Submarines

I don't know exactly, but i can say that they were in use by the second world war. According to Wikipedia, they were also used in world war one, so that would date them in the early 1900s.

Ans 2 - The original submarine idea was put into practice in 1776 by David Bushnell. His Turtle operated during the Revolutionary war. Modern day submarines as we know them started to take shape around 1890 and since then have continuously evolved.

Submarines were invented primarily to destroy enemy ships in war, but initially they were considered underhanded by most naval officers because they were meant to attack without warning. The evolution of the submarine in wartime due to less restricted naval thinking by others helped changed that viewpoint forever.

While Submarine roles are continuously being redefined over the course of their nearly 400 year old use, as technology has evolved, their primary roles over the past 100 years have included:

Anti-ship warfare

Anti-Submarine Warfare

Radar Picket

Land Attack (Nuclear and Conventional )

Strategic Deterrence

Covert Intelligence

Covert Operator Insertion & Recovery

Covert Rescue

Search & Rescue

Mine Laying

Battle / Task Group Escort

Convoy Escort

Quick-Response to World Conflicts (submarines can get into position faster than surface vessels and undetected)

Naval & Scientific Research

Detection, Documentation, and Salvage Assistance of Naval Artifacts/Wreckage

Sailors have always dreamed of traveling under the ocean surface - Leonardo Da Vinci, an inventor of many war machines of his time, drew some of the first submarine concept designs, but they weren't put to practical use until many years later. They were eventually conceived as a craft that could sneak up on its target and sink it by means of an explosive charge. Originally, that was meant to be attached somehow, then detonated by means of a timed device. David Bushnell, inventor of the submarine Turtle, the first submarine used in combat during the Revolutionary War (but not successfully) proved that gunpowder could be detonated underwater. Unfortunately, the Turtle wasn't sufficient enough in power and design to overcome the problems with his concept of attack, boring a hole into the side of a ship and planting a charge.

The success of the submarine as a weapon finally came to pass with the Confederate submarine H.L. Hunley, which successfully planted its spar torpedo (an explosive charge on the end of a long pole attached to the submarine) into the Union sloop-of-war USS Housatonic in Charleston Harbor (South Carolina). The Hunley crew then detonated it by remote line (150' rope) as it backed away. Recent evidence found after analyzing the salvaged wreck shows that it did not sink from flooding damage caused by the explosion as previously thought; after signaling Confederate forces at her base on Sullivan's Island that the mission was successful, her crew apparently died from lack of oxygen as she was attempting to return to base after sinking the Housatonic in Charleston Harbor.

Submarine warfare evolved early in the 20th century as an anti-shipping weapon, meant to deny an enemy the means of resupplying itself. Up until the advent of airplanes, shipping was, and still is today, the primary means of moving large amounts of materials and supplies around the globe. The ability to control strategic areas of ocean by means of a weapon that is silent and can strike with little or no warning has as much impact and meaning on global events today as it did then.

Submarines are not considered vessels per se - the are considered a weapon in and of itself, and the submarine is fought as a weapon during battles.

During WWI, the submarine was used primarily as a regional weapon with restrictions on their use. Its development and significance as a major threat during the war cemented the submarine firmly in the minds of Naval strategists as a major weapon, and submarine technology and experimentation continued to evolve after the war ended.

In WWII, both Germany and the United States showed the world the value of the submarine as a weapon that can change the course of global events. For Germany, its initial successes with U-boats in the Battle of the Atlantic nearly isolated and destroyed Britain by cutting off vital supplies and war material. It wasn't until effective Anti-Submarine Warfare (ASW) measures were developed by the Allies that the U-boat threat was nullified.

In the Pacific, though the Japanese scored a major blow at Pearl Harbor, they failed to destroy either the American submarine or carrier fleets. Executing Unrestricted Submarine Warfare against Japanese targets, American submarines were able to eventually choke the supply lines to Japan the way Germany had done to Britain early in the war, but in the Pacific example, the Japanese weren't able to counter the submarine threat. Their successful attacks on Japanese targets allowed the fleet to rebuild after Pearl Harbor within months.

Submarines in WWII were also used to rescue downed fliers, insert covert operatives into hostile areas, and rescue prisoners and VIP's from enemy areas. These operations continue today.

It should be noted that until the advent of Nuclear Power and significant increases in battery technology, submarines up to that point weren't true submersibles. They were built primarily as surface ships with limited submerged operational capability. Nuclear Power changed that forever. With unlimited power, a modern submarine is only restricted by the needs of her crew. With more power comes more speed and the ability to add more weapons and operational capability. The submarine during the Cold War evolved into 2 distinct types - Fast-Attack, for ASW operations, and Ballistic Missile, for Strategic Deterrence.

After the START II Treaty removed Ballistic missiles from older type FBM submarines, they were refitted as SEAL delivery vehicles or Cruise missle platforms (SSGN). Fast-Attack submarines are already equipped with both torpedo tube launched and in some cases vertical tube launched (VLS) cruise missiles as well as guided torpedoes.

An FBM's mission is to continually remain undetected - they are the most effective nuclear deterrent that the U.S. has. Fast-Attack submarine missions are multi-faceted, serving as cruise missile platforms, advance scouts for Carrier Battle Groups, hunter-killer missions, SEAL delivery, research missions, and even salvage/DSRV (Deep Submergence Rescue Vehicle) transport and delivery to target.

Today's modern submarines are true submersibles in every sense of the word. The ability to travel undetected in the vast oceans of the world is not only a major advantage, but a distinct physical and psychological threat to any enemy. A single submarine can tie up enemy ASW forces at length, or force them to alter battle plans. The best example is the Falklands War, in which 2 Argentinian Diesel-Electric boats tied up British ASW forces, while their own Fast-Attack, HMS Conqueror, scored the only modern day submarine torpedo kill against the light cruiser General Belgrano. After the war, it was found that the Argentinian submarines never left port.

The last successful wartime sinking of a large Naval vessel was in 1982 by the British Royal Navy attack submarine HMS Conqueror during the Falklands War. The Conqueror attacked and sank the Argentine Cruiser ARA General Belgrano, an old WWII U.S. Navy Light Cruiser sold to Argentina. Although it carried modern homing torpedoes, their reliability was in question, so the Captain of the Conquerorused 1925 era Mk 8 torpedoes instead. The Belgrano sunk within minutes of being struck by 3 torpedo hits, with the loss of over 300 crew.