When we think of submarines, sleek steel hulls and nuclear reactors come to mind, but the story began long before modern engineering. In this roundup of the 10 ancient precursors that set the stage for today’s underwater vessels, we travel back over two millennia to discover inventive minds, daring experiments, and the early devices that hinted at the future of submersible travel.

10 Nautilus, 1800

Long before Jules Verne’s famous novel, the 1800 Nautilus—named by Verne himself—was already prowling the seas. Built in France, this copper‑clad craft featured a collapsible wooden mast, a sail, and a hand‑cranked propeller for underwater thrust. Its designer, American Robert Fulton, better known for his steamboats, saw the sub as a tool to end naval warfare, pitching it to France, Britain, and the United States. Yet, despite its self‑propelled bomb, no navy showed interest; a French admiral even quipped it was fit only for “Algerians or pirates.”

9 “Turtle”, 1776

The first combat‑used submarine was American engineer David Bushnell’s “Turtle” during the Revolutionary War. Intended to attach time‑delay mines to British vessels, it failed all three attempts. This pear‑shaped wooden hull, reinforced with iron bands, measured 2.3 × 1.8 m and held a single operator, who powered it by hand. After the project’s collapse, Bushnell vanished to Georgia, changed his name to Bush, and became a doctor, apparently to escape the “Turtle”’s ignominious reputation.

8 Improved Diving Bell, 1775

By the late 18th century, the diving bell was a proven technology, yet innovators still saw room for upgrades. Edinburgh confectioner Charles Spalding, spurred by a lost cargo ship, refined the bell in 1775. His enhancements added balance weights for stability, a signaling rope system, a viewing window, and rope‑based seating. Though he successfully dove to recover wreckage, he never reclaimed his goods. Awarded by the Society for the Encouragement of Arts, Manufactures and Commerce, Spalding continued diving until his fatal descent on the Belgioso wreck in Dublin Bay in 1783.

7 Morel, 1720

The world’s first military submarine emerged in 1720 under Russian carpenter Yefim Nikonov. Dubbed the Model but misnamed “Morel” by a clerk, this six‑meter‑long wooden barrel, reinforced with iron hoops and fitted with flamethrowers, was powered by oarsmen in diving suits. Water entered via ten tin plates into leather bags to submerge, and a copper piston pump expelled it for surfacing. After a successful prototype dive, a second trial saw it fail to resurface, yet the tsar still backed the project. Unfortunately, after Peter the Great’s death, funding vanished, and a 1727 test ended in disaster, leading to Nikonov’s banishment and a two‑century hiatus in Russian submarine development.

6 Halley’s Diving Bell, 1691

Edmond Halley, famed for his comet, is credited with advancing the diving bell in 1691. His design allowed divers to remain underwater for up to an hour and a half at 20 m depth, thanks to a system that replenished air from weighted barrels via internal valves. Later, French mathematician Denis Papin improved this with continuous air supply through bellows and a pipe. Halley also fashioned a mini‑bell helmet linked by a gut‑filled air hose, hoping divers could “go out of the diving bell, and stay in the water as long as they pleased.” However, he underestimated pressure effects, describing ear pain as “as if a quill had been thrust into them,” prompting later developments like John Lethbridge’s armored diving suit.

5 Margarita Diving Bell, 1625

Predating Halley’s bell by nearly three‑quarters of a century, the Margarita diving bell earned its name from the sunken Spanish galleon Santa Margarita. Archaeologists long mistook its saucer‑shaped copper cap for a fish‑cooking device, but recent research identified it as a 700‑pound bell designed in 1606. Measuring 1.2 m tall and 0.9 m wide, it featured a tube supplying fresh air from the surface. This artifact, described as the “rarest technological treasure,” stands as the oldest solid evidence of a historically recorded diving bell.

4 Drebbel’s Submarine, 1620

Dutch physician Cornelis Drebbel is credited with the world’s first navigable submarine, built in London for King James I. Though details are scarce, the vessel resembled a reinforced rowing boat wrapped in leather, propelled by six oars on each side that passed through watertight sleeves. Between 1620 and 1624, Drebbel successfully navigated the Thames, typically reaching depths of up to 15 ft. Submersion was controlled by filling and emptying pigskin bladders with surrounding water, linked to pipes and ropes for operation. Air tubes extending to the surface allowed hour‑long dives, and even the king reportedly rode aboard.

3 Bourne’s Submarine, 1578

Decades before Drebbel, English mathematician William Bourne drafted a submarine concept in his 1578 work “Inventions, or, Devises.” His design featured a wooden frame covered in leather, powered by oarsmen inside. Though never built, Bourne secured patronage from English aristocracy—earls, lords, and an admiral—raising hopes for construction. Unfortunately, he died four years later, never witnessing Drebbel’s later claim to fame.

2 Lake Nemi Diving Bell, 1531

The earliest reliably documented diving bell may be the one employed to salvage Caligula’s sunken barges in Lake Nemi near Rome. After a failed 1446 attempt by Genovese divers, a cardinal commissioned a sophisticated bell. Its exact mechanics remain mysterious, but it featured an air‑expulsion system and a fresh‑air supply, allowing divers to work until exhaustion rather than suffocation. Despite its modest size, dives could last up to two hours, showcasing advanced engineering for the era.

1 Bathysphere, 332 BC

For the Siege of Tyre, Alexander the Great is said to have commissioned a glass barrel—some call it a bathysphere—to scout underwater defenses. Made of white glass and reinforced with metal bands, this 600‑foot‑long chain‑lowered vessel held Alexander and two companions. Aristotle recorded their awe at the bright lights inside, yet Alexander felt melancholy, later reflecting that “the world is damned and lost; the large and powerful fish devour the small fry.” While its exact nature (diving bell vs. submersible) is debated, Aristotle’s “Problemata” describes a similar air‑filled kettle used to extend divers’ underwater time, illustrating early attempts to overcome pressure and breathlessness.

World War II was marked with two great submarine campaigns. The German Navy used its U-boat fleet to attempt to deny Great Britain the war materials and supplies necessary for it to continue to prosecute the war. After the American entry into the war the United States Navy carried out a submarine campaign against Japan tasked with accomplishing the same goals against that island nation. Both sides practiced unrestricted submarine warfare. That meant submarines would torpedo ships of their enemies without warning.

Both the Americans and Germans produced submarine officers noted for exceptional skill and professionalism. The US Navy’s submarines sank over 5.5 million tons of Japanese shipping during the war. The German U-boats destroyed 14.1 million tons of Allied shipping over the course of the war, nearly 70% of all Allied losses for all theaters of the global conflict. Both services produced men with remarkable records of destruction inflicted on the enemy. Total ships and tonnage sunk vary according to sources, but here are the top 10 submarine aces of World War II.

10. Slade D. Cutter: 142,300 tons (21 ships)

Before he became a submarine ace in World War II, Slade Cutter starred on the football field for the US Naval Academy Midshipmen. An All-American player at Navy in the 1930s, Cutter was inducted into the College Football Hall of Fame in 1967. After graduating in 1935, he served in the battleship USS Idaho. He entered the submarine service in 1936, and by 1941 was serving as the executive officer in USS Pompano. After three war patrols on the submarine he was assigned to a submarine still under construction, USS Seahorse, SS-304, as the executive officer.

After Seahorse completed its first war patrol its commanding officer was relieved for displaying a lack of aggression against the enemy. Cutter was assigned to command the vessel in October, 1943. His four war patrols led to the sinking of over 142,000 tons of Japanese shipping, including an enemy submarine I-274. Contrary to Hollywood depictions, submarine on submarine attacks during the war were relatively few in number.

Cutter remained in the Navy after the war, retiring as a Captain in 1965. For his service in World War II he received the Navy Cross, the service’s second highest award, for each of his four war patrols in Seahorse. He never reached flag rank, according to some because of his ill-concealed disdain for deskbound senior officers, including Hyman Rickover, which eliminated him for consideration for command in the emerging nuclear navy.

9. Eugene Fluckey: 179,700 tons (25 ships)

Eugene Fluckey graduated from Annapolis in 1935 and began his career in submarines in 1938. The outbreak of World War II found him serving in USS Bonita, in which he completed five war patrols before being assigned to command USS Barb, SS-220. Fluckey commanded the submarine during seven war patrols conducted between March 1944, and the end of the war in August 1945.

On one occasion, Fluckey put a party of men ashore in the Japanese home islands, charged with the destruction of a train. As commanding officer of USS Barb, Fluckey earned four Navy Crosses and the Medal of Honor. Following an attack on a Japanese convoy in 1945, Barb set a record for speed in a submarine, 23.5 knots, as he withdrew from the pursuit of Japanese destroyers. He remained in the Navy following the war, retiring as a Rear Admiral in 1972. Known as “Lucky” Fluckey, he wrote a well-received book about the war patrols aboard Barb in 1992, Thunder Below!

Fluckey commanded Barb when it became the first submarine to deploy rockets against the enemy, bombarding targets in Japan in June and July 1945. He thus helped usher in an entirely new use of the submarine in warfare. Today’s nuclear submarines carry both ballistic missiles and cruise missiles for use against targets on both land and sea.

8. Heinrich Lehmann-Willenbrock: 183,253 tons (25 ships)

Among the four U-boats commanded by Heinrich Lehmann-Willenbrock during World War II was U-96. U-96 was later the subject of the film Das Boot. During his three patrols in U-96, Lehmann-Willenbrock sank over 120,000 tons of mostly British shipping, including three troopships. Primarily operating out of the submarine pens at Brest (St. Nazaire), Lehmann-Willenbrock rose to command the 9th U-boat Flotilla. In September, 1944, as Allied troops threatened to capture Brest, Lehmann-Willenbrock assumed command of U-256 and escaped to Norway, despite the overwhelming air and naval superiority of the Allies.

Lehmann-Willenbrock surrendered to the British in 1945, who held him captive for a year before he returned to Germany. He then returned to the sea, serving in and commanding merchant vessels. When the German merchant vessel and icebreaker Otto Hahn, a nuclear powered ship, became operational in 1969, it was he who commanded. He served as a consultant during the filming of Das Boot, in which Jurgen Prochnow played the unnamed commander of U-96 during a war patrol in 1941.

Lehmann-Willenbrock served in operational U-boats throughout the war, from 1939 to 1945. That he survived is remarkable, given the casualty rates suffered by that branch of the service. He died in Bremen, the city of his birth, on April 18, 1986.

7. Herbert Schultze: 183,482 tons (28 ships)

On September 11, 1939, a German U-boat transmitted a radio message addressed to First Lord of the Admiralty Winston Churchill. The message informed him of the sinking of the British merchant ship Firby, gave its last position, and requested they pick up survivors in the ship’s boats. A few days later the U-boat, commanded by Herbert Schultze, stopped another British vessel. He let the ship continue on its way provided it rescued the survivors from Firby and did not radio the position of his ship. It was an act of chivalry unmatched in a campaign of unrestricted submarine warfare.

Schultze commanded U-48 on eight war patrols from September, 1939, until July, 1941. After his stunning successes at sea he served in staff positions, eventually commanding the Murwik Naval School. He remained in that assignment until the war’s end. He eventually returned to active duty with the West German Navy in 1956, retiring in 1968. During his relatively brief service as an active U-boat commander he achieved one of the highest success rates of the war.

He also achieved a level of notoriety within the German high command for his complaints regarding manufacturing defects which produced numerous failures in German torpedoes. Health issues plagued Schultze as well. For whatever reason, from July 1941 through the end of the war, one of Germany’s best U-boat commanders remained ashore, an immeasurable benefit for the Allies.

6. Heinrich Liebe: 187,267 tons (34 ships)

When World War II began in September, 1939, Heinrich Liebe was one of the most experienced U-boat officers in the service. In command of U-38, he claimed his first victim on September 6. From that date until June, 1941, he sank 34 Allied ships, all of them merchantmen, reaching a total of nearly 190,000 tons.

By the summer of 1941 Liebe was among the most highly decorated German U-boat commanders. He was also among the most senior, both in time of service and rank. As more and more U-boats left German shipyards the men to command them were younger and less experienced. In July, 1941, Liebe left U-38 for a staff position with the German Naval High Command. His nine war patrols, all of which were successful, comprised a total 333 days at sea.

On average, he sank an Allied ship every ten days during an at sea war career of 21 months. On his last patrol alone, from April to June, 1941, he sank 8 ships, for over 47,000 tons. As with Heinrich Liebe, his promotion to a staff position was a blessing for the Allies.

5. Gunther Prien: 194,103 tons (31 ships)

Gunther Prien was the author of a submarine exploit of legendary proportions. In October, 1939, under orders from Rear Admiral Karl Donitz, he took his submarine into Scapa Flow, the main anchorage of the Royal Navy’s Home Fleet. There he sank the British battleship Royal Oak, which carried over 800 men to their deaths, and successfully eluded detection while escaping. When Prien returned to Germany on October 17 it was to instant celebrity.

He became the first U-boat commander to be awarded the Knight’s Cross of the Iron Cross. The German propaganda ministry called him “The Bull of Scapa Flow”. Prien had an image of a snorting bull painted on the conning tower of U-47. Even Winston Churchill acknowledged his attack as “a feat of professional skill and daring”. By February, 1941, Prien had completed 9 war patrols, with 29 ships sunk. On his tenth, Prien was lost at sea after another two sinkings to his credit. The official cause of his loss has never been determined.

Prien is a controversial character, with some calling him an unrepentant and fervid Nazi, while others claiming he supported German resistance. His war career lasted less than 18 months, making him one of the most successful submarine aces of the war.

4. Erich Topp: 197,460 tons (35 ships)

Erich Topp commanded four different U-boats during the Second World War. The first, U-57, sank after colliding with a Norwegian freighter (Norway was neutral at the time) in September, 1940. Topp had been in command just three months, and already had credit for six sinkings. He then assumed command of a new construction, U-552. On October 31, 1941, Topp and U-552 were on patrol in the North Atlantic when they encountered the US Navy destroyer Reuben James.

Although the United States was officially neutral, Topp attacked and sank Reuben James when the American ship approached the submarine. Only 44 of the 159 men aboard the destroyer survived. Reuben James was the first American ship sunk by enemy action during World War II. Later, in 1942, Topp sank several ships off the east coast of the United States, in sight of land in many cases. It was a period which the U-boat skippers called the Second Happy Time, as sinkings of Allied ships increased with America’s entry into the war.

Topp was promoted into staff jobs in late 1942, having completed nine war patrols, sinking nearly three dozen ships. He returned to command two additional U-boats in late winter, 1945, though neither completed a patrol. Post-war positions included a commission in the West German Navy and with NATO. He also served as a consultant for the computer game Silent Hunter II. He died in Germany in 2005, at the age of 91.

3. Wolfgang Luth: 221,981 tons (47 ships)

Wolfgang Luth completed his first war patrol in 1939, as First Officer under Heinrich Liebe. In December of that year Luth received command of U-9. While in command of that U-boat he attacked and sank a surfaced French submarine, Doris, off the coast of Holland. In 1940 he took command of U-138, with which his sinkings continued to increase, reaching well over 55,000 tons by autumn. Luth later commanded U-43, and later U-181. In 1943, he departed on a patrol in the Indian Ocean and along South Africa, which ultimately lasted 205 days, the second longest patrol of any submarine during World War II.

In total, Luth completed 15 war patrols, surviving depth charging by escort ships, bombing and strafing runs by enemy aircraft, and bombardment by armed merchant ships. He logged over 600 days at sea during the war. In 1944 he assumed new duties at Murwik, and he remained there when the British occupied the area in May, 1945. On the evening of May 15 he was returning to the academy after drinking heavily in local bars. A sentry called out to him to halt.

Either Luth did not hear the German sentry’s challenge or was too drunk to obey it, and the sentry shot him, once, in the head. The occupying British authorities allowed the Germans to give Luth a state funeral. The sentry was cleared of any wrongdoing by both British and German authorities.

2. Richard O’Kane: 227,824 tons (33 ships)

Richard H. O’Kane served in 10 war patrols in the Pacific during World War II. In five he was the executive officer of USS Wahoo under Dudley “Mush” Morton. Subsequently he commanded USS Tang on five more. O’Kane assumed command of Tang in October, 1943. Before the submarine sank itself via a faulty torpedo, it destroyed 33 Japanese ships. It also served as a lifeguard during aerial operations. On one such mission, Tang rescued 24 American airmen.

In October, 1944, Tang was involved in a night surface action when one of its Mark 18 torpedoes went on a circular run. Unable to evade, Tang was struck by the faulty weapon and sank. Only nine men survived, including O’Kane, and were taken prisoner by the Japanese. O’Kane was held for a time at Ofuna, without notification to the Red Cross he was a prisoner. Later he was transferred to the Omoru Prisoner of War Camp. Among his fellow prisoners was Greg “Pappy” Boyington of the Black Sheep Squadron.

Richard O’Kane remained in the Navy following the war, retiring in 1957. Among the many legends surrounding his career is his prowess at the game of cribbage. O’Kane is said to have once scored a 29 in one hand, against odds of more than 200,000 to one. His personal cribbage board (though not the board on which the score was recorded, which went down with Tang) is assigned to the wardroom of the oldest attack submarine in the US fleet to this day.

1. Otto Kretschmer: 274,333 tons (44 ships)

Otto Kretschmer reigns as the “Ace of Aces” for submarine warfare. His career of destruction in the Atlantic began in 1939. His early patrols were short in number of days at sea, and relatively unsuccessful. By early 1940 he had developed his preferred means of attack. Kretschmer chose to attack while surfaced whenever possible, at night, and by firing just one torpedo at each target rather than salvoes. In April 1940, Kretschmer took command of U-99. When possible, he took U-99 inside the enemy convoys, allowing him to attack in any direction before diving the boat to escape.

In December, 1940, Kretschmer completed his 15th war patrol. In March 1941, he attacked a convoy escorted by British destroyers. It was part of the same action which cost the Germans Gunther Prien. Kretschmer’s attacks sank five ships and forced the abandonment of another, which was destroyed by the escorts, but the severity of the British depth charging forced Kretschmer to surface his ship, signal it was sinking, and order his crew to abandon ship. U-99 was scuttled by the Germans, and Kretschmer became a prisoner of war.After being held in Britain for some time for interrogation he spent the rest of the war in a prisoner of war camp in Canada. He was released on December 31, 1947, and returned to West Germany. In 1955 he joined the West German Navy. He worked with NATO, retiring in 1970 with the rank of admiral. Ironically, Otto Kretschmer died following an accident on a boat, where he fell down some steep steps, suffering fatal injuries. He was 86, on a cruise celebrating his 50th wedding anniversary.