Compared to the ships of today that can go over 25 knots. Most submarines today are nuclear powered, but some are still diesel powered because they're still good in shallow waters. The U.S., Russia, France, and England have nuclear submarines. The Navy's fleet of Trident submarines is the largest and most powerful submarine force in the free world, and provides the nation's first line of strategic deterrence. Attack submarines, like the new USS Seawolf , weigh about 9,000 tons, and are about 353 feet long.
Attack submarines carry torpedoes to fire against enemy ships and submarines.
They are also armed with tomahawk cruise missiles. Ballistic missile submarines, like the USS Ohio , weigh about 19,000 tons and are about 560 feet long. They can launch 24 Trident ballistic missiles against enemy land targets thousands of miles away. Modern nuclear submarines are extremely quiet, especially at slow speeds, and are difficult to detect with passive sonar. The effectiveness of active sonar, which is relatively short range, can be reduced through coating a submarine's hull with material that absorbs active acoustic energy.