National Submarine Day 2022: Significance, Interesting Facts

National Submarine Day is celebrated on April 11 each year to commemorate the purchase of the U.S. Navy's first modern submarine, the USS Holland.

It was on this day in 1900 when the U.S. Navy acquired the submarine. Designed by Irish immigrant John P. Holland, the submarine was propelled by gasoline on the surface and by electricity when it's submerged, noted the Library of Congress (LC).

Not only is the USS Holland a historic submarine as the U.S. Navy's first modern commissioned submarine, but it also served as the "model" for other modern submarines.

"By the eve of World War I, the Holland and Holland-inspired vessels were a part of large naval fleets throughout the world," according to the LC.

On this day, we don't just commemorate the historic role of the USS Holland, but also the key roles that submarines have played in battles at sea. It also gives people a chance to have a closer look at the rather mysterious world of submarines.

To celebrate the occasion, people may pay a visit to a Navy museum, or perhaps even take a tour of a real submarine. They may also take this time to learn a thing or two about the unique watercrafts.

Let's have a look at some interesting submarine facts. (Courtesy: the U.S. Navy, the Library of Congress, Britannica, National Today and Kidadl)

There were proposals for such underwater boats since the 1500s. They became more common in the nineteenth century.
To stay on the surface, submarines have ballast tanks that contain air to help keep them afloat. But when it's time to submerge, the ballast tanks release the air and the seawater rushes in.
Women weren't allowed on submarines in part because of the limited privacy aboard the craft, but the ban was lifted in 2010.
Today's submarine force is said to be the "most capable" in the world and in U.S. Navy history.
Submarines use sonar to detect obstacles as well as other submarines. This is similar to the bats' echolocation.
The submarine was first used in warfare during the American Revolution via the one-man craft called the Turtle. It was made of wood and shaped like a walnut.
Submarines aren't just for military use. They can also be used for salvage missions and deep-sea explorations.