Title: History of submarines
Content:  During the American Civil War, the Union was the first to field a submarine. The French-designed Alligator was the first U.S. Navy sub and the first to feature compressed air (for air supply) and an air filtration system. It was the first submarine to carry a diver lock, which allowed a diver to plant electrically detonated mines on enemy ships. Initially hand-powered by oars, it was converted after 6 months to a screw propeller powered by a hand crank. With a crew of 20, it was larger than Confederate submarines. Alligator was 47 ft long and about 4 ft in diameter. It was lost in a storm off Cape Hatteras on 1 April 1863 while uncrewed and under tow to its first combat deployment at Charleston. The Intelligent Whale was built 
Title: H. L. Hunley (submarine)
Content:  H. L. Hunley, often referred to as Hunley,  CSS H. L. Hunley, or as CSS Hunley, was a submarine of the Confederate States of America that played a small part in the American Civil War. Hunley demonstrated the advantages and the dangers of undersea warfare. She was the first combat submarine to sink a warship (USS Housatonic (1861)), although Hunley was not completely submerged and, following her successful attack, was lost along with her crew before she could return to base. The Confederacy lost 21 crewmen in three sinkings of Hunley during her short career. She was named for her inventor, Horace Lawson Hunley, shortly after she was taken into government 
Title: History of submarines
Content:  three managed to escape. During the American Civil War both sides made use of submarines. Examples were the Alligator, for the Union, and the Hunley, for the Confederacy. The Hunley was the first submarine to successfully attack and sink an opposing warship. (see below) In 1863 the Sub Marine Explorer was built by the German American engineer Julius H. Kroehl, and featured a pressurized work chamber for the crew to exit and enter underwater. This pre-figured modern diving arrangements such as the lock-out dive chamber, though the problems of decompression sickness were not well understood at the time. After its public maiden dive in 1866, the Sub Marine Explorer 
Title: Submarine warfare
Content:  The age of submarine warfare began during the American Civil War. The 1860s was a time of many turning points in terms of how naval warfare was fought. Many new types of warships were being developed for use in the United States and Confederate States Navies. Submarine watercraft were among the newly created vessels. The first sinking of an enemy ship by a submarine occurred on 17 February 1864, when the Confederate submarine, a privateer, sank the sloop USS Housatonic (1861) in Charleston Harbor, South Carolina. Shortly afterward, however, H. L. Hunley sank, with the loss of her entire crew of eight.
Title: Submarine
Content:   In 1800, France built a human-powered submarine designed by American Robert Fulton,. The French eventually gave up on the experiment in 1804, as did the British when they later considered Fulton's submarine design. In 1864, late in the American Civil War, the Confederate navy's became the first military submarine to sink an enemy vessel, the Union sloop-of-war USS Housatonic (1861). In the aftermath of its successful attack against the ship, using a gun-powder-filled keg on a spar as a torpedo charge, H. L. Hunley also sank, because the shock waves from the explosion killed the crew instantly and prevented them 
Title: Submarines in the United States Navy
Content:  The first submarine used in combat was the USS Turtle, the Turtle was built in 1775 and was made to attach explosive charges to the hulls of the ships. Several attempts were made against British Ships in American harbors in 1776, but none were successful. Other submersible projects date to the 19th century. Alligator was a US Navy submarine that was never commissioned. She was being towed to South Carolina to be used in taking Charleston, but was lost in bad weather on 2 April 1863 off Cape Hatteras, North Carolina. On February 17, 1864, the H. L. Hunley (submarine) became the first submarine to sink a warship. Real progress began late in the century with the building of the USS Holland (SS-1), named after John Philip Holland. The boat was developed at Lewis Nixon's Crescent Shipyard located in Elizabeth, New Jersey. This pioneering craft was in service for 10 years and was a developmental and trials vessel for many systems on other early submarines.
Title: Turtle (submersible)
Content:  the first years of the nineteenth century and took it to Europe when the United States proved largely uninterested in the design. During the American Civil War, the Confederate States of America, faced with a similar situation to that of the colonies during the War of Independence, developed an operational submarine CSS H.L. Hunley, whose destruction of the USS Housatonic in Charleston Harbor in February 1864 was the first successful submarine attack in history. By the early-twentieth century, the world's navies were beginning to adopt submarines in larger numbers. Like Bushnell's design, these boats mimicked the natural forms of marine animals in their 
Title: French weapons in the American Civil War
Content:  During the American Civil War, the Union-built and French-designed submarine Alligator was the first U.S. Navy submarine and the first to feature compressed air (for air supply) and an air filtration system. Initially hand-powered by oars, it was converted after 6 months to a screw propeller powered by a hand crank. With a crew of 20, it was larger than Confederate submarines. Alligator was 47 feet (14.3 m) long and about 4 feet (1.2 m) in diameter. The submarine was lost in a storm off Cape Hatteras on April 1, 1863 with no crew and under tow to its first combat deployment at Charleston.
Title: USS Alligator (1862)
Content:  USS Alligator, the fourth United States Navy ship of that name, is the first known U.S. Navy submarine, and was active during the American Civil War (the first American submarine was during the Revolutionary War, and was operated by the Continental Army, vice Navy, in 1776 against British vessels in New York harbor). During the Civil War the Confederate States Navy would also build their own submarine,.
Title: History of submarines
Content:  Oliver Halstead and tested by the U.S. Navy after the American Civil War and caused the deaths of 39 men during trials. The Confederate States of America fielded several human-powered submarines, including CSS H. L. Hunley (named for its designer and chief financier, Horace Lawson Hunley). The first Confederate submarine was the 30 ft Pioneer, which sank a target schooner using a towed mine during tests on Lake Pontchartrain, but it was not used in combat. It was scuttled after New Orleans was captured and in 1868 was sold for scrap. The similar Bayou St. John submarine is preserved in the Louisiana State Museum. CSS Hunley was intended for attacking Union ships that were blockading Confederate seaports. The submarine had a long pole with an explosive charge in the bow, 

Question: who invented the submarine during the civil war?
Answer: Horace Lawson Hunley.