Naval vessels are large, complex systems. Filled with mounds of electronic systems, a frigate or corvette reacts sensitively toward electromagnetic waves. Propeller and sailing noises should not reveal an approaching naval vessel in any way. This also applies to the infrared signature, which is nothing more than cutting-edge high-tech camouflage. The infrared radiation has to be minimized to as low a level as possible to ensure that a naval vessel is not discovered.