The Royal Navy has taken delivery of a new naval sonar system five months ahead of schedule. The Sonar 2087 is a defense capability needed by the Royal Navy in order to detect a new generation of increasingly stealthy submarines which often operate close to shore - making them very hard to detect. Ordered in 2001, the system was due to enter service in May 2006. The Sonar operates at a lower frequency (longer wavelength) to enable the detection of a hostile submarine at longer range - enabling the ship's captain to take action before the enemy submarine gets within torpedo range.
(Source: publictechnlogy.net)