In war, logistics is everything. Armies march on their stomachs, tanks and planes need fuel, and weapons need ammunition. Though there are various ways of getting these things to the front lines, if the fighting is taking place near a major port, chances are supplies will be brought in by ship.
The enemy knows this, and to prevent those supplies from reaching their destination, a common tactic is to send a fleet of ships to surround said port and interdict any traffic in or out, thus depriving the enemy forces of the supplies they need to keep up the fight. To be more effective, this may coincide with an offensive from the other side, trapping the enemy forces between an advancing front and the blockade.
Depending on the setting, this can be done to port towns or cities, a nation's coastline, if you have a fleet large enough, or, in sci-fi works, an entire planet. Obviously, the larger the area you're trying to block off, the more ships and other resources you're going to need. Thus, the effectiveness of a blockade often depends on the terrain. The smaller an opening to a sea, the easier it will be to concentrate ships and cut off trade routes.
Blockades are generally differentiated by how close they are to their objective. A close blockade is probably what most people think of, a line of ships close together, well within sight of their target. This is also the one that works best for a visual medium. A loose blockade positions itself just over the horizon, with the idea that enemy ships can be drawn out into an ambush. A distant blockade will take place on the open sea, such as Germany's U-Boat wolf packs being used to try and cut the supply lines between the U.S. and Britain during both World Wars. Each has their own advantages and disadvantages, like a close blockade being most effective, but requiring more resources and having no place close for ships to go if they need repairs. How these would work in space
depends on the author.
Despite the force of ships surrounding their destination, there are those foolhardy enough to try and get through anyway. This is known as 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.
Anime & Manga
- Gunka No Balzer: 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.
- 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.
- Jerry Pournelle's CoDominium 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.
- 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.
- 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 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.
- 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.
- 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.
- 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.
- 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.
- One of the Empire of the Rising Sun's moves in 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 fleetsnote 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.
- 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.
- 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.
- 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 came to be known as the Anaconda Plan. At full effect, approximately 95% of pre-war traffic in Confederate ports was cut off.
- As noted above, was also employed to deal with Soviet ships bearing missiles to Cuba during the Cuban Missile Crisis. It was a compromise action between doing nothing (the missles did little to upset the military balance but would have been catastrophic for American diplomacy) and something more drastic like sudden air strikes (a much more aggressive action which would have destabilized the situation much more than the Crisis did historically).
- 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.
- Britain and Germany did this to each other simultaneously during both World War One 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.
- Also during World War II, Italy and Britain blockaded each other in the Mediterranean Sea. Between Italy being very close to the blockaded North Africa and having extremely Genre Savvy merchant captains (who noticed very quickly that the Royal Navy could somehow find out their pre-programmed routes and tended to stay away from them) and British naval superiority (and having another way to resupply Egypt through the Red Sea. In fact, Italy's goal was to slow down the resupplying by denying the shorter route through the Mediterranean Sea), both blockades were mostly ineffective on the short run, but in the end their inability to replace the ships sunk by the Royal Navy meant that in the end Italy ran out of ships with which to run the blockade.
- A more effective one was the one placed by the Royal Navy on the Italian East Africa, as Italy had no meaningful fleet (merchant or military) south of the Suez Canal while Britain could use both the ships of the East India Station and those of the Mediterranean Fleet based in Alexandria.
- 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 burgeniong Industrial Revolution. While Britain did see a significant drop in exports, the problem was that many countries on the Continent not called France suffered significantly as well - smugglers all around evaded the ban (which Napoleonic France's land-based customs agents had a hard time policing) and several openly defied the call and traded with Britain, most notably Russia (which spurred Napoleon's doomed invasion).
- French and British attempts at intercepting merchant ships 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, incidentally, also included a British blockade of American ports, which did much to hamper operations of the US Navy, hence the relative lack of naval battles during a several years-long war. The few times that American warships did manage to get out to sea, they were able to cause considerable damage by attacking 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.
- The Blockade of Wonsan in the Korean War, the successful denial of a strategic port to the North Korean navy.