Undersea Warfare

Undersea warfare falls into two main categories, anti-submarine operations and mine warfare. Anti-submarine operations are complex, demanding and time consuming, requiring close coordination of many assets and a very high level of understanding of environmental conditions. The P3C Orion aircraft are among the most effective assets Surface combatants are important elements in creating a layered defence of mission essential units in searching for adversary submarines, whether by means of their radar and infrared systems, or by monitoring the sonobuoys they drop into the sea to detect submarine generated noise. Some sonobuoys can also be used actively, generating a sound signal to echo range on an underwater target. The primary weapon of maritime patrol aircraft will be lightweight torpedoes specially designed for use against submarine targets.

Carefully positioned submarines also have considerable ability to detect adversary submarines by listening for their noise on towed sonar arrays. Similar devices are being fitted to a number of the RAN's surface combatants, which also have active hull mounted sonar and carry light weight torpedoes. These systems are primarily intended for self-defence, but may be employed to cover and protect other units when the frigates or destroyers are escorting high value or mission essential units such as amphibious forces. In these circumstances, layered defence will probably be the most effective way to ensure that such units are successfully protected. Seahawk helicopters possess a variety of sensors and are also able to deploy sonobuoys and drop light weight torpedoes. They will generally be used by the frigates and destroyers to investigate and engage an underwater contact while the surface ships remain out of torpedo range. Both Sea Sprite and Sea King helicopters can be used as lightweight torpedo carriers. Defensive minefields are a very useful tool to complicate the task of adversary submarines because they can have a considerable deterrent effect, as well as reducing the areas that require to be searched.

Mines can be cheap and simple enough to be employed by the smallest powers or terrorist groups and represent a formidable challenge for maritime powers. Mine warfare has considerable potential for gaining and maintaining the initiative against an adversary. Preemptive sowing of even a limited number of mines outside its bases or in choke points can prevent its ships from deploying or returning to port and will force it to conduct time consuming and painstaking mine countermeasures (MCM). Mine warfare is subject to some restrictions under international law, nevertheless, it has been employed covertly on at least one occasion as a form of maritime terrorism by a nation-state.

Mine countermeasures are most effective when forces possess a high degree of understanding of the environment, preferably in the form of route and local bottom surveys which can minimise the time taken to detect and identify mines. MCM operations will be limited to the minimum area required to be made safe to allow operations to resume or shipping movements to continue and they will be conducted so as to achieve the greatest possible threat reduction in the shortest possible time.