Command of the sea

With command of the sea, a country (or alliance) can ensure that its own military and merchant ships can move around at will, while its rivals are forced either to stay in port or to try to evade it.

The British Royal Navy held command of the sea for most of the period between the 18th to the early 20th centuries, allowing Britain and its allies to trade and to move troops and supplies easily in wartime, while its enemies could not.

For example, Venice claimed the Adriatic Sea, and exacted a heavy toll from vessels navigating its northern waters.

During World War II, aircraft also became an effective countermeasure to command of the sea, since ships could not defend themselves well against air attack.

[citation needed] The entire Japanese naval strategy during World War II in the Pacific was to acquire command of the sea by largescale destruction of Allied naval power, until their fleet was either destroyed or rendered irrelevant by the Battle of Leyte Gulf giving command of the sea to the Allies.

In modern warfare blue-water navy implies self-contained force protection from sub-surface, surface and airborne threats and a sustainable logistic reach, allowing a persistent presence at range.

During the Falklands War, the British lacked long-range Airborne Warning and Control System (AWACS), which led to ship losses and major damage to others, when the Argentinian attack aircraft came into the view of ship radar at approximately the same time they would fire antiship missiles, and only a short time before they made bombing attacks.

Given the importance of naval aviation, the term may be considered to be strongly linked to the maintenance of aircraft carriers capable of operating in the oceans.

"[citation needed] While a blue-water navy can project sea control power into another nation's littoral, it remains susceptible to threats from less capable forces.

Sustainment and logistics at range yield high costs and there may be a saturation advantage over a deployed force through the use of land-based air or surface-to-surface missile assets (whether on terrain-following or ballistic trajectories), diesel-electric submarines, or asymmetric tactics such as Fast Inshore Attack Craft.