Starting about 1500, clever but complicated firing mechanisms were invented to generate sparks to ignite the powder instead of a lit match, starting with the wheel lock, snaplock, snaphance, and finally the flintlock mechanism, which was simple and reliable, becoming standard with the musket by the early 17th century. At the beginning of the 16th century, the first European fire ships were used. Ships were filled with flammable materials, set on fire, and sent to enemy lines. This tactic was successfully used by Francis Drake to scatter the Spanish Armada at the Battle of Gravelines, and would later be used by the Chinese, Russians, Greeks, and several other countries in naval battles. Naval mines were invented in the 17th century, though they were not used in great numbers until the American Civil War. They were used heavily in the First and Second World Wars. Air-deployed naval mines were used to mine the North Vietnamese port of Haiphong during the Vietnam War. The Iraqi Navy of Saddam Hussein used naval mines extensively during the Tanker War, as part of the Iran–Iraq War. The first navigable submarine was built in 1624 by Cornelius Drebbel, it could cruise at a depth of 15 feet (5 m). However, the first military submarine was constructed in 1885 by Isaac Peral. The Turtle was developed by David Bushnell during the American Revolution. Robert Fulton then improved the submarine design by creating the Nautilus. The Howitzer, a type of field artillery, was developed in the 17th century to fire high trajectory explosive shells at targets that could not be reached by flat trajectory projectiles. Organizational changes resulting in better training and intercommunication, made the concept combined arms possible, allowing the use of infantry, cavalry, and artillery in a coordinated way. Bayonets also became of wide usage to infantry soldiers. Bayonet is named after Bayonne, France where it was first manufactured in the 16th century. It is used often in infantry charges to fight in hand-to-hand combat. General Jean Martinet introduced the bayonet to the French army. They were used heavily in the American Civil War, and continued to be used in modern wars like the Invasion of Iraq. Balloons were first used in warfare at the end of the 18th century. It was first introduced in Paris of 1783; the first balloon traveled over 5 miles (8 km). Previously military scouts could only see from high points