Britain has introduced a new submarine detection system, Sonar 2087, that, in addition to being more effective, is less annoying to aquatic non-combatants (the fish). The new sonar does this by relying more on passive (just listening) detection, and broadcasting on frequencies that do not annoy the fish and whales. Of course, any new noise broadcast into the ocean will annoy the sea creatures there, but some noises are more of a problem than others. The new sonar is a towed array, that is let loose from the rear of the ship. Sonar 2087 remains connected via a cable, and is lowered to the optimum depth for listening or broadcasting (like radar.) The new towed array can be used at higher ship speeds, and can be deployed, and recovered, in rougher seas (up to Sea State 6). Also included are the most modern electronics and software. Britain is installing the new sonar on six of its Type 23 frigates. These 4,900 ton warships are the backbone of the Royal Navys anti-submarine forces.