The Japanese called them "Devil Boats" or "Green Dragons". The Germans called them "Schnellboots". Americans called them "The Mosquito Fleet" or "The Hooligan Navy". But Patrol Torpedo boats, popularly known as "PT boats" or more accurately Motor Torpedo Boats (MTB) were small, fast, and highly maneuverable small craft used by the United States Navy in World War II.

Initially hampered at the beginning of the war by ineffective torpedoes, limited armament, and their comparatively fragile construction, they performed admirably in the Pacific, Atlantic and the Mediterranean theaters of war and their daring tactics earned a durable place in the public imagination that remains strong into the 21st century. They are the precursor of the Navy's fast attack craft used today.
PT boats were primarily designed for high-speed torpedo attacks against much larger ships but would also fulfill a variety of vital roles. PT boats were also used to lay mines and smoke screens, search and rescue operations for downed aviators, and carried out intelligence and raider operations.

However, following the Allies gaining air superiority during the daylight hours in various theaters, Japanese supply missions in the Pacific and German and Italian supply missions in the Mediterranean gradually shifted to ones that made use of barges in shallow waters. PT boats were more often deployed against barges rather than warships, which explained why most boats were retrofitted with machine guns and cannons. PT boats were the perfect weapons to counter barge traffic.
PT's were in more frequent contact with the enemy, and at closer range, than any other type of surface craft. PT officers and enlisted men garnered two Medals of Honor, 22 Navy Crosses, 3 Distinguished Service Crosses, a Distinguished Service Medal, and numerous Silver Stars.

On December 7, 1941, there were only 29 PT's in the fleet but by December 7, 1943, there were more than 29 squadrons Forty-three PT squadrons, each with 12 boats were formed during World War II by the U.S. Navy. PT boat duty was extremely dangerous, and the squadrons suffered an extremely high loss rate in the war.
Of the 531 PT Boats in service during the war, a total of 99 were lost, or roughly 18.6%, with 32 lost to accidents or friendly fire, 27 were scuttled to prevent capture, 8 were rammed, 2 were destroyed by Kamikazes, 9 were destroyed by naval mines, 6 were sunk by enemy coastal artillery, 8 were strafed and 7 sunk by enemy naval gunfire.

Since the end of WW II, and even before, PT Boats have become part of the popular culture and national imagination.
In 1945, with the war still going on, John Ford, a captain in the US Naval Reserve, directed the film "They Were Expendable" starring Robert Montgomery, himself a Navy veteran of D-Day, and John Wayne, loosely based on PT-41 and other PT boats in the Philippines following Wake Island.

The 1963 film "PT-109" starred Cliff Robertson as Lt. (jg) John F. Kennedy, a semi-biographical account of the then-president's war service in the Solomon Islands during WW II. In 1959, when a high school student asked Kennedy how he had become a war hero, he answered "It was easy - they sank my boat."
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As President John F. Kennedy, who as a scrawny 25-year-old lieutenant had commanded the ill-fated PT-109 in the Solomon Islands in 1943 would later state: "PT boats were an embodiment of John Paul Jones' words: "I wish to have no connection with any ship that does not sail fast, for I intend to go in harm's way" and often expressed the opinion that PT boats were the 20th Century equivalent of the cavalry.