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Silent Running Mode

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"But only whiffs of paraffin
Or creamy rings that fizz and fade
Show where the one-eyed Death has been
That is the custom of 'The Trade'."
The Trade by Rudyard Kipling

Sometimes the only way to survive against the enemy's ships is to be stealthy. In this situation, the ship and crew tries to be as quiet as possible, knowing that the slightest sound and/or energy reading could be picked up by the enemy's sensors and draw their fire. This often involves deactivating all non-essential systems on the ship for a while.

This trope is almost invariably featured in a Sub Story. This trope has also been Recycled In Space, and many a Cool Starship has been called upon to do submarine-style silent running. Often this depends on the unrealistic conviction that there is sound in space, but it could be denoted as minimizing heat discharge or something similar to prevent detection by sensors. Not to be confused with the film Silent Running.

Radio Silence is often one of several requirements.


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    Anime & Manga 
  • Captain Harlock: Arcadia of My Youth features an episode running largely on Sub Story tropes. Captain Harlock's starship has to hide from the Illumidas on a planet covered by a corrosive ocean. The Arcadia is strong enough to resist immersion, but the enemy ships aren't (two of them explode after trying). The acid is also scrambling all method of detection except for sonar; hence the crew has to stay silent to avoid being located or be attacked by depth charges from the remaining enemy ship.

    Comic Books 
  • One of the few contemporary Commando stories "The Silent Strike", has a combined SBS and SAS team adopting gas-electric hybrid snowmobiles; using the petrol engine for the approach, and the electric engine for a surprise attack when the target is expecting them to be infiltrating slowly on foot.

    Film — Live-Action 
  • In Batman Begins, the Batmobile has a stealth mode, which involves cutting to an all-electric engine and turning off all exterior lights, and instead navigating by some kind of sensor system. Despite being right in the middle of several cop cars on a two-lane highway, somehow nobody notices the gigantic all-terrain military vehicle slipping between them. To be fair, it was night and most of the streetlights were out, but still ...
  • Blue Thunder had this as one of the features of the eponymous helicopter.
  • Das Boot, with the portrayal of true silent running in undersea warfare.
  • During a face-off with a Russian submarine in Crimson Tide, the USS Alabama — running silent — attempts to float its communications buoy and retrieve the rest of a disrupted message. The buoy rises slowly and silently as both crews wait for the other to make a move, and then the spool binds up, sending a very audible screech through the water.
  • Down Periscope both plays this straight and subverts this trope at different points in the movie, including the time that an all-hands singalong to "Louie Louie" is a vital part of their disguise. This might be a reference to the The Hunt for Red October example below.
  • In The Enemy Below a German sub is playing a cat and mouse game with an American cruiser. At one point the hiding underwater is getting to the Germans and one goes nuts. The Captain puts on music and gets all of his men to sing, which can be heard by the cruiser on their hydrophones. The Americans think they've gone nuts, but the American captain sees what is happening.
  • In the movie version of The Hunt for Red October, they switch on the silent propulsion system and the crew starts singing the Soviet National Anthem. One of the crew worries that they'll be heard. Ramius says to let them sing.
    Jonesy: [on the USS Dallas] The Russian disappeared. One minute he was steady 4000 yards off the bow and... then he was gone. And for a second, I thought I heard...
    Capt. Mancuso: Heard... what?
    Jonesy: I thought I heard singing, sir.
    Mancuso: Singing?
    Jonesy: ...Yes, sir.
    • Later in the movie, the Dallas successfully locates the Red October despite her silent propulsion and is tailing her in her baffles (i.e. directly behind, a sonar blind spot) when she pulls a sharp turn called a "Crazy Ivan" to see if anything's behind her. Mancuso immediately orders "All stop, quick quiet!"
  • Hunter Killer: When USS Arkansas is traveling through Polyarny's underwater defense grid, Andropov silently signals for quiet, at which point captain Glass states "Set condition; 'Ultra-quiet'" over the sub's intercom, silencing everything save a rattling bolt in the torpedo room, which is swiftly dealt with by the crew.
  • Invention for Destruction: While attempting to sneak through the undersea tunnel into the Volcano Lair, the reconnaissance sub encounters the pirate submarine coming the other way. The commander orders the helmsman to cut all engines and allow the sub to sink to the bottom.
  • Done twice in Master and Commander. First, Captain Aubrey has his men tow a crippled HMS Surprise into the fog to avoid further bombardment by the French frigate, Acheron. Then later when Acheron sneaks up on the Surprise again, Captain Aubrey uses a decoy to distract his opponents and keeps the lights of the stern at the Surprise well doused, all the while running a course east in order to bring the ship on Acheron's tail the very next morning.
  • The Matrix, when the Nebuchadnezzar has a close call with the sentinels.
  • Done in Run Silent, Run Deep by both the crew of the USS Nerva and, later, by the Japanese submarine that was hunting them. This sets up a suspenseful sequence in which both the Nerva and the Japanese sub go quiet and even cut their engines, eventually drifting just past each other underwater.
  • Star Trek:
    • The Wrath of Khan uses the nebula as a variant. Its radiation scrambles the sensors of both ships.
    • Also The Undiscovered Country which has a Klingon Bird of Prey that can fire while cloaked — Uhura even says, "If she's here, she's rigged for silent running."
  • Star Wars:
  • Wing Commander: Numerous examples, ranging from individual fighters to an entire fleet of ships, using the "energy and heat signatures" version of the trope. For best effect, they typically attempted to conceal themselves in the clutter of an asteroid or debris field, or in the case of the fleet, by putting themselves in low orbit over a planet. At one point, the heroes' Battle Star is attempting to lay low inside of an asteroid's crater, while the Kilrathi methodically drop warheads into each crater trying to find the one the Terrans are sheltering in. One particularly infamous moment as the crew sitting silently on the bridge, warned that them speaking or making any noise could be picked up... through the Kilrathi ships.

  • Referenced in The Areas of My Expertise in a table of short words and abbreviations used by submariners to conserve oxygen. It contains the term "SR" for Silent Running mode. It claims that the term comes from the movie Silent Running, because it is the sub-mariners' favorite movie.
  • In Ark Royal, the titular ship engages in this tactic occasionally with mixed success. The first time, it helps that the fleet also uses drones to mimic the signatures of carriers to fool the enemy. However, the alien stealth systems are much more effective, although humans quickly figure out how to, at least, approximate their location by certain weak emissions.
  • In Deliverance Lost, the Avenger sneaks out of the Isstvan system by shutting down almost every system, leaving the crew cold and dark for days. It's not explicitly stated how it helps escape detection, but a reasonable assumption is that the ship is minimizing its electromagnetic signature.
  • One of the common concepts of the tactics used in the Honor Harrington books is that the spaceships used in the battles are virtually invisible when the "wedges" that normally propel them are powered down, and the rare obedience to physics means that a powered-down ship is not motionless and can coast on a ballistic course with virtually no chance of detection. They're almost incapable of maneuvering, though. Honor uses this trick, along with a ridiculous amount of luck, to get the drop on a Havenite fleet guarding the Cerberus system, from which she and a few hundred thousand POWs and Peep political prisoners are attempting to escape.
    • Specifically, a ship without its wedge powered is invisible to gravitic sensors; it continues to emit everything else (heat, EM, etc) as normal and still presents a perfect target for radar and laser systems. However, lots of commanders in the Honorverse don't bother with anything but the gravitics, since gravitics operate at FTL speeds as opposed to light-speed EM-based methods, and it's assumed that any ship attempting aggressive action will have to have its wedge running. Basically, Honor's entire plan hinged on the Peeps being terminally lazy and failing to check their EM sensors. In a later novel, she and Michelle Henke hung a giant pair of fuzzy dice on the tactic for the benefit of a gaggle of hero-worshiping midshipmen, dissecting all of the myriad ways the Peeps could have spotted Honor coming light minutes away and turned her entire fleet into space junk with a single salvo. To quote Henke below:
      Michelle Henke: All things considered, Her Grace's plan may not have been the single rashest, most foolhardy, do-or-die, all-or-nothing throw of the dice in the history of the Royal Manticoran—or Grayson—Navy. If it wasn't, however, I have so far failed to find the plan that was.
    • Later, the Mesan Alignment develops ships that use a new type of propulsion that is completely invisible to gravitic sensors, the so-called Spider drive (it uses incredibly powerful Tractor Beams to pull itself towards the hyperspace wall (which is everywhere). These new types of ships are, essentially, this 'verse's equivalent of submarines: slow and fragile (no impeller wedges or sidewalls), but hidden and capable of dealing great destruction without advance warning. The Mesans also make sure the ship is as invisible to non-gravitic sensors as possible.
  • The Lensman series features at least one ship with a Silent Running Mode. Ships can detect each other at a distance by picking up stray emissions from the atomic power plants which supply their energy, but unscreenable noise from their own power plants limits the range of detection to a value which is roughly the same regardless of ship type. A special ship is built in which the atomic plant can be shut down completely for short periods, with enough power to run essential systems provided by a diesel-powered generator. This simultaneously increases the ship's own detection range by at least an order of magnitude, and renders it immune to long-range detection by other ships (though it can still be picked up by short-range systems such as telescopes and radar).
  • Given that Glen Cook's Passage at Arms is basically a sci-fi retelling of Das Boot, it's not surprising at all that it has this trope up the wazoo. Cook even invents a special spaceship type for this, a so-called "climber", that "climbs" into the higher levels of hyperspace inaccessible to other types of ships. In his typical Shown Their Work fashion he amply lampshades that the main problem for such ships is overheating.
  • During The Ship Who... Searched, while planetside Tia and Alex deliberately cause an avalanche burying Tia under snow to avoid detection. As pirates scan the area, Tia shuts down as many of her systems as she can and Alex has to move as little as possible to avoid making noise.
  • Star Trek:
    • Used interestingly in the novel The Great Starship Race. Kirk orders the Enterprise rigged for silent running as they play cat-and-mouse with a Romulan ship. But he then has Spock emit a subspace radio signal of just one watt. The Romulans focus all their scanners on that one little watt trying to find the ship, only for Spock to then open up the transmitters and hit them with a high-intensity wide-spectrum radio broadcast that overloads and fries the Romulans' sensors.
    • A different novel, Doctors Orders, features the Enterprise (under the command of McCoy) being forced to go into silent running mode to avoid detection by an overpowered Orion ship.
  • The Thrawn Trilogy. Karrde starts out Dark Force Rising hiding on an asteroid, watching the Empire take over Myrkr. He only gets caught because Thrawn knows Karrde is exactly the sort of person to do that—Thrawn specifically tells Captain Pellaeon not to initiate a focused scan of the asteroid, which would have revealed Karrde's ship but would also have tipped Karrde off and let him escape (similar to an active ping on a submarine). Karrde only escapes because his Force-sensitive copilot turned everything back on before Thrawn's Interdictor Cruisers finished generating a gravity well trap.
    • There's a point in Galaxy of Fear where our heroes, on the run from the Empire, set down on an airless rock, power down every system they can spare, and watch a Star Destroyer pass overhead.
  • World War Z. Attempted during a battle between two Chinese submarines. Underwater zombies mess it up.
  • In Stephen Baxter's Xeelee Sequence novel Exultant, when an asteroid base goes into stealth mode, everyone around the base is quiet. One character points out that there's no reason for this, but another responds that it's purely psychological—being quiet helps everyone feel that they're being stealthy.

    Live-Action TV 
  • Airwolf liked to do this all the time. Well, not literally all the time, because then they wouldn't get to draw attention to it, but that switch was flipped fairly often. One episode involved a group of criminals infiltrating a base in a helicopter (a normal one). They did this by shutting off the engine just before getting close, letting the inertia of the spinning rotor land them safely without making much noise. This actually tips Hawke about the identity of the criminals, as this trick was pioneered by him and his brother during The Vietnam War.
  • The only time anyone was able to destroy a Minbari battleship in Babylon 5, Captain Sheridan was hiding his light cruiser in an asteroid field. He then had the nuclear warheads on board modified into mines, while the battleship kept searching for them. The human ship then send out a distress call, which immediately gave away their position and had the Minbari chase right after them, into the mines. (In a blackly amusing twist, both sides think the other's action was dishonourable - the Minbari find being baited into a trap unfair, the humans point out they were only coming so they could finish off the wounded.)
  • Firefly:
    • In the pilot episode, the characters have to do this against the Alliance to keep from getting boarded and searched as they do some illegal salvage — unfortunately for our heroes, their residual heat signature is still detected, so they have to escape by throwing out a decoy.
    • When rescuing the Captain from Niska's space station, Wash has Serenity going unpowered so Niska's men won't see them coming. Given this means no maneuvering, Zoe compares it to throwing a dart from six thousand miles away.
  • A rare version from the Age of Sail. In the Horatio Hornblower TV series, Hornblower manages to sail his tiny cutter into the middle of the Spanish fleet in some fog. He tries to do some damage control by Dressing as the Enemy and being very quiet. They sail under the French colours and wear remnants of French uniforms and clothes as French and Spanish are allies. It almost works. Unfortunately, on one of the Spanish ships, there is an officer who knew that La Reve was captured by the British.
  • Red Dwarf:
    • In one episode, every system aboard Starbug but for the bare minimum needed to survive was switched off in an attempt to hide from a simulant's scanners. Their cover was blown when a robot (who was the robot equivalent to an alcoholic) bumped into a control panel, turning some of the ship's electronics back on.
    • An earlier episode establishes the concept when hiding from simulants, though the AR machine prevents it.
  • Star Trek:
    • The Star Trek: The Original Series episode "Balance of Terror" is a virtual remake of the 1957 film The Enemy Below.
    • The Star Trek: The Next Generation episode "Face of the Enemy" specifies that a Romulan ship's systems have to be perfectly balanced and calibrated in order for its cloaking device to work; this was exploited when a Federation sympathizer created an engine imbalance to "poke a hole" in the cloak and allow Enterprise to detect it.
    • In Star Trek: Deep Space Nine, the show's main Cool Ship, the Defiant, had a cloaking device. Since in the earlier seasons the Big Bad Dominion had weaponry that could easily destroy Federation starships, the Defiant's only real defense upon being approached by a Jem'Hadar ship was to cloak, go to Silent Running Mode and pray they weren't noticed. The Jem'Hadar started scanning with a form of radiation that no Alpha Quadrant spacefaring power used; accordingly, the Romulan officer who was acting as trainer/consultant didn't know if the cloaking device would block it; it didn't. Presumably, the next generation of cloaking devices did. Add in that the cloak added in with the overpowered weapons, shields, and sensors made even "cloaked silent running" a difficulty because of the sheer power the Defiant requires for its size.
  • Mildly invoked in the episode "Justice" from Smallville. While infiltrating a LexCorp complex, Green Arrow turns off his communication feed with Watchtower by saying, "Switching to silent running." Presumably, this is so he can plant explosives throughout the complex without having to listen to potential objections from Chloe.

    Video Games 
  • Elite Dangerous allows starships to enter silent running by closing all their heat radiators. The ship will quickly begin to overheat, requiring that most systems including the life support be shut down to keep heat output low. Low heat levels will significantly reduce your radar signature, though enemies within 300 meters can still pick you up. Smugglers often take the most extreme measures to remain hidden from police when docking, such as flying through the station airlock at max speed with every single system on their ship shut down in order to evade detection.
  • In the Fallout series of games, the Silent Running perk takes the phrase much more literally. You can run silently.
  • From the Depths has detection systems (like radar) for vessels which will massively improve their accuracy at the cost of lighting them up like a Christmas tree to sensors. Passive detection systems exist which can only pick up active sensors but have negligible emissions. Submarines in particular field mostly passive systems; you'll know there's one there, but your cannons won't be able to get a bead on it. Automated Control Blocks can disable and enable sensors on demand, so a fleeing ship can kill its sensors to reduce pursuer accuracy.
  • The Normandy of Mass Effect can briefly use one of these. Stealth in Mass Effect consists of trapping EM radiation in heatsinks, making it invisible to detection systems (but not literally invisible, but space is so huge it's almost impossible to see a ship out a window without being right on top of them). The duration of silent running is limited to how much energy the sinks can store; if they exceed capacity, they will discharge into the ship itself, cooking the crew.
    Joker: Stealth drive engaged. Only way they'll detect us is if you all start singing the Russian national anthem.
    • This becomes a minor plot point in Mass Effect 2. During Legion's loyalty mission, Legion informs Joker to engage the stealth systems of the Normandy SR-2 and approach a Geth space station. Joker brings up the fact that the ship is still visible despite the stealth system and they could look out windows and still see the Normandy. Legion responds that Geth (being a race of sentient AI) do not use windows on their vessels, as they're a structural weakness, relying entirely on detection systems. This gets brought up again in Mass Effect 3 when you use the same tactic:
      Joker: Like the Geth are just sitting there going "those organics would never try the no-windows thing twice!"
    • As explained by Engineer Adams in 3, the rebuilt SR-2 has one major advantage over the SR-1: it can use the stealth drive during faster-than-light travel. This makes it possible to be in stealth mode before entering a system, whereas before the FTL blue-shift would light the enemy sensors off like a flare. In-game this explains how the SR-2 is able to enter enemy territory without getting detected.
  • Possible, but rarely used in the MechWarrior series. Mechs can shut down completely to remove themselves from electronic detection. This won't make you invisible, but a good observation point could let you set up an ambush. Mechwarrior 4 and Living Legends also allows players to flip their Enemy-Detecting Radar from "Active" to "Passive"; passive mechs are very difficult to detect, but lose almost all of their radar range and cannot establish missile locks. The effects of passive radar can be stacked with a friendly Angel ECM bubble in Living Legends, rendering a mech completely invisible to all forms of radar. Living Legends also has Stealth Armor, unique to the "Anubis" Stealth Expert mech, which grants it a tiny radar signature and full-powered standard radar, at the cost of sealing up the mech's coolant ports, making it vulnerable to Over Heating with reckless weapon use.
  • In Outer Wilds, your spaceship does not have this feature, which is a problem, since the anglerfish of Dark Bramble are blind but have very keen hearing, and fully three of them are blocking the route to a story-critical location. The solution then is to simply not engage your ship's thrusters when near the monsters, relying on inertia to let you slowly drift past them, right in front of their gaping jaws. This is exactly as nerve-wracking as it sounds even in normal circumstances, and it makes getting the Golden Ending particularly excruciating, since it's a Timed Mission.
  • Included in the Silent Hunter Series, and frequently necessary for survival.
  • All Stealth Based Missions involve this in Nexus: The Jupiter Incident.
  • Shattered Horizon allows players to switch off the non-essential systems of their suits to avoid giving off light, showing up on radar, or being affected by EMP grenades. However, doing so disables the suit's thrusters, HUD, and audio simulation, so if you're spotted you're pretty much a sitting duck until you can get it switched back on.
  • Starsiege has a more traditional variant. You can, for the most part, 'run silent' through a combination of switching your radar to passive detection and using heat/energy signature dampeners like the thermal diffuser. Using an Invisibility Cloak outright actually made this tactic more effective, not less, because one of the cloak's secondary effects reduces some of your emissions as well. Specific radar types actually encouraged running silent constantly, so as to remain as sneaky and hard to detect as possible. This was generally not necessary in singleplayer, but was incredibly effective in multiplayer.
  • In Subnautica, the Cyclops can be rigged for silent running to avoid detection from predators. Doing so also turns off the exterior floodlights and causes the interior lighting to turn red. The submarine is effectively invisible while Silent Running is active-predators won't notice the sub even if they swim straight into it! The trade-off is the Silent Running mode will drain the Cyclops' power extremely quickly, so it can only realistically be used for a short time.
  • Somewhat roundabout, but manageable in Sunless Sea: Pull back the speed to half-march, and turn off the lights, and it'll be a lot easier to sneak around sea monsters and pirates. The main problem is, going around in complete darkness creeps the hell out of the crew, resulting in Terror climbing particularly fast.

    Western Animation 
  • In the Space Ghost Coast to Coast episode "Flipmode", Space Ghost is putting on a murder mystery dinner set in a submarine. At one point (high on natural gas) he yells, "We're in silent running here. Moltar, we are in silent running! (louder) Do you understand the concept of silent running?!"

    Real Life 
  • The film The Hunt for Red October got some of it right: submarines are designed to be as silent as possible. In a situation where immediate silence is called for, the order given is "All stop, quick quiet", which means just what it says: the screws are immediately stopped, all communication is done by whisper or hand signs, and where you are standing is where you remain standing until the order is lifted.
    • Interestingly, diesel subs are in general much quieter than nuclear boats. That's because on the nuclear sub the reactor cooling must be on all the time, lest it suffers a meltdown, and cooling pumps tend to be quite loud. Also, being large and heavy contraptions, they are exceedingly difficult to completely isolate from the hull. Even with the newest reactor designs, where the cooling could be driven by natural convection on low power settings, the rush of coolant itself through the tubes creates a fairly loud hum, and the reactor is even more difficult to completely soundproof. Diesel subs, on the contrary, can turn off virtually all their systems in silent mode, the batteries or fuel elements are intrinsically silent, and electric motors on the low power produce virtually no noise. So the loudest sounds on a diesel sub would probably be from the crew moving around.
    • However, while a diesel sub can be quieter, it has to run at no deeper than periscope depth to run the diesel and recharge the battery, and can only run at depth for a limited time, until it becomes necessary to go back to periscope depth to charge the battery again. Nuclear submarines can operate submerged until the crew runs out of food, so despite being noisier than diesels, they have replaced diesels in the most advanced navies of the world. Newer diesel designs featuring various modes of air-independent propulsion (e.g. hydrogen fuel cells) have stretched their underwater operating time, however.
    • The standard U.S. Navy order is "Rig for silent running." Submarine personnel then go through a series of checklists in which equipment is organized to be as quiet as possible.
  • See this article. It was and to a lesser degree still is possible to move a whole strike fleet very close to the target if it doesn't give itself away. By the same token, planes may be run into an ambush where the first sign of a missile ship they see is a radar suddenly locking them from below.
  • In The '60s, the CIA realized they needed a stealth helicopter for infiltrating countries like North Korea or North Vietnam. Although building a completely silent helicopter was impractical, they took a standard helicopter and worked on reducing the noise signature of each component — modifications included replacing analogue components with early electronics and adding an extra rotorblade. Eventually, they came up with an aircraft that, when flown at a particular speed and nearly nape-of-the-earth altitude, was unlikely to be detected unless you were specifically listening for it. Possibly this one.
  • This has been a problem with electric cars and gas-electric hybrids: since their engines are so much quieter than those in gasoline-powered cars, pedestrians often don't hear them coming until it's too late. The US military, on the other hand, has been very interested in electric trucks and scout cars for the same reason, as such vehicles are quieter and stealthier than their gas-powered counterparts.