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P.T. Boats were powered by three 4M-2500 Packard Marine Engines developed by
the Packard Motor Car Company specifically for the United States Motor Torpedo
Boat program. The Packard Marine is a powerful high-speed supercharged, lightweight
engine of the aviation type. Basic characteristics
- 60 degree Vee-type twelve-cylinder
- Liquid cooled
- 4 stroke
cycle
- Fuel - 100 octane aviation gasoline
Horse
power - 1200 hp - 1940
- 1350 hp - 1943
- 1500 hp -
1945
Increases in horsepower were made to compensate for the
constant additions of heavier armament put on the boats during WWII. P.T. Boats
achieved 45 knots top speed during shakedown testing but averaged about 40 knots
under normal combat conditions. The forces of nature had profound effects
on the PT boat's speed. Warm sea temperatures would hinder the engine's cooling
systems and sea growth on the bottom of the boats would also reduce speed performance.
The height of sea swells would not only affect speed but could damage the boat
and possibly injure the crew if a PT Boat tried to run head-on into a 12-foot
sea at high speeds. |