Naval warfare in the context of Commerce raiders

The Battle of Actium was a naval battle fought between Octavian's maritime fleet, led by Marcus Agrippa, and the combined fleets of both Mark Antony and Cleopatra. The battle took place on 2 September 31 BC in the Ionian Sea, near the former Roman colony of Actium, Greece, and was the climax of over a decade of rivalry between Octavian and Mark Antony.

In early 31 BC, the year of the battle, Antony and Cleopatra were temporarily stationed in Greece. Mark Antony possessed 500 ships and 70,000 infantry and made his camp at Actium, while Octavian, with 400 ships and 80,000 infantry, arrived from the north and occupied Patrae and Corinth, where, with the help of Marcus Vipsanius Agrippa, he managed to cut Antony's southward communications with Egypt via the Peloponnese. Octavian had previously gained a preliminary victory in Greece, where his navy successfully ferried troops across the Adriatic Sea under the command of Agrippa. Octavian landed on mainland Greece, opposite the island of Corcyra (modern Corfu), and proceeded south on land.

The United States Navy (USN) is the maritime service branch of the United States Armed Forces and the naval warfare force of the United States. It is the world's most powerful navy with the largest displacement, at 4.5 million tons in 2021. It has the world's largest aircraft carrier fleet, with eleven in service, one undergoing trials, two new carriers under construction, and six other carriers planned as of 2024. With 336,978 personnel on active duty and 101,583 in the Ready Reserve, the U.S. Navy is the third largest of the United States military service branches in terms of personnel. It has 299 deployable combat vessels and about 4,012 operational aircraft as of 18 July 2023. The U.S. Navy is a part of the United States Department of Defense and is one of six armed forces of the United States and one of eight uniformed services of the United States.

The United States Navy traces its origins to the Continental Navy, which was established during the American Revolutionary War and was effectively disbanded as a separate entity shortly thereafter. After suffering significant loss of goods and personnel at the hands of the Barbary pirates from Algiers, the United States Congress passed the Naval Act of 1794 for the construction of six heavy frigates, the first ships of the Navy. The United States Navy played a major role in the American Civil War by blockading the Confederacy and seizing control of its rivers. It played the central role in the World War II defeat of Imperial Japan. The United States Navy emerged from World War II as the most powerful navy in the world, succeeding the British Navy. The modern United States Navy maintains a sizable global presence, deploying in strength in such areas as the Western Pacific, the Mediterranean, and the Indian Ocean. It is a blue-water navy with the ability to project force onto the littoral regions of the world, engage in forward deployments during peacetime and rapidly respond to regional crises, making it a frequent actor in American foreign and military policy.

The Battle of Lepanto was a naval engagement that took place on 7 October 1571 when a fleet of the Holy League, a coalition of Catholic states arranged by Pope Pius V and led by the navies of the Republic of Venice and the Spanish Empire, inflicted a major defeat on the fleet of the Ottoman Empire in the Gulf of Patras. The Ottoman forces were sailing westward from their naval station in Lepanto (the Venetian name of ancient Naupactus – Greek Ναύπακτος, Turkish İnebahtı) when they met the fleet of the Holy League which was sailing east from Messina, Sicily.

Lepanto marks the last major engagement in the Western world to be fought almost entirely between rowing vessels, namely the galleys and galleasses, which were the direct descendants of ancient trireme warships. The battle was in essence an "infantry battle on floating platforms". It was the largest naval battle in Western history since classical antiquity, involving more than 450 warships. Over the following decades, the increasing importance of the galleon and the line of battle tactic would displace the galley as the major warship of its era, marking the beginning of the "Age of Sail".

The Republic of Singapore Navy (RSN) is the maritime service branch of the Singapore Armed Forces (SAF) responsible for defending the country against any seaborne threats and as a guarantor of its sea lines of communications. The RSN traces its origins to the Royal Navy when Singapore was still a crown colony of the British Empire. The service was formally established in 1967, two years after its independence from Malaysia in 1965, and had undergone a substantial modernisation ever since – which has led them into becoming the most powerful navy in Southeast Asia.

The RSN also regularly conducts operations with the navies of its neighbouring countries to combat piracy and terrorist threats in the congested littoral waters of the Strait of Malacca and Singapore. It also jointly operates the Fokker 50 maritime patrol aircraft with its counterparts from the Republic of Singapore Air Force (RSAF) to provide air surveillance of the seaward approaches to Singapore, which is one of the busiest sealanes in the world. The RSN has engaged in international anti-piracy operations further abroad, partaking in the multinational Combined Task Force 151 off the Gulf of Aden.

A navy, naval force, military maritime fleet, war navy, or maritime force is the branch of a state's armed forces principally designated for naval and amphibious warfare; namely, lake-borne, riverine, littoral, or ocean-borne combat operations and related functions. It includes anything conducted by surface ships, amphibious ships, submarines, and seaborne aviation, as well as ancillary support, communications, training, and other fields.

The strategic offensive role of a navy is projection of force into areas beyond a country's shores (for example, to protect sea-lanes, deter or confront piracy, ferry troops, or attack other navies, ports, or shore installations). The strategic defensive purpose of a navy is to frustrate seaborne projection-of-force by enemies. The strategic task of a navy also may incorporate nuclear deterrence by use of submarine-launched ballistic missiles. Naval operations can be broadly divided between riverine and littoral applications (brown-water navy), open-ocean applications (blue-water navy), and something in between (green-water navy), although these distinctions are more about strategic scope than tactical or operational division.

Marines (or naval infantry) are military personnel generally trained to operate on both land and sea, with a particular focus on amphibious warfare. Historically, the main tasks undertaken by marines have included raiding ashore (often in support of naval objectives) and the boarding of vessels during ship-to-ship combat or capture of prize ships. Marines also assisted in maintaining security, discipline, and order aboard ships (reflecting the historically pressed-nature of the rest of the ship's company and the risk of mutiny). While maintaining many of their historical roles, in modern times, marines also engage in duties including rapid-response operations, humanitarian aid, disaster relief, special operations roles, and counter-terrorism operations. In most nations, marines are an integral part of that state's navy, such as the United Kingdom's Royal Marines or Russia's Naval Infantry; in some countries their marine forces can instead be part of the land army, such as the French Troupes de marine, or, more uncommonly, a nation’s marine forces may be an independent military branch such as the United States Marine Corps or the Ukrainian Marine Corps.

The exact term "marine" is not found in many languages other than English. In French-speaking countries, two terms which could be translated as "marine", but do not translate exactly: troupes de marine (marine troops) and fusiliers-marins (marine riflemen) and fuzileiros navais in Portuguese (lit. 'Naval fusiliers'). The word marine means "navy" in many European languages such as Dutch, French, German, Italian and Norwegian. “Naval infantry” may also refer to sailors forming both temporary and permanent infantry units, such as the British WWI-era 63rd (Royal Naval) Division (an infantry division made-up of Royal Navy sailors and Royal Marines on a semi-permanent basis) or the Imperial Japanese Naval Landing Forces (ad-hoc formations of Imperial Japanese Navy sailors temporarily pressed into service as infantry).

The Royal Navy (RN) is the naval warfare force of the United Kingdom, responsible for defending the UK, the Crown Dependencies, and the Overseas Territories from naval attack or invasion. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against France. The modern Royal Navy traces its origins to the English Navy of the early 16th century; the oldest of the UK's armed services, it is consequently known as the Senior Service.

From the early 18th century until the Second World War, it was the world's most powerful navy. The Royal Navy played a key part in establishing and defending the British Empire, and four Imperial fortress colonies and a string of imperial bases and coaling stations secured the Royal Navy's ability to assert naval superiority. Following World War I, it was significantly reduced in size. During the Cold War, the Royal Navy transformed into a primarily anti-submarine force, hunting for Soviet submarines and mostly active in the GIUK gap. Following the collapse of the Soviet Union, its focus returned to expeditionary operations.

Prize money refers in particular to naval prize money, usually arising in naval warfare, but also in other circumstances. It was a monetary reward paid in accordance with the prize law of a belligerent state to the crew of a ship belonging to the state, either a warship of its navy or a privateer vessel commissioned by the state. Prize money was most frequently awarded for the capture of enemy ships or of cargoes belonging to an enemy in time of war, either arrested in port at the outbreak of war or captured during the war in international waters or other waters not the territorial waters of a neutral state. Goods carried in neutral ships that are classed as contraband, being shipped to enemy-controlled territory and liable to be useful to it for making war, were also liable to be taken as prizes, but non-contraband goods belonging to neutrals were not. Claims for the award of prize money were usually heard in a prize court, which had to adjudicate the claim and condemn the prize before any distribution of cash or goods could be made to the captors.

Other cases in which prize money has been awarded include prize money for the capture of pirate ships, slave ships after the abolition of the slave trade and ships trading in breach of the Navigation Acts, none of which required a state of war to exist. Similar monetary awards include military salvage, the recapture of ships captured by an enemy before an enemy prize court has declared them to be valid prizes (after such ships have been condemned, they are treated as enemy ships), and payments termed gun money, head money or bounty, distributed to men serving in a state warship that captured or destroyed an armed enemy ship. The amount payable depended at first on the number of guns the enemy carried, but later on the complement of the defeated ship.

Commerce raiding is a form of naval warfare used to destroy or disrupt logistics of the enemy on the open sea by attacking its merchant shipping, rather than engaging its combatants or enforcing a blockade against them. Privateering is a form of commerce raiding conducted by independent operators.

Piracy in the Persian Gulf describes the naval warfare that was prevalent until the 19th century and occurred between seafaring Arabs in Eastern Arabia and the British Empire in the Persian Gulf. It was perceived as one of the primary threats to global maritime trade routes, particularly those with significance to British India and Iraq. Many of the most notable historical instances of these raids were conducted by the Al Qasimi tribe. This led to the British mounting the Persian Gulf campaign of 1809, a major maritime action launched by the Royal Navy to bombard Ras Al Khaimah, Lingeh and other Al Qasimi ports. Some critics of the historical narrative, such as Sharjah ruler Sultan bin Muhammad Al Qasimi in his book The Myth of Piracy in the Gulf, argue that the allegations of piracy were exaggerated by the East India Company to cut off untaxed trade routes between the Middle East and India.

Piratical activities were common in the Persian Gulf from the late 18th century to the mid-19th century, particularly in the area known as the Pirate Coast which spanned from modern-day Qatar to Oman. Piracy was alleviated from 1820 with the signing of the General Maritime Treaty, cemented in 1853 by the Perpetual Maritime Truce, after which the Pirate Coast began to be known by the British as the Trucial Coast (present-day United Arab Emirates).

Marine propulsion is the mechanism or system used to generate thrust to move a watercraft through water. While paddles and sails are still used on some smaller boats, most modern ships are propelled by mechanical systems consisting of an electric motor or internal combustion engine driving a propeller, or less frequently, in pump-jets, an impeller. Marine engineering is the discipline concerned with the engineering design process of marine propulsion systems.

Human-powered paddles and oars, and later, sails were the first forms of marine propulsion. Rowed galleys, some equipped with sail, played an important early role in early human seafaring and warfare. The first advanced mechanical means of marine propulsion was the marine steam engine, introduced in the early 19th century. During the 20th century it was replaced by two-stroke or four-stroke diesel engines, outboard motors, and gas turbine engines on faster ships. Marine nuclear reactors, which appeared in the 1950s, produce steam to propel warships and icebreakers; commercial application, attempted late that decade, failed to catch on. Electric motors using battery packs have been used for propulsion on submarines and electric boats and have been proposed for energy-efficient propulsion.

A harpoon is a long, spear-like projectile used in fishing, whaling, sealing, and other hunting to shoot, kill, and capture large fish or marine mammals such as seals, sea cows, and whales. It impales the target and secures it with barb or toggling claws, allowing the fishermen or hunters to use an attached rope or chain to pull and retrieve the animal. A harpoon can also be used as a ranged weapon against other watercraft in naval warfare.

Certain harpoons are made with different builds to perform better with the type of target. For example, the Inuit have short, fixed-foreshaft harpoons for hunting at breathing holes, while loose-shafted ones are made for throwing and remaining attached to the game.

A ship is a large watercraft designed for travel across the surface of a body of water, carrying cargo or passengers, or in support of specialized tasks such as warfare, oceanography and fishing. Ships are generally distinguished from boats, based on size, shape, load capacity and purpose. Ships have supported exploration, trade, warfare, migration, colonization, and science. Ship transport is responsible for the largest portion of world commerce.

The word ship has meant, depending on era and context, either simply a large vessel or specifically a full-rigged ship with three or more masts, each of which is square rigged.

An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a full-length flight deck and hangar facilities for supporting, arming, deploying and recovering shipborne aircraft. Typically it is the capital ship of a fleet (known as a carrier battle group), as it allows a naval force to project seaborne air power far from homeland without depending on local airfields for staging aircraft operations. Since their inception in the early 20th century, aircraft carriers have evolved from wooden vessels used to deploy individual tethered reconnaissance balloons, to nuclear-powered supercarriers that carry dozens of fighters, strike aircraft, military helicopters, AEW&Cs and other types of aircraft such as UCAVs. While heavier fixed-wing aircraft such as airlifters, gunships and bombers have been launched from aircraft carriers, these aircraft do not often land on a carrier due to flight deck limitations.

The aircraft carrier, along with its onboard aircraft and defensive ancillary weapons, is the largest weapon system ever created. By their tactical prowess, mobility, autonomy and the variety of operational means, aircraft carriers are often the centerpiece of modern naval warfare, and have significant diplomatic influence in deterrence, command of the sea and air supremacy. Since the Second World War, the aircraft carrier has replaced the battleship in the role of flagship of a fleet, and largely transformed naval battles from gunfire to beyond-visual-range air strikes. In addition to tactical aptitudes, it has great strategic advantages in that, by sailing in international waters, it does not need to interfere with any territorial sovereignty and thus does not risk diplomatic complications or conflict escalation due to trespassing, and obviates the need for land use authorizations from third-party countries, reduces the times and transit logistics of aircraft and therefore significantly increases the time of availability on the combat zone.

A false flag operation is an act committed with the intent of disguising the actual source of responsibility and pinning blame on another party. The term "false flag" originated in the 16th century as an expression meaning an intentional misrepresentation of someone's allegiance. The term was originally used to describe a ruse in naval warfare whereby a vessel flew the flag of a neutral or enemy country to hide its true identity. The tactic was initially used by pirates and privateers to deceive other ships into allowing them to move closer before attacking them. It later was deemed an acceptable practice during naval warfare according to international maritime laws, provided the attacking vessel displayed its true flag before commencing an attack.

The term today extends to include countries that organize attacks on themselves and make the attacks appear to be by enemy nations or terrorists, thus giving the nation that was supposedly attacked a pretext for domestic repression or foreign military aggression (as well as to engender sympathy). Similarly deceptive activities carried out during peacetime by individuals or nongovernmental organizations have been called false-flag operations, but the more common legal term is a "frameup", "stitch up", or "setup".

The Regency of Algiers was an early modern semi-independent Ottoman province and nominal vassal state on the Barbary Coast of North Africa from 1516 to 1830. Founded by the privateer brothers Aruj and Hayreddin Reis (also known as the Barbarossa brothers), the Regency succeeded the Kingdom of Tlemcen as a formidable base that waged maritime holy war (Jihad) on European Christian powers. It was ruled by elected regents under a stratocracy led by Janissaries and corsairs. Despite its pirate reputation in Europe, Algiers maintained long-standing diplomatic ties with European states and was a recognized Mediterranean power.

The Regency emerged in the 16th-century Ottoman–Habsburg wars. As self-proclaimed ghazis gaining popular support and legitimacy from the religious leaders at the expense of hostile local emirs, the Barbarossa brothers and their successors carved a unique corsair state that drew revenue and political power from its naval warfare against Habsburg Spain. In the 17th century, when the wars between Spain and the Ottoman Empire, Kingdom of France, Kingdom of England and Dutch Republic ended, Barbary corsairs started capturing merchant ships and their crews and goods from these states. When the Ottomans could not prevent these attacks, European powers negotiated directly with Algiers and also took military action against it. This policy would emancipate Algiers from the Ottomans.

The Soviet Navy (Russian: Военно-морской флот (ВМФ) СССР, romanized: Voyenno-morskoy flot (VMF) SSSR) was the naval warfare uniform service branch of the Soviet Armed Forces. Often referred to as the Red Fleet, the Soviet Navy made up a large part of the Soviet Union's strategic planning in the event of a conflict with the opposing superpower, the United States, during the Cold War (1945–1991). The Soviet Navy played a large role during the Cold War, either confronting the North Atlantic Treaty Organization in western Europe or power projection to maintain its sphere of influence in eastern Europe.

The Soviet Navy was divided into four major fleets: the Northern, Pacific, Black Sea, and Baltic Fleets, in addition to the Leningrad Naval Base, which was commanded separately. It also had a smaller force, the Caspian Flotilla, which operated in the Caspian Sea and was followed by a larger fleet, the 5th Squadron, in the Mediterranean Sea. The Soviet Navy included Naval Aviation, Naval Infantry, and the Coastal Artillery.

A galley is a type of ship optimised for propulsion by oars. Galleys were historically used for warfare, trade, and piracy mostly in the seas surrounding Europe. It developed in the Mediterranean world during antiquity and continued to exist in various forms until the early 19th century. It typically had a long, slender hull, shallow draft, and often a low freeboard. Most types of galleys also had sails that could be used in favourable winds, but they relied primarily on oars to move independently of winds and currents or in battle. The term "galley" originated from a Greek term for a small type of galley and came in use in English from about 1300. It has occasionally been used for unrelated vessels with similar military functions as galley but which were not Mediterranean in origin, such as medieval Scandinavian longships, 16th-century Acehnese ghalis and 18th-century North American gunboats.

Galleys were the primary warships used by the ancient Mediterranean naval powers, including the Phoenicians, Greeks and Romans. The galley remained the dominant type of vessel used for war and piracy in the Mediterranean Sea until the start of the early modern period. A final revival of galley warfare occurred during the 18th century in the Baltic Sea during the wars between Russia, Sweden, and Denmark. In the Mediterranean, they remained in use until the very end of the 18th century, and survived in part because of their prestige and association with chivalry and land warfare. In war, galleys were used in landing raids, as troop transports and were very effective in amphibious warfare. While they usually served in wars or for defense against piracy, galleys also served as trade vessels for high-priority or expensive goods up to the end of the Middle Ages. Its oars guaranteed that it could make progress where a sailing ship would have been becalmed, and its large crew could defend it against attacks from pirates and raiders. This also made it one of the safest and most reliable forms of passenger transport, especially for Christian pilgrims during the High and Late Middle Ages.