Naval Blockade

"What are they going to do, fly over us with magic powers?"

"Everywhere wood can swim, I find this flag of England."

— Napoléon Bonaparte

A naval blockade is a tactic and/or strategy that prevents the movement of goods, supplies, and forces by sea. The greater the volume of traffic to be prevented, the greater the blockade—and the greater the resources needed to maintain it.

A close blockade is probably what most people think of, a fleet within weapons-range and probably the direct sight of the enemy. This works better for a visual medium. A loose or distant blockade is beyond the defenders' weapons-range and probably beyond their direct sight as well. A distant blockade will take place on the open sea, such as the one imposed by the Royal Navy in the English Channel and North Sea in both World Wars. A close blockade is often more effective, taking advantage of narrow inlets, but often entails more clashes with the enemy and operating further from one's supply and repair bases. How these would work in space depends on the author.

Under current rules of warfare, a blockade is an act of war. The dispatch of a trade-interdiction/blockade fleet is often an ultimatum to either agree to certain terms or declare war.

There are always those foolhardy enough to try Running the Blockade.

May overlap with Gunboat Diplomacy. Contrast Hold the Line, for when the good guys are trying to keep their enemies from overrunning their position, and Easy Logistics, which this is used to counter.

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Examples:

Anime & Manga

• Gunka No Baltzar: Holbeck deploys one on the Norden-Trade Duchy after it is invaded which leads to a war.
• In Arpeggio of Blue Steel, humanity's naval and seafaring capabilities are torn to shreds after engaging in a losing battle with the "Fleet of Fog", AI ships with directives to attack any human ships attempting to venture out to sea. Fortunately, one of the captured Fog ships, I-401 "Iona", only remembers one set of orders: "To obey Gunzou Chihaya", giving humanity a chance to defeat the Fog ships.

Comic Books

• Wonder Woman (1987): During Greg Rucka's run the US Navy circled Themyscira with ships ostensibly to offer aid after Hera destroyed it's magical protections and ties with sub dimensions, knocking it into the sea not far from the US's eastern seaboard. However the ships remained around the island much longer, taking unofficial control of access to Themyscira and even if the US government refused to admit they'd created a blockade they also refused to remove it without the Amazons handing over certain pieces of their tech which the Amazons refused to do due to the ease with which said pieces could be used to design new forms of WMDs.

Fan Works

• The Citadel Council tries this in Origins, a Mass Effect/Star Wars/Borderlands/Halo Massive Multiplayer Crossover against the Terminus Systems (the source of an Alien Invasion), but it doesn't work. Also kind of inverted when the Council pulls the opposite of the trope, blocking everything in to try to keep an area safe as the war expands. Still doesn't work though.
• This Bites!: The World Government blockades Sabaody with naval and privateer ships in an attempt to stop any of the Supernovas (but especially the Straw Hats) from managing to get to Fishman Island and from there to the New World. Cross organizes a Dead End Race for the Supernovas and the other pirate crews on Skelter Bite at the time as a way to fight their way through the blockade, with the Thousand Sunny's Goan Cannon delivering the final punch needed.
• The Mountain and the Wolf:
  • On returning to Dragonstone from the failed parley with Cersei, Tyrion and the rest of the courtiers learn the Iron Fleet is blockading the mouth of Blackwater Bay, having left before they did. Tyrion thinks they'll have to fight their way through, but the Wolf instead drops them off on the beach of Driftmark, telling them that he'll go to one of the ships and either kill the Ironborn or prove they can be safely let through. Later he returns, the ship have seen a fierce battle, telling them he "negotiated" with Euron Greyjoy to abandon Cersei and go claim the Salt Throne from his niece.
    This is in fact entirely BS, as the reader knows: Euron has been the Wolf's captive since the battle of Dragonstone and replaced by an impostor, the Wolf [[spoiler:teleported to the Iron Islands to ritually murder Euron there and returned, and the Iron Fleet now obeys his commands.
  • During the siege of King's Landing, Davos is able to sail up the Blackwater with no resistance as the chain blocking it was still lowered, allowing his forces to join the battle and take the city much faster. It turns out Euron or rather Akkarulf masquerading as Euron butchered the winch guards and stuffed their bodies into the gears to prevent the chain from being raised.
  • Later, the Iron Fleet returns to Dragonstone, surrounding the island and bringing down almost every raven they send to request help from Daenerys. The Wolf participates in planning for the defense of King's Landing against them, including a complicated move where Davos orders his ships to feint a retreat so as to attack the Ironborn from behind while they're in range of the wall defenses. It's all moot when Daenerys returns and the Iron Fleet disappears northwards (it was another ploy on the Wolf's part to ensure that Daenerys' forces would stay in King's Landing instead of spreading out according to their political needs).
• Shadows over Meridian: During the Swamp arc, Phobos' forces learn that Lord Kur has commandeered every ship in the region to seal off the local capital of Everdeen, which is built in the middle of a lake. They deduce that he's doing this in conjunction with strict ration control to starve the nonhuman parts of the population until they lash out in desperation, giving Kur an excuse to purge them.

Films — Live-Action

• Star Wars
  • The Phantom Menace starts with the Trade Federation blockading the planet of Naboo. The reason given is that they hope to resolve some sort of trade dispute this way, as the source of the dispute was Senator Palpatine, and the Federation thought that blockading (and later occupying) his home planet might shut him up. Unfortunately for them, he was pulling the strings on both sides the whole time.
  • In The Empire Strikes Back when the Imperial fleet arrives over Hoth, they form a blockade to prevent Rebel ships from escaping, but they didn't seem to count on them having an ion cannon capable of disabling a Star Destroyer.
• Thirteen Days: John F. Kennedy goes with this instead of an airstrike to deal with ships carrying missiles to Cuba. Since a blockade is technically an act of war, they decide to call it a quarantine.
• It's never seen but a blockade going on somewhere in Central America is constantly referred to in 2010: The Year We Make Contact.
• In Godzilla (2014), the American Navy attempts to block Godzilla's approach to Hawaiis shore. Unfortunately, they didn't anticipate Godzilla swimming under their blockade and displacing so much water that the destroyers and aircraft carriers get tossed about in the waves that proceed to flood the city in a tsunami.
• In Jupiter Ascending, Balem orders a planetary blockade of Earth as soon as he finds out that Jupiter escaped his agents. It fails miserably.
• X-Men: First Class features an alternate universe version of the Cuban Missile Crisis including the blockade.

Literature

• Jerry Pournelle's novel King David's Spaceship. The port city of Jikar was blockaded by patrols of pirate ships. The pirates demanded not only tribute but also the heads of the Masters of each Guild in the city.
• In the Arcia Chronicles, The Church blockades Orgonda from the sea after it refuses to acknowledge Pierre Lumen (whom the clergy endorsed) as king. The blockade is eventually lifted by the Eland Mariners.
• Following the destruction of Theramore in Tides of War the Horde navy forms a ring around Kalimdor, blocking Alliance ships from reaching their allies there.
• Horatio Hornblower series. Hornblower and the Hotspur involves the British blockade of the French port of Brest and Hornblower's deeds during the blockade, while Ship of the Line has him as part of a squadron blockading French-occupied Spain (and losing his ship to stop four French ones from escaping). Since Hornblower is Allergic to Routine, blockade service on his ship tends to be a lot more eventful than on others.
  • Lampshaded in Admiral Hornblower in the West Indies: during Bolivar's revolution in Central America, an extremely daring rebel privateer uses one ship ^note which is, to be sure, a former British ship of war that he bought and converted into his private yacht and a forged proclamation to fool the Spanish into thinking the Royal Navy is blockading the Panamanian coast. Even though the Spanish only ever see that one small ship, the Royal Navy's reputation is such that no one is willing to even try to run the blockade, except a single ship carrying some desperately-needed weapons for the Spanish army.
• In the Aubrey-Maturin series, the British blockade of France during The Napoleonic Wars and North America during the War of 1812 are shown, unusually, from the perspective of the blockaders. As the weather is terrible, the ships spend a long time at sea without any interesting port calls, there's little chance for loot and glory, and the hygiene and comfort of a sailing ship are what we would expect from Wooden Ships and Iron Men, the duty is understandably highly unpopular among both officers and crew.
• Honor Harrington: This was employed by the Royal Manticoran Navy against the Solarian League by blockading wormhole termini in Solarian space.
• In The Wheel of Time, this is the crucial element of the plan to besiege Tar Valon, a city on an island in the middle of a river. Controlling the bridges is relatively easy, but no one has ever managed to block the harbors. In the end, It's managed by using a newly-rediscovered magic to transform the harbor chains into an unbreakable material, rendering them an effective barrier.
• In Debt of Honor the Japanese are fed false information through their mole that the US is going to impose one on the home islands so they'll redeploy their forces. The tactic works and it leaves the real targets open to US carrier strikes.
• In Arctic Rising on is imposed on Thule by a multinational fleet when Gaia launches their terraforming project.
• Charis and the Church do this to each other in the Safehold novels. The Church try to do it through diplomacy, by outlawing trade with Charis. It didn't work too well - because too many ports were economically dependent on the Charis trade, this tended to be evaded through Loophole Abuse or outright ignored, and the one time the Church tried to enforce the decree at swordpoint, Charis responded by returning to the port in question with a regiment of Marines and burning everything within two miles of the waterfront to the ground. Charis, on the other hand, simply had their Navy and privateers capture or sink any ship flagged to an enemy nation that they could find. Since Charis' navy outnumbered every other navy in the world combined by a significant margin, and were more powerful on a ship-by-ship basis as well, this worked.
• Military thriller Victoria features one as part of its near-future Second Civil War story. After the Confederation states declare their independence, the US government institutes a blockade against them to prevent them from obtaining war supplies from overseas. However, they still manage to get some weapons, for example across the Canadian border.
• The Hunt for Red October has the US government fearing that the Soviet fleet is doing this when, if anything, it's an inversion of this: They're not trying to keep US ships in, but trying to keep one particular ship out. Not that this makes the government feel any better about a multitude of Russian ships within spitting distance of the US coast.
• Gotrek & Felix: "Orcslayer" has Gotrek and Felix arrive at a coastal dwarf hold on a trade ship to find it blockaded by orc ships. They manage to pierce through, but the hero's welcome quickly dies when it turns out the hold is also besieged by land and the trader only had spices instead of food or useful supplies.
• The Lost Voices novel The Twice Lost has an unusual example. Hundreds of mermaids in the San Francisco Bay, working together with their enchanted voices, raise a wall of water hundreds of feet tall that touches the bottom of the Golden Gate Bridge. This forces the government agents to stop shooting at them - if enough of them die, the tsunami will swamp San Francisco. The plan is not only to stop the killing of mermaids, but also to attract media attention and force the government to negotiate with them. As news spreads, other tribes of mermaids also renounce the murder of humans and form their own blockades in different harbors.

Live-Action TV

• Babylon 5:
  • In the episode "And Now For A Word" a Centauri battlecruiser shows up and positions itself between the station and the jumpgate, threatening to fire on any ships attempting to travel between them, unless Centauri ships that had been impounded by Babylon 5 are released.
  • The first episode of the third season had a planet the Rangers were using as a training base being surrounded by Centauri blockade mines. Sheridan and Delenn had to mount a rescue mission that got complicated when a Shadow vessel showed up.
  • Late in the fourth season, Earth Force ships have a blockade going around the colony of Proxima III. One ship participating in it ruthlessly destroys two passenger liners attmpting to escape, killing over ten thousand civilians, and provoking Sheridan into going on the offensive.
• In House of the Dragon, Lord Corlys Velaryon, who possesses the biggest fleet in Westeros, fought against the Triarchy in the Stepstones islands to prevent them from eventually blockading King's Landing. After defeating them once and for all, he sides with Rhaenyra Targaryen for her claim to the Iron Throne and tells her he can now use his fleet to blockade King's Landing, as it is now the seat of Rhaenyra's enemies.
• In Star Trek: Deep Space Nine the Klingons mined the "entire" Bajoran system to prevent Dominion ships from entering the Alpha Quadrant. However because of 2-D Space they only mined a circle around the system rather than the entire system, which would have taken centuries to do anyway.
  • A more simple example occurs later, when Sisko mines the entrance to the wormhole to prevent Dominion reinforcements.
• During the Klingon civil war on Star Trek: The Next Generation the Federation put a blockade along the Klingon-Romulan border to keep the Romulans from supplying the Duras Sisters.
• The Germans, with help from the Finns, do this to harass the Soviet Navy in Soviet Storm: World War II in the East. The only time the blockade is truly lifted is when the Finns finally decide to capitulate with the Soviets in 1944.

Theater

• In the first scene of 1776 John Adams includes blockading the colonies' ports in his list of British atrocities while trying to spur Congress to action.

Video Games

• You can do this in some of the Civilization games. It prevents the blockaded city from working water tiles or gaining income from trade routes. This applies also in Sid Meier's Alpha Centauri.
• Knights of the Old Republic: The first part of the game takes place on the planet Taris, after the player, Carth and Bastila crash land there. To keep Bastila from escaping, the Sith blockade the planet while they conduct a search for her. Eventually Malak gets impatient and decides to destroy it all from orbit.
• Star Wars: The Old Republic: During the war with the Sith, the Mandalorians blockaded a major hyperspace route known as the Hydian Way. Their purpose was to draw the Jedi out into battle, which they eventually did, and got their tails handed to them by the Mandalorians. Eventually, a fleet of smugglers attacked the blockade and the Republic quickly took advantage of the situation were finally able to break the blockade.
• At one point in Pokémon Ruby and Sapphire, Team Magma/Aqua use a team of tamed Wailmer to blockade one of the port cities, forcing you to deal with them and advance the story before you explore the ocean.
• World of Warcraft:
  • In the Howling Fjord, the Northsea Freebooter pirates set up a blockade around the Alliance settlement of Westguard Keep. A daily quest involves breaking it by dropping bombs from a zeppelin.
  • Gadgetzan, on the coast of Tanaris, is being blockaded by Southsea pirates. One quest has the player fly over the blockade in a rocket-propelled hot air balloon and drop bombs on the pirate ships.
  • The Garrison Shipyard allows players to send ships off on naval missions, including Blockade missions which must be completed to unlock areas of the map. Repeatedly.
• One of the Empire of the Rising Sun's moves in Command & Conquer: Red Alert 3 was to use one of its massive floating fortresses to stop all naval activity in the North Sea. The Allies and Soviets were forced to call a truce until it was dealt with. Another blockaded the Strait of Gibraltar.
• In Dishonored, the Empress briefly mentions such a blockade being deployed around Dunwall.
• In the Halo backstory, the UNSC blockaded the 26 Draconis System in an effort to keep FTL drive components from being shipped out, leading to an incident that sparked the Insurrection.
• Cerberus does this a couple of times in Mass Effect 3, once at the Grissom Academy with a cruiser and a force of fighters, and another around Omega with a force of larger ships after usurping Aria T'Loak.
• A common tactic in the Total War series, though it depends on the era. In Rome, all harbors have trade routes and ships attacking the harbor blockade it. In Empire, ships can attack trade routes themselves, gaining plunder, while ships that enter empty ports belonging to the enemy deprive them from building any new ships.
• A mechanic in Master of Orion 2 allows hostile fleets^note Even fleets consisting of a single ship to blockade a star system. This drastically decreases economic activity in that system and cuts it off from its owner. For colonies reliant on imported food, this can result in starvation.
• This is one of the high-level abilities in Age of Empires III where you can block off a player's regular shipments from their home city. Of course by the time you have that ability it isn't really needed, but still.
• One of the German levels in Empire Earth has cargoes spawn regularly and head for German ports, your task is to have enough planes and submarines to ensure they get past the Royal Navy (and sending a sub to the English coast so a spy can insert conflicting orders into their supply system).
• Warframe: Saturn was historically a merchant world, but by the time of the game the Grineer have blockaded the famous shipping lanes and driven everyone else out.

Web Original

• In Dino Attack RPG, the entire planet Earth has been placed under quarantine by the Galactic Council to prevent the spreading of the Maelstrom's forces to other planets, and the quarantine is enforced by a fleet of Space Police ships blockading the planet. Unlike most examples, other ships are allowed to travel to Earth despite the blockade, but the Space Police are enforcing the rule that nothing is allowed to leave the planet until the threat of the Maelstrom has been dealt with.

Western Animation

• In the Avatar: The Last Airbender episode "Avatar Roku" the Gaang has to get to a temple inside the Fire Nation, the border of which is blockaded by the Fire Navy.
  • Note the blockade as depicted is a bit unrealistic, even for a close blockade; two lines of ships steaming in opposite directions passing close abroad is overkill, risks collisions, and a waste of fuel and time. Realistically all that's required for an effective close blockade is for the various ships involved to have overlapping weapons ranges, so that nothing can penetrate without coming under fire. Based on their attempts to shoot down the Gaang riding on Appa, their max effective range is a few miles and they could easily maintain the blockade with about a third of the ships we see.
• Appears also in The Legend of Korra, where the Northern Water Tribe blockades the ports of the Southern Water Tribe, ostensibly to "protect" the spirit portal Korra opened up at the South Pole.
• Star Wars: The Clone Wars: This was a common tactic for the Separatists, both for cutting Republic supply lines and pressuring systems into joining them or staying out of their way.
• Star Wars Rebels: In the episode "Wings of the Master", the Empire has established a blockade around the planet Ibaar, whose people are being starved into submission. The Rebels attempt to break through the blockade in order to deliver supplies to the starving people, but they fail in their first attempt and take heavy losses before finally retreating. Their second attempt fares much better when the Rebels manage to get their hands on a new prototype B-wing class starfighter colloquially known as a "Blockade Buster". With the help of the B-wing and its main cannon, the Rebels are able to smash the blockade by destroying one of the Imperial light cruisers, opening a gap for the Ghost to break through and deliver the supplies to the planet's surface.

Real Life

• During the American Revolutionary War, the British forces under Cornwallis were holed up in the city of Yorktown. When a French fleet blockaded Yorktown and prevented the Royal Navy from re-supplying the British forces, the troops were forced to surrender when the Continental Army struck.
• The late 18th and early 19th centuries saw France and Britain try to inflict these on each other at various times in their mutual rivalry for European supremacy. Britain being an island was both its main strategic strength (all the superiority of one's army was pointless if it couldn't cross water safely) and strategic weakness (Britain's economy was dependent on shipments from overseas), depending on how well the Royal Navy could do its job.
  • Their continual intercepting of merchant ships from third-party countries carrying goods destined for or coming from each others' countries resulted in two wars with the United States, the Quasi-War in 1798 against France and the War of 1812 against Britain. The War of 1812 also included a British blockade of American ports, which basically shut down trade among the US states, and which devastated the country's (unusually trade-centric on account of its good access to the sea) economy since their merchant ships could no longer take to the sea (to the point where the heavily-trade-dependent New England states discussed making a separate peace with Britain, with some radicals even debating secession from the US entirely). The US Navy was too weak to try to lift it, hence the lack of important naval battles during a three-year war involving two trade-oriented countries. The few times that American light-warships did manage to sneak past the blockade they were able to cause disproportionate damage to British merchant shipping, with the USS Essex being probably the most successful example and the USS Constitution being the most iconic.
  • Done by the British towards Norway during The Napoleonic Wars. The blockade was not entirely safe, and Norwegian boats made quite a few runs. Some of them also resorted to capering.
  • Napoleon tried to put this on the British with the Continental System, which was designed to starve Britain of the trade and resources needed for its burgeoning Industrial Revolution. While Britain did see a significant drop in exports, the Continent suffered at least as much; numerous smugglers evaded the ban (which Napoleonic France's land-based customs agents had a hard time policing), and some countries openly defied the blockade/embargo and traded with Britain. In particular, Russia continued its trade with the British; this brought about Napoleon's doomed 1812 invasion.
• One of the most effective large-scale blockades ever was during The American Civil War, where this was a key part of the Union's strategy to defeat the Confederacy; the blockade strategy was part of the greater Union strategy that became known as the Anaconda Plan. At full effect, approximately 95% of pre-war traffic in Confederate ports was cut off.
• Britain and Germany did this to each other simultaneously during both World War I and World War II as a way to choke off trade. Britain's surface fleet was unparalleled, so Germany had to resort to submarines in order to try to isolate the British Isles. This was a major problem for Germany, as the only effective way they could use submarines as a blockade was to sink all ships suspected of carrying war material, which inevitably brought international condemnation and dragged neutral nations deeper into the war on the opposing side.
• During World War II, Italy and Britain also blockaded each other in the Mediterranean Sea. Both blockades were ineffective at first: the British re-routed their merchant shipping around the Horn of Africa, while Italian merchant captains quickly figured out that the Royal Navy knew their usual routes. But over time, the larger British navy was able to whittle down the Italian navy and merchant marine, cutting off Axis supply lines into North Africa and giving their own ships relative freedom to operate in the Mediterranean again. The British had better luck blockading Italian East Africa; they controlled both routes out of the Mediterranean, and Italy had no meaningful fleet (merchant or military) south of the Suez Canal.
• Toward the end of the Pacific War, the US blockaded Japan, dropping mines in their ports and vital routes and sinking cargo ships with submarines, which severely disrupted logistics and transport. It is said that had the campaign started earlier, the war would have ended much sooner.
• The Blockade of Wonsan in the Korean War, the successful denial of a strategic port to the North Korean navy which allowed UN forces (mainly the US) to supply troops and materiel from Japan to the Peninsula relatively hassle-free.
• The US Navy implemented one during Cuban Missile Crisis, though it was termed a quarantine and limited to missile parts for political reasons like the fact that a blockade is legally an act of war. It was a compromise action between doing nothing (the missiles did little to upset the military balance but would have been catastrophic for American diplomacy) and something more drastic like sudden air strikes or a full scale invasion of the island (a much more aggressive action which would have destabilized the situation much more than the Crisis did historically).
• In the first months of the Russian invasion of Ukraine in 2022, Turkey closed off access to the Black Sea so no Russian military ship would enter it. The Russian Black Sea fleet itself, after occupying most of Ukraine's coasts save for the South-Western one with Odesa, started blockading Odesa. Agreements were reached, with Turkey's mediation, in order to let grain shipments from Odesa cross the Black Sea and ensure grain supplies to many countries, though that hasn't stopped Russians from attacking Odesa's port facilities with ballistic missiles. The fleet has since reduced its blockade attempts due to the increased capacity of navy-less Ukrainians to strike them from land (such as Western-delivered Harpoon missiles).

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