Ancient Divers—Early Attempts at Underwater Exploration
The history of underwater exploration dates back thousands of years, when early civilizations relied on freediving to gather food and valuable resources. Coastal communities in Mesopotamia, Egypt, and Greece developed breath-hold diving techniques to harvest shellfish, sponges, and pearls from the seafloor. By 1000 BC, Greek divers had refined their methods, using heavy rocks to descend to depths of approximately 30 meters, demonstrating an early understanding of pressure and buoyancy. These divers played a crucial role in commerce, supplying the Mediterranean trade with sought-after marine goods.
Beyond economic pursuits, ancient divers also contributed to military strategy and underwater salvage. In times of war, Greek and Roman navies employed skilled divers for reconnaissance, sabotage, and the retrieval of sunken cargo. Historical records suggest that Assyrian divers as early as 900 BC used air-filled animal skins to extend their time underwater, an innovation that foreshadowed later developments in diving technology. Aristotle later documented the concept of a primitive diving bell around 360 BC, marking one of the earliest recorded attempts to create an artificial air supply for underwater missions.
These early underwater endeavors laid the foundation for later technological advancements, proving that humans have long sought to conquer the depths of the sea.
Alexander the Great’s Supposed Use of a Diving Bell
The tale of Alexander the Great descending into the depths of the ocean inside a primitive diving bell is one of the more captivating legends surrounding his conquests. Though no concrete historical evidence supports this claim, the story appears in versions of the Alexander Romance, a collection of semi-mythical accounts of his life. According to these accounts, Alexander supposedly used a “glass barrel” or a “metal-framed vessel with white glass” to explore the underwater world, potentially during the siege of Tyre in 332 BCE. While this siege was a documented military campaign, the idea that he personally ventured beneath the waves remains speculative.
The concept of a diving bell was not entirely out of place in the ancient world. Aristotle, who tutored Alexander, described air-retaining devices that allowed divers to stay submerged for longer durations. Some historians suggest that the legend may have stemmed from actual underwater engineering techniques used by Alexander’s forces, such as employing divers to remove underwater obstacles. However, the more fantastical elements—encounters with sea creatures and moral reflections from the ocean floor—suggest that this story was more symbolic than factual.
Despite its mythical nature, the tale reflects humanity’s early fascination with underwater exploration. It also foreshadowed the eventual development of functional diving bells, which became a reality centuries later. Whether or not Alexander truly ventured beneath the waves, his legend continues to inspire curiosity about the ancient origins of underwater technology.
The First Military Use of Underwater Combat by Greek and Roman Divers
The idea of ancient underwater combat might conjure images of stealthy divers sabotaging enemy ships beneath the waves. While direct evidence of large-scale underwater battles is scarce, historical accounts suggest that Greek and Roman forces employed divers for military purposes—primarily sabotage, reconnaissance, and naval engineering. Greek divers, particularly those from Rhodes and other Aegean islands, were known for their ability to swim underwater for extended periods. They used weighted stones to descend quickly, a technique that allowed them to cut anchor lines or damage enemy hulls before surfacing unseen.
The Romans, inheriting Greek naval strategies, refined these underwater tactics. Historical accounts mention Roman divers conducting reconnaissance missions in harbors, assessing underwater defenses, and even planting obstacles to hinder enemy ships. Though rudimentary, these techniques foreshadowed modern naval sabotage. Additionally, ancient texts describe the use of hollow reeds for breathing while submerged, a primitive precursor to later diving technologies. While no formalized underwater combat units existed, these early military divers played a crucial role in naval warfare, influencing later developments in underwater strategy. Their ingenuity demonstrated that even in antiquity, control of the seas extended beneath the surface.
Cornelis Drebbel’s 1620 Submarine Test in the Thames River
In the early 17th century, the idea of underwater travel was more fantasy than reality. Yet, in 1620, Dutch inventor Cornelis Drebbel transformed this vision into a tangible achievement by building and successfully testing the world’s first navigable submarine in the Thames River. Working under the patronage of King James I of England, Drebbel’s creation was an engineering marvel for its time. The vessel featured a wooden frame covered in greased leather to ensure watertightness, and it was propelled by oars extending through sealed ports. Unlike later submarines that relied on mechanical propulsion, Drebbel’s craft moved thanks to a team of oarsmen rowing beneath the surface.
What made Drebbel’s submarine even more astonishing was its ability to remain submerged for extended periods. Reports suggest it could stay underwater for up to three hours at depths of 12 to 15 feet (4 to 5 meters). To achieve this, Drebbel devised a rudimentary air supply system using snorkel-like tubes that extended to the water’s surface. Some accounts even speculate that he experimented with chemical oxygen generation, possibly using potassium nitrate to produce breathable air. These innovations allowed King James I and other witnesses to observe one of the earliest demonstrations of controlled underwater navigation—a feat that must have seemed like sorcery at the time.
Despite its groundbreaking nature, Drebbel’s submarine failed to gain military interest from the English Navy. While it demonstrated the feasibility of underwater travel, naval warfare of the era relied on surface combat, and the strategic advantages of submarines were not yet fully realized. Nevertheless, Drebbel’s work laid the conceptual foundation for future submarine designs. More than a century would pass before similar underwater vessels were considered for military applications, but his pioneering efforts marked a crucial step in the evolution of underwater exploration.
The Turtle—The American Revolution’s First Submarine Attack
In the midst of the American Revolution, a remarkable invention emerged that would forever change naval warfare: the Turtle, the world’s first combat submarine. Designed in 1775 by David Bushnell, a Yale-educated inventor, this one-man submersible was built to deliver underwater explosives to British warships. The vessel, which resembled two joined tortoise shells—hence its name—was an egg-shaped wooden craft reinforced with iron bands. It operated by taking in water as ballast to submerge and expelling it to resurface, while a hand-cranked screw propeller allowed for movement beneath the waves. Bushnell’s vision was revolutionary: he sought to give the Continental Army a secret weapon capable of breaking British naval dominance.
The Turtle’s first mission took place on September 7, 1776, when Sergeant Ezra Lee piloted it toward the British flagship HMS Eagle in New York Harbor. His goal was to attach a time-delayed explosive charge to the ship’s hull. However, the attempt failed when the Turtle’s drill encountered an unexpected obstacle—iron plating instead of wood. Unable to secure the explosive, Lee was forced to retreat. Despite the mission’s failure, the Turtle demonstrated the feasibility of underwater warfare, a concept that would evolve into modern submarine combat.
Although the Turtle was deployed in subsequent missions, none achieved their intended success. Eventually, the vessel was lost when the British sank the sloop transporting it on October 9, 1776. While its ultimate fate remains uncertain, Bushnell later claimed to have recovered it. Regardless, the Turtle’s legacy was profound—it laid the groundwork for future submarine development, proving that underwater stealth attacks were not only possible but a strategic advantage.
How Early Underwater Missions Paved the Way for Modern Naval Warfare
The history of underwater exploration is deeply intertwined with the evolution of naval warfare. From ancient divers conducting sabotage operations to the development of submarines, each innovation laid the groundwork for the sophisticated underwater combat strategies used today. The earliest recorded military use of underwater missions dates back to Greek and Roman divers, who employed rudimentary breathing devices to cut anchor lines or infiltrate enemy ships undetected. These early tactics demonstrated the strategic advantage of underwater stealth, a principle that remains central to modern submarine warfare.
The technological progression of underwater equipment significantly influenced naval capabilities. The diving bell, first described by Aristotle and later refined by Edmund Halley in 1691, allowed divers to stay submerged for extended periods, facilitating salvage operations and reconnaissance missions. By the 19th century, surface-supplied diving suits, such as Augustus Siebe’s standard diving dress, enabled deeper and longer underwater excursions, crucial for military engineering projects like underwater fortifications and mine clearance. These advancements directly contributed to the development of modern combat diving units.
Perhaps the most pivotal breakthrough came with the advent of submarines. Cornelis Drebbel’s 1620 submarine, though rudimentary, proved that manned underwater navigation was possible. This concept evolved into fully operational military submarines, with the American Revolution’s Turtle marking the first recorded underwater attack. While the Turtle’s mission was unsuccessful, it demonstrated the potential for submersible vessels in warfare. Today’s nuclear-powered submarines, equipped with advanced stealth technology and ballistic missile capabilities, owe their existence to these early innovations.
Beyond combat, early underwater missions also played a role in naval intelligence and strategy. The mapping of ocean floors, pioneered by expeditions like the HMS Challenger in the 1870s, provided crucial data for submarine navigation and underwater warfare tactics. The ability to conduct covert operations beneath the surface has since become a cornerstone of modern naval strategy, with submarines now serving as critical assets for surveillance, reconnaissance, and deterrence.
In essence, the evolution of underwater missions from ancient divers to modern submarines illustrates a continuous trajectory of technological and strategic advancements. Each development, from diving bells to submersibles, contributed to the sophisticated underwater combat and intelligence-gathering techniques employed by navies worldwide today.
The Evolution of Underwater Exploration from Ancient Times to Today
Underwater exploration has progressed from rudimentary breath-holding techniques to sophisticated deep-sea submersibles, reflecting humanity’s relentless curiosity about the ocean’s depths. The earliest recorded instances of underwater activity date back to ancient civilizations, where freedivers harvested pearls, sponges, and seafood. Greek and Roman divers, for instance, used heavy stones to descend quickly, a primitive yet effective method for retrieving valuable marine resources. Aristotle described an early form of a diving bell in the 4th century BCE, marking the first known attempt to extend human endurance underwater.
The Renaissance and Enlightenment periods saw significant advancements in diving technology. In 1620, Cornelis Drebbel tested the first operational submarine in the Thames River, proving that humans could traverse beneath the water’s surface for extended periods. The 17th and 18th centuries further refined diving bells, with figures like Edmund Halley introducing air-replenished models to facilitate underwater salvage operations. By the 19th century, surface-supplied diving helmets and suits, pioneered by Augustus Siebe and the Deane brothers, enabled divers to work at greater depths for longer durations.
The 20th century revolutionized underwater exploration with the invention of self-contained breathing apparatuses. Jacques-Yves Cousteau and Émile Gagnan’s Aqua-Lung in 1943 granted divers unprecedented autonomy, paving the way for military, scientific, and recreational diving. Submersibles like Alvin, first deployed in 1964, expanded deep-sea research capabilities, leading to discoveries such as hydrothermal vents and previously unknown marine species. The latter half of the century also saw experiments with underwater habitats like Sealab and Conshelf, proving that humans could live beneath the ocean for extended periods.
Today, underwater exploration continues to evolve with cutting-edge technologies. Autonomous underwater vehicles (AUVs) and remotely operated vehicles (ROVs) now conduct deep-sea surveys without human presence, while advances in mixed-gas diving allow researchers to explore depths once deemed unreachable. Aquarius, the world’s only undersea research station, remains operational, providing critical insights into marine life and climate change. From ancient Greek sponge divers to modern oceanographers mapping the seabed, humanity’s journey into the deep is far from over.
