Submarines
Do you know how a submarine is different from a submersible? A submarine is a special kind of boat that can travel underwater by itself. It doesn't need help from other ships because it can make its air and power on its own. On the other hand, a submersible is a small vehicle that can also go underwater, but it needs a bigger ship to help it get air and power, so it can't stay underwater as long as a submarine can.
The first known submersible was built in 1620 by Cornelius Drebbel. It was moved by oars that rowed underwater. Even though this vehicle was first made for exploring under the sea, people soon realized it could be used in war. In 1648, Bishop John Wilkins said that this kind of boat could be useful in fighting against enemy ships because you could sneak up on them underwater.
The first military submarine was made over 100 years later. David Bushnell designed The Turtle in 1775. The Continental Army used it during the American Revolutionary War. Even though The Turtle had help from a support ship, it could still make its own air and power, which makes it a real submarine. It was powered by hand-cranked propellers and looked like a turtle. The Turtle could hold one person, travel at about three miles per hour in calm water, and stay underwater for about thirty minutes. It was used to try and attack a British ship in New York Harbor, but the mission did not succeed, and later The Turtle was destroyed. However, it is still remembered as the first submarine used in a war.
Another important submarine was the Sub Marine Explorer, made by Julius H. Kroehl between 1863 and 1866. It was built for the North during the American Civil War but was not used because the war ended. Later, it was used to collect pearls in Panama, but people didn't understand the health risks back then. Kroehl died from a condition called decompression sickness, which happens when divers come up to the surface too quickly. In 1869, after more crew members died, people stopped using the submarine.
During World War I, submarines were used a lot more. New engineering advances like using diesel and electric power made them better for warfare. The Germans had a submarine called the U-Boat, which was quite effective. Some people think U-Boats were more like submersibles because they mostly stayed on the surface and only went underwater to attack. During World War I, U-Boats sank more than 5,000 Allied ships, including the Lusitania, which is one reason America joined the war.
In World War II, Germans used U-Boats again. Even though they caused problems for British ships, improvements in technology, like radar and sonar, made them less effective. The U.S. also had submarines that they used with great success. Even after the attack on Pearl Harbor damaged many U.S. ships, the submarines survived and went on to cause a lot of damage to Japanese ships. U.S. submarines were only about 2 percent of the Navy, but they destroyed over 30 percent of the Japanese Navy, becoming one of the most powerful weapons.
Today, modern submarines are powered by nuclear reactors. This type of reactor gives them a lot of power, so they don’t need to come up to the surface for a long time. They can travel fast and stay underwater for long periods because the nuclear reactor provides energy for their entire life, often over 25 years. The only reason they need to come up is to get more food and water for the crew. Even back in 1648, Bishop John Wilkins couldn't have imagined submarines would become this powerful.
