Given a text passage, come up with an appropriate title for it. The title should accurately represent what the main focus of the passage is. The title of a passage may be present in the first few sentences of the passage and/or be referred to multiple times in the passage. The title should be 1-5 words long.
Q: A PT boat ( short for Patrol Torpedo boat ) was a torpedo - armed fast attack craft used by the United States Navy in World War II . It was small , fast , and inexpensive to build , valued for its maneuverability and speed but hampered at the beginning of the war by ineffective torpedoes , limited armament , and comparatively fragile construction that limited some of the variants to coastal waters .
A:
PT boat