They are used for scientific research as well as warfare.
Smaller submarines were used for scientific research (underwater animals, plants, etc.)
During WW2, all the major countries involved used submarines.
Introduced undersea warfare. They were used by the Germans to destroy British ships.
Warships traveled with Merchant ships for protection.
Submarine warfare is a military tactic used by many nations where submarines are used to attack enemy ships or as a direct deterrent. This was used extensively by the Germans during World War II.
Submarine warfare has existed since the early 1900's, and continues to this day. Though the last ship sinking by a submarine was in the Falklands War, the evolving missions of submarines have taken submarine warfare well beyond just sinking ships and submarines.
Nuclear power is used to generate electricity.
There were subs in the 19th century, but they were really a part of naval warfare from World War One to the end of the Cold War. If large scale war breaks out in the near future, expect submarines to be a huge factor on the ocean front.
Depends on what class of Submarine you are talking about. Balistic Submarines are a nuclear deturent that assures retaliation in the event of a country using nuclear weapons against one another. Attack Submarines have grown a lot since WWII. They are now capable of conducting Anti-Surface Warfare, Anti-Submarine Warfare, Land Attack Strikes, Harbor Mining, Speacial Forces Insurcian & Extraction, & Intelligance Gathering. Scientific Research Submarines are used for Biological Research, Search and Recovery of Shipwrecks.
Submarine - A ship designed to travel underwater used for exploration and warfare. Submarine - A sandwich that is shaped like the submarine ship, also known as a grinder or hoagie.
Before the war, people mainly used ships and boats, therefore, the people with the submarine could destroy these ships.
Guerre de Course, merchant warfare.
Commerce warfare (Guerre de Course).