Sonar

Sonar, known in early British service as ASDIC, enabled the Royal Navy to detect submarines beneath the surface. This capability was critical during both world wars, especially in the Battle of the Atlantic, where German U-boats threatened vital supply routes. By emitting sound waves and analysing their echoes, sonar operators could determine the position and movement of submerged targets.

The development of sonar changed anti-submarine tactics. Escort vessels could locate submarines and coordinate attacks using depth charges and later weapons such as the Squid mortar. Improvements in sonar technology increased detection range and accuracy, while training and doctrine evolved to make best use of these systems. Sonar remains a fundamental component of naval warfare, particularly in submarine operations and maritime surveillance.