An advantage to large naval ships is the ability to house large and powerful weapons, from missiles to cannons. The Navy has been working on an advanced type of weapon called a railgun. Unlike most guns which rely on a chemical fuel (such as gunpowder), railguns use electricity to create powerful magnetic fields. With the proper setup, these fields can accelerate objects to incredible velocities; in this case the projectiles can reach 4500 mph to 5600 mph.
Much of the research and development had been done by the Office of Naval Research in their own laboratories, but soon they will be testing the first industry railgun prototype launcher built by BAE systems. This device uses 32 megajoules of energy, while Navy’s device was only firing at 1.5 Mj. (A one ton car travelling at 100 mph is roughly one megajoule.) At first the testers are aiming for a range of just 50-100 nautical miles (57-115 miles) but intend on expanding this to 220 nautical miles (253 miles) in the future.
More work will have to be done before these weapons will be found on ships though, as automated reloading and cooling systems have to be developed. The Office of Naval Research though has recently award $10 million contracts to Raytheon Corp, BAE Systems and General Atomics to create pulsed power systems that should allow a for a firing rate of 6-10 shots per minute.