technology produced images on paper rather than a computer screen. These early paper records were produced by a thermal plotter that burned the sonar image onto a scrolling paper record. By the 1980's, commercial systems using newer, cheaper computer systems could convert the analogue scan into a digital scan displaying the images on a computer screen and storing data on computer hard drives.

By 1985, advances in submersible, video and side scan sonar technology helped Dr. Robert Ballard discover the wreck of HMHS Britannic's legendary sister ship RMS Titanic at a depth of 3,800 meters (12,467 feet) in the North Atlantic. Ballard has discovered many other shipwrecks including the German battleship Bismarck in 1989.

Modern advances in acoustics and computer systems have made side scan sonar a very powerful seabed imaging device. Digital mosaics of the seafloor, referenced with GPS location coordinates, can now be created with advanced software applications and stored on computer for future reference.

Today, side scan sonar is used for a wide variety of commercial, military and leisure applications including offshore pipeline location and survey, law enforcement search and recovery operations, marine archaeology, shipwreck hunting and fish finding to name but a few.

Read about some of the StarFish Seabed Imaging Applications using the very latest side scan technology.