The PT boat was very different from the first generation of torpedo boat, which had been developed at the end of the 19th century and featured a displacement hull form. These first generation torpedo boats rode low in the water, displaced up to 300 tons, and had a top speed of . During World War I Italy, the US and UK developed the first high-performance petrol-powered motor torpedo boats (often with top speeds over ) and corresponding torpedo tactics, but these projects were all quickly disbanded after the Armistice. World War II PT boats continued to exploit some of the advances in planing hull design borrowed from offshore powerboat racing and by using multiple lightweight but more powerful marinized aircraft-derived V-12 engines were able to grow in both size and speed.