SUBMARINE DEVELOPMENT A survey of submarine visionaries and pioneering boats
THE HISTORICAL RECORD IS AWASH with examples of early peoples seeking to explore the underwater world. In a section of the ancient Greek text Problemata, which may or may not have been written by Aristotle around 360 B.C., the author hypothesizes the use of a kind of diving bell, an inverted “kettle” filled with air to give sponge divers an underwater base of operations for extended dives. During Alexander the Great’s siege of Tyre in 332 B.C., enemy divers continually severed the mooring ropes of Alexander’s ships and set them adrift to crash into each other. Though no record of the siege mentions the use of a diving bell, a legend emerged of Alexander being lowered into the harbor in a glass barrel or jar for several minutes to observe the goings-on. For centuries thereafter, versions of this tale were celebrated in texts and paintings from Britain to India. One of the first actual uses of the diving bell was recorded by Francesco de Marchi of Bologna, who, in 1535, used a primitive one-person diving bell to explore the sunken wrecks of the Emperor Caligula’s fabled Lake Nemi ships. By now, the Western world’s leading thinkers had begun to envision a kind of underwater boat that could move under propulsion. Leonardo da Vinci, for one, claimed to have figured out how a person could remain submerged for an extended period of time – but also claimed he would never publish the details of this information “because of the evil nature of men who practice assassination at the bottom of the sea.” In 1578, seven decades after da Vinci’s death, the English mathematician William Bourne published his own idea for a submersible in the book Inventions or Devices, which included a description of “a shippe or boat that may goe under the water unto the bottome, and so come again at your pleasure.” Though he included no drawings or models, Bourne described how the craft – essentially a wooden boat covered in oiled leather – could be raised or lowered in by filling and emptying ballast tanks, and how its occupants could breathe by means of a hollow mast protruding upward. The first submersible boats to be made to Bourne’s description were conceived by Dutch physician Cornelius Drebbel, who tutored the children of King James I and served as “court inventor.” While Bourne had hypothetically solved the problems of buoyancy and air supply, Drebbel added a solution to how the boat could be propelled: A crew of oarsmen, if the boat were properly sealed and ballasted, could drive it. Few records of Drebbel’s design remain, but he built and successfully tested 86 USS DELAWARE
OAR/NATIONAL UNDERSEA RESEARCH PROGRAM (NURP) IMAGE
By Craig Collins
A 16th century painting of Alexander the Great being lowered into the harbor in a kind of glass diving bell.
