Cen's Guide to Roleplaying Sub-Surface Combat
INTRODUCTION
INTRODUCTION
Hello there, and welcome to Cen's Guide to Roleplaying Sub-Surface Combat! You're here (presumably) because you are interested in more accurately portraying the interactions between submarines in a combat setting. Or you clicked this link by accident. But whatever the reason, welcome! I hope you stick around, because I've put a lot of work into the guide, and I would love to see it help some of you to better write about combat beneath the surface of the ocean.
Sub-surface combat is a fascinating and oft-ignored theatre of warfare, where tiny mistakes can make a massive difference both for the relatively small number of people on vessels beneath the surface and for the millions residing in the global superpower thousands of miles away. Sub-surface combat is a game of stealth and careful maneuvering, not of raw firepower. It is fully possible for a totally outgunned combatant to gain the upper hand through knowledge of his own strengths and the enemy's weaknesses, careful strategic analysis, and a thimbleful of luck. I am making it my mission to help you understand all of the factors that go into prosecuting warfare beneath the world's oceans in a realistic and ultimately successful manner that will win the day on and off the battlefield. In addition to covering how to kill with submarines, I’m also going to touch on strategies that you can use in order to kill them. So let's get started!
I am going to systematically work through the topic of submarine warfare, starting with how submarine combat works from the perspective of a submarine, and then I'll address how to kill them.
WHAT AND WHY? — Submarines in the 21st-century battlefield
Let's start at the very beginning; what is a submarine? Simply put, a submarine is a vessel that is designed to move independent of outside assistance underwater. Submarines were first built in the 1700s, and have been a fixture of modern naval warfare since the First World War. But why do submarines hold such a position of importance, when they are comparatively small and less powerful than, say, a battleship? The answer is stealth. Battleships simply cannot sneak up on an enemy force that is actively watching the horizon for any sign of movement. Many modern-day submarines, on the other hand, can traverse entire oceans without ever breaking the surface. The tactical advantage granted by having an armed vessel capable of attacking from a position of secrecy in the midst of a decisive battle is immense, and quite literally turn the tide of the battle. Furthermore, if you manage to sneak a submarine under your enemies' noses without them noticing, it is fully possible to strike a decisive blow to your opponents without ever having to have a surface engagement.
Now, please do not take submarines to be a silver bullet that will win you the day in even the most unmatched battles. Since their first employment in warfare, navies around the world have come up with rather ingenious solutions that will negate the submarine's stealth advantage, the details of which I'll delve into a bit later. Submarines also have a number of inherent disadvantages, including their relatively light armament, the difficulty of resupply, the fact that you are literally UNDER THE WATER without access to air if anything goes wrong, and the simple psychological impact of spending days, weeks, or sometimes months underwater.
There are a number of different types of submarines with which you should be familiar before continuing forwards in this guide, so I will go ahead and explain them now. This guide focuses on attack submarines, which are the primary means of executing combat for a well-equipped nation. There are also ballistic missile submarines, which are generally used by nuclear-armed states as a means of power-projection and strategic deterrence, and, more recently, guided missile submarines, which have the capability to launch a staggering number of cruise missiles towards an opponent without risking a surface launch platform.
Submarines are further subdivided by their means of propulsion. For highly developed states, the general form of propulsion is a nuclear reactor, which provides a large amount of readily available and generally quiet power. Less-expensive alternatives are diesel-electric submarines, which use noisy diesel generators while surfaced and much quieter batteries while submerged. Lastly, and most recently, are air-independent propulsion submarines pioneered by the Germans, which use fuel-cells, large-capacity batteries, or generators that run independently of surface air to power their systems.
Now, there are a number of advantages to each type of submarine, as well as the accompanying disadvantages. I’ll start with diesel-electric submarines, the oldest type. Now, obviously, having two distinct forms of power supply seems a bit complicated, but it has been a system proven by decades of constant use. While surfaced (or at a shallow enough depth that they can extend a snorkel mast), these submarines run a diesel generator that allows them to recharge the batteries used for submerged or quiet running. When in combat or submerged, they use large batteries that allow them to be among the quietest vessels out there. Needless to say, running a massive generator is not the most subtle thing in the world, so diesel-electric submarines are generally limited to relatively coastal waters (or near allies) where they can safely refuel their generators when they need to. Diesel-electric submarines are generally the smallest type of submarines.
Nuclear-powered submarines, on the other hand, have no problem with power. They can happily operate for a decade or more without ever having to be refueled. There are a number of limitations that go with this form of power, however. Crews inherently become fatigued by quietly operating underwater for weeks at a time, and this can be a real issue, as a single careless act can lead to a fatal mistake. Secondly is the fact that, in order to safely operate, nuclear reactors must keep cool. This requires that a coolant pump be kept constantly running, which is white noise that nobody wants to hear when running silent. In quiet seas, this coolant sound can occasionally give the submarine away to a carefully-listening foe. On the other end of the spectrum, nuclear submarines can occasionally be too quiet; in noisy environments, a submarine can block out background noise by creating a sound shadow, referred to as a “hole in the water” contact. This can also give a submarine away to an observant opponent. Lastly is the simple fact that you are sailing around beneath hundreds of feet of water with a bunch of radioactivity powering your boat, and if something goes wrong, nobody is getting out alive. Because of the inherent size of a nuclear power plant, nuclear submarines tend to be quite large.
Lastly are air-independent propulsion (AIP) submarines, which generally apply to a class of vessels that use batteries, fuel cells, or non-air-requiring generators for their sources of power. These are a very new technology, and because I am not very well versed in their inner workings, I will steer away from addressing them.
Keeping these submarines straight can be a bit of a challenge, but conveniently acronyms are the answer! Each form of submarine can be identified through it’s manner of propulsion and purpose in a common format, laid out below.
SS= Common to all submarines; means “sub-surface”
N = Nuclear-powered
K = Hunter-killer (almost always diesel-electric or AIP)
G = Guided missile
B = Ballistic Missile
For instance take a nuclear-powered ballistic missile submarine. This would be abbreviated SSBN; SS for submarine, B for ballistic missile, N for nuclear-powered. Much more concise! Similarly, a nuclear-powered attack submarine would be SSN. Because AIP submarines are basically a subset of diesel-electric submarines, they do not have an individual designation.
Now that we have a working understanding of what types of submarines exist, I’ll address the weapons systems that make them unique and what makes submarines sometimes not the ideal choice for certain combat situations. But before I go into the myriad of weaknesses inherent so a submarine, I’d like to talk about its strong points, and how to get them to work for you in a combat setting.
WEAPONS SYSTEMS
In the First World War, many submarines’ primary weapons were their deck guns, essentially a ship-mounted tank cannon. The tactics used were to simply sneak up on a convoy underwater, surface, and then shell the ships from a safe distance until running out of ammo or running out of targets. This, needless to say, has evolved significantly, and the primary weapon of most submarines is now the torpedo. A torpedo is essentially an underwater missile that tracks its target via a number of methods in order to remove it from the battlefield.
Torpedoes kill their targets by detonating either underneath the keels of surface targets or by physically impacting the hulls of their quarry. This sets of a large amount of high explosive that is generally enough to at least disable a surface ships, and will generally sink a submarine.
Torpedoes are launched from submarines through pressurized tubes that penetrate the ship’s pressure hull and allow them to reload from inside the submarine and then fire the weapons on the outside. Most submarines have between four and eight torpedo tubes, with some rare exceptions. Because they are geared towards tracking down and killing other submarines and surface ships, SSKs tend to be on the higher end of the spectrum (6-8), whereas nuclear submarines that are meant for much more extended tours of duty and also commonly operate in an escort capacity have generally fewer tubes (4-6). And while I doubt you will ever consciously make your submarines face this issue, almost no submarines can carry more than forty torpedoes, and most carry no more than thirty or so. Most will carry ten or more.
Torpedoes are generally guided by a number of methods, which allow them to have the highest possible chance of hitting their intended targets. Almost all modern-day torpedoes stream a fiber-optic wire behind them which allows them to send sensor data back to the firing submarine and the submarine to send firing solutions and directions back to the torpedo. DO NOTE that these wires must be severed in order to reload the tube from which the torpedo was fired, as the outer door on the torpedo tube must be closed in order to load a new weapon. They can also be cut if the submarine turns too sharply away from the track of the torpedo; in this case only as little as fifteen to twenty degrees are enough to sever the wire. Once this occurs, the torpedo is on its own.
Speaking of which, torpedoes can also operate autonomously, with onboard computers allowing them to interpret the firing solutions loaded into them by the firing submarine and track down any contacts that its sonar seeker head may find. This can be through the use of active sonar — where the torpedo blasts loud *PING*s of sound and uses the echoes to locate a target — or passive sonar, where the torpedo “listens” to the sounds of propellers, propulsion systems, and more in order to home in on a target. Torpedoes can, given enough time by the fire-control people aboard the submarine, be programmed with certain specific tracks, such as traveling to a set point via a set route slowly and quietly before going active and accelerating to attack speed.
Now, torpedoes are not brilliant. They can’t be told “Go find the enemy!” and be expected to take out a super-carrier. That’s just ridiculous. In order to be accurate, torpedoes must be given the sonar information that the submarine has already gleaned, which takes time. This is generally referred to as a “firing solution”; it includes the tactical environment of the area, the bearing and location of the target, as well as any other necessary information. This takes time, sometimes as long as two to four minutes, and that time is an essential factor to work into your roleplay. If you simply fire in a general direction, torpedoes can still hit but are generally much less effective, as they have to do all the heavy lifting for themselves. As long as the guidance wires are intact, however, the torpedo can also be updated with new tactical information, retargeted, or even manually controlled from the control room of the submarine.
While they are a submarine’s primary weapons, torpedoes are generally not their only weapons. Most submarines have vertical launch system (VLS) tubes that allow them to fire cruise missiles as well, either against ground or naval targets. These tubes (usually no more than eight) can operate independently of the torpedo tubes, meaning that one could theoretically discharge eight torpedoes and eight missiles at the same time.
Danger: Launching missiles when sneaking up on someone is generally not a good way to keep quiet. Missile launches are exceptionally loud, and can be heard by literally everyone in the vicinity. They also leave a “flaming datum”, a visible smoke trail from the missile launch that leads right down into the water where the submarine is hiding. Missiles have to be launched from directly beneath the surface, which makes missile-launching submarines vulnerable to retaliatory strikes by aircraft before they can dive to safety.
With small enough missiles, it is also not unheard-of for small cruise missiles, surface-to-air missiles, or even mines to be discharged from a submarine’s torpedo tubes. Given enough preparation time, the tubes can also be used to launch and retrieve purpose-designed submersibles for such missions as conducting surveillance, investigating a wreck, or tapping an undersea cable. Note that the minisub would still have to fit within the confines of the torpedo tube in order to be launched or retrieved.
SUBMARINE COMMUNICATIONS
Now, one of the main weaknesses of a submarine, because it is constantly so far underwater, is that it is often very difficult to communicate with it. Instead of simply handing a captain orders and saying “Good luck, have fun, see you in combat in three weeks!”, there are a number of ways that can be used to communicate with a silent-running submarine.
The first is simply to define set times for the submarine to come to periscope depth and receive a message. This requires the submarine to break off whatever it is doing, including possibly tracking an enemy submarine, in order to come to periscope depth and stream a thin wire that can pick up an incoming VHF (very high frequency) message from a satellite. Unfortunately, in order to reply, the submarine must raise a physical mast above the water, which leaves a wake on the surface, and then transmit, which allows enemy units to listen in or simply home in on the source of the signal. Submarines therefore only rarely reply to messages if they have any interest in maintaining their stealth.
Another way for a naval command to contact a submarine is using a ELF, or extremely low frequency, transmission. These extremely long-wavelength waves can penetrate deep into the ocean and reach a cruising submarine. This disadvantage with this is that the information transfer rate is exceptionally slow. For this reason, most ELF messages simply advise the submarine to come to periscope depth at a given time in order to receive a VHF message, which can convey information much quicker.
Now, there is an obvious issue with submarines not being able to reply to messages from their superiors without giving away their locations. One way to rectify this is by using a message buoy. Submarines will often carry purpose-made buoys in their sails (no, they’re not conning towers!) with radio transmitters that can be released from underwater and pop up to the surface. From there, they can wait for hours or even days before transmitting, allowing the submarine to go to other locales and avoid giving away its exact location. This still tells the enemy that “Oh hey, there was a submarine here”, but it does not allow them to pinpoint the exact time when the submarine was in that specific spot. It also means that a submarine can communicate without coming to periscope depth, meaning that it could communicate information to allies during the heat of a battle without going to periscope depth by using a message buoy.
DETECTION SYSTEMS
Trying to navigate underwater has its own unique challenges, especially when you can’t simply look out a window and see where the next bend in the road is. This even more challenging when you are simultaneously trying to track another submarine that doesn’t know you’re there. Fortunately for you, generations of military scientists have tackled this issue so that you don’t have to.
The most commonly used means of tracking and navigation is the use of sonar (SOund Navigation And Ranging). Now, all of us who have watched The Hunt for Red October or read about sonar generally think about massive *PING*s, where the sound from essentially a gigantic megaphone on the nose of a ship bounces off objects and comes back. While this is generally used by surface ships that are already making a lot of noise, active sonar is also a great way to broadcast your own position to everyone within many many miles. For this reason, submarines (which are made for stealth, mind you) almost always use passive sonar. Passive sonar relies on highly-trained sonar technicians and high-tech computers to interpret sounds gleaned by listening to, not producing, sounds, and then finding out where they come from. A well-trained technician and an accurate computer can not only tell you where a surface ship is and how far away it is, but also it’s speed (by listening to engine note and blade counts, as well as the change in bearing), heading (again, change in bearing), and even distinctive traits that can allow you to identify the exact ship you are tracking (such as a shaft warble or uneven cavitation sounds). It’s a pretty amazing tool in the arsenal of a competent submariner, and allows them to have the upper hand in many combat scenarios.
Now for a quick history lesson. During the Cold War, Soviet and NATO submarines would frequently try to shadow each other, hiding in the sonar blind spot caused by a submarine’s profile and propellers in order to follow and, if necessary, be ready to destroy them. The fact that this blind spot existed on all submarines was a major concern, since ensuring the survival of their ballistic missile submarines in the eventuality of a first strike was crucial for both sides. Because of this, towed sonar arrays were developed, essentially an array of hydrophones that could be towed, or “streamed”, behind a submarine in order to negate the effect of the blind spot. Because these arrays were not connected directly to the hull, it also allowed them to be much more sensitive, thus increasing the ability of the sonar operators to identify potential targets, or “contacts”, at extreme range. Towed arrays were also applied to surface ships, with roughly the same advantages: pulling hydrophones meant that they were isolated from the sounds of the waves hitting the ship’s hull, machinery noises, or enthusiastic sailors belting out the national anthem.
Now, while I realize this is not the section devoted to Anti-submarine Warfare (ASW), I will talk about some of the systems used against submarines now, because submarines can also use them in certain circumstances. The first is MAD, or a Magnetic Anomaly Detector. These magic black boxes detect the earth’s natural magnetic field lines and use them to determine the locations of things such as seamounts or — in very specific and highly unusual circumstances — even submarines. Submarines generally use these for navigation purposes, as it allows them to “see” obstacles and maneuver around them. On the ASW end of the spectrum, submarine-hunting aircraft, or other submarines, can sometimes see the reactor compartments of motionless nuclear submarines, as they cause enough of a disturbance in the earth’s local magnetic field that they can show up on MADs.
LIDAR, a system that uses lasers to detect objects, is another tool in the ASW arsenal, and one that has a particularly worrying effect on the ability of submarines to operate in shallow waters. LIDAR can essentially bounce high-energy lasers off of objects that are at periscope depth or similarly shallow, and allow aircraft to detect them. This means that submarines much be very careful when coming to periscope depth that there are no sneaky ASW aircraft around. LIDAR has not been widely-used as a means of detecting submarines, largely because of the little time spent by submarines on or near the surface, but it does have the potential to be a game-changer on the part of a carefully-watching ASW aircraft.
SUBMARINE COMBAT
Now, at this point you may be saying to yourself, “Hey, wait a minute. He’s told me how to kill other people, but not how to avoid getting killed myself!” Well, you’re in luck, because it’s time to talk about how not to get your submarines killed! In addition to their stealth, submarines are equipped with a number of systems in order to allow them to survive in a battle once the torpedoes start flying. Unfortunately, the extent to which submarines do rely on their stealth as a shield does mean that the options are rather limited when it comes to an open fight.
The most rudimentary, but longest-serving, systems is a simple noise-maker, a device ejected from special dispensers in the stern of a submarine that release bubbles, hopefully drowning out the sound of the fleeing submarine and distracting any incoming torpedoes. These devices have a mixed track record with success, and can generally be ignored by advanced torpedoes.
More recently, countries have developed decoys which can move independently of their parent submarine and mimic it in order to draw torpedoes away from the actual target. These are launched through torpedo tubes and, just like torpedoes, cannot be controlled from the submarine’s control room once the outer door of the torpedo tube is cut and the guidance wire is severed.
Lastly, and most importantly, submarines have their stealth as a weapon. If they can manage to flood their tubes, open the outer doors, and launch torpedoes without being heard, they can generally quietly slip away or program the torpedoes so that the submarine’s location cannot be easily guessed.
If a submarine gets heard, of course, shooting off a quick shot in return and then running like hell can also be a reliable option. If running for cover is not the most reliable option, however, there are still some tricks that you can pull in order to avoid being blown out of the water.
The sad truth with submarine combat is that a multi-thousand ton submarine will never be able to outrun or outmaneuver a several hundred-pound torpedo, designed for the sole purpose of killing it. What it can do, in certain circumstances, it outsmart it. This is more difficult if the torpedo’s guidance wire is still intact, but can still be done.
Allow me to provide an example of how one might spoof a torpedo. You are tracking an enemy submarine, shadowing its path from several miles behind. Suddenly, your good friend Frankie from back in Jr. high drops a wrench down a ladder. Immediately, your good pal, the captain of the other submarine, hears from his sonar crew that there’s somebody sitting on his tail. He immediately fires a torpedo towards you. Now in normal circumstances, there would normally be two or more torpedoes, because it never hurts to overkill a submarine, especially when you aren’t exactly sure who it is behind you, but for the sake of this scenario, let’s assume he only fires once.
Now, you immediately fire off a couple of shots on your own, since you have acquired a decent firing solution. Then you turn and book it for the nearest seamount. Now, the torpedo coming after you is set on passive search mode, because your opponent was planning on swimming out a couple of torpedoes to kill your carrier group up ahead. So, it hears you going to flank speed and accelerates right towards you.
Fortunately, because of accurate navigation charts and a perfectly-functioning MAD, you have the tactical advantage in terms of terrain knowledge. You know that there is a boulder field directly on the southern side of seamount 712, and figure that if the enemy torpedo stays on passive search mode and you can sit near the bottom, totally quiet, among the boulders, it might pass right over you.
So, this is exactly what you do. As soon as you round the seamount and no longer have direct line-of-sight with the torpedo, you dive deeper and push the reactor to 110% in reverse. You manage to slow yourself to a near-stop seventy feet off the seafloor, and then go to all-stop. Then the torpedo comes around the seamount.
Now, you figure all is well. If everyone is really quiet, it should pass right over you and keep on going. But sadly, this is not the case. Today is not the best day for Frankie from Ms. Wormwood’s class, who drops the wrench again. Now, half the control room hears the wrench fall this time, and they figure all is lost. But you are too smart to give up just yet. You order weapons to open the already-flooded tube two, which contains one of your trusty decoys. It’s already programmed to sound just like your submarine with its valves slamming open and going to flank speed, so you give it a heading at give the order to fire.
Whoosh! Tube two discharges, and the decoy projects the sound of your submarine metaphorically flooring it. Because some nice man had the decency to take poor Frankie’s wrench away from him, the torpedo that was previously coming for your submarine is now heading for your decoy instead. If you sit there and wait, as quiet as the grave, until the torpedo and decoy have cleared out, there’s a pretty high chance that you’re going to make it back to port.
Now, notice how specific this situation is. If you didn’t have the information advantage, you’d probably be dead. If the enemy torpedo’s wire hadn’t broken, you’d probably be dead. If the torpedo had been in active search mode, there’s a 50/50 chance that it would have picked you our from among the boulders. If the enemy had fired another torpedo or two, you’d almost certainly be dead. There were so many factors that could have swung the other way and doomed you in this scenario, but because of your quick thinking and superior submarine, you made it out alive. And since you had a decent firing solution on the enemy and fired a couple of shots, there’s more than even money on you getting a kill out of this action to boot. Congratulations!
This is how you are going to have to think in order to take the tactical advantage in undersea warfare, especially when you lose the advantage of stealth and have to go in guns blazing. Once torpedoes are in the water, it’s less you against the enemy than you against time and the enemy’s torpedoes. If you can keep sonar contact on the enemy, that’s great. But if you can’t manage to survive their shots, there’s not much you can do about them. After all, if you’re sitting on the bottom of the ocean, you can’t really go back and take out whatever remains of your foe.
LIMITATIONS TO SUBMARINES
So, we’ve looked at some of the advantages that being in charge of a highly-advanced submarine has for you. Now, let’s look a bit closer at some of the limitations that also come with this.
Some of these have already been addressed; communication is a colossal pain in the rear, you have to be extremely quiet in order to not lose the stealth advantage, and you only have so many shots. Besides, if you make a wrong turn, you can lose control of your weapons, which may cost you the battle in the long run. We’ve also touched on the disadvantage of actually engaging in combat: It’s loud. Even something as simple as flooding your torpedo tubes can be heard in certain situations, which is why when many captains are expecting to go into combat, they will load, flood, and open the outer doors on any torpedo tubes they expect to use. Missile launches are even more noisy, and leave you vulnerable to attacks from above and below alike.
So, what could be worse? Well, your boat also has some severe technical limitations to consider. Firstly, you can’t usually get to the bottom of the ocean. Most modern submarines have steel hulls, because it’s a strong and relatively inexpensive metal that has stood the test of time as a hull material for submarines. But even for absurdly expensive titanium-hulled submarines like the Russian/Soviet Alfas, all submarines have a depth at which the water’s pressure exceeds the hull’s ability to exert outward force. This is called the boat’s “crush depth” for exactly this reason; it is the depth at which the hull is expected to literally implode, killing everyone in a blinding flash of heat as the air is compressed and everything combusts, and then a flood of icy seawater as the ocean rushes in.
Not a good way to go. Fortunately, every submarine also has another depth, the “test depth”, which they are not supposed to exceed. This is the depth to which the submarine has dove during its sea trials, and it has proven to be able to handle. Going deeper than the submarine’s test depth is gets you crucified by people up the chain of command and will endanger (if not severely damage) your submarine. Indeed, things start to get wonky as you even near the test depth. The deck may start to warp, interior water pipes may burst, steel beams may bend. The water has an absurd amount of force behind it pressing inwards on you when you’re that deep, and it can do humbling things to an unwary seaman. So, good rule of thumb is to not go to your test depth, and to never consciously exceed it. Otherwise you die. And lose a submarine. And who wants that?
Here’s a slightly more cheery disadvantage to submarines: They don’t actually have a ton of firepower. Sure, torpedoes are lovely, and sure, given advance warning and a good bit of luck, you could technically attack an enemy surface fleet with ten torpedoes and eight cruise missiles at the same time. But chances are, three to five of those torpedoes are going to miss, and three to five of those cruise missiles are going to get spoofed, jammed, or shot out of the sky. So unless you’re working in tandem with a much broader attack, whether another submarine or two or a coordinated airstrike, you’re unlikely to be able to destroy an entire battle group with a single badass submarine captain and crew.
Oh, and even if you do, there’s a 90% chance that you are going to die in the process, because there are a good deal of anti-submarine weapons that will be able to track you down and remove you from the battlefield. Even if you RP like JRR Tolkien wrote fantasy, there’s no realistic way that you’re getting out of there alive without half the rest of the RP looking at you and saying, “Godmod much, m8?”
Finally, you’re kinda squishy. What I mean by this is that even a light-weight torpedo launched from a circling helicopter can send you to the bottom. When the only thing keeping the water out and the air in is a couple of inches of wiring and steel plating, a nice-size explosion can easily kill everyone on board within a couple of minutes. And even if the flooding doesn’t immediately kill everyone, the submarine is headed for the bottom, which is generally well past its crush depth. Not a pretty way to go.
The solution to all this is, of course, avoid getting shot at yourself. In order to do that, it is very helpful to be able to understand the tactics and weapons that are being deployed against you by your opponents on the surface and in the air. Which brings us to anti-submarine warfare.
ANTI-SUBMARINE WARFARE
Because of their ability to sneak around quietly, the best weapon against a submarine will likely always be another submarine. But for a surface fleet commander who knows they are likely headed for a snake’s den full of hostile submarines and don’t have the luxury of a sizeable submarine escort, it is very helpful to understand what sort of tricks can be used to avoid getting sent to the bottom of the ocean, courtesy of the business end of someone else’s torpedo. This is the art of ASW, or Anti-Submarine Warfare.
Because surface ships generally don’t have the advantage of stealth, they are free to use their active sonar arrays with much less fear of being sunk as a result. For his reason, many surface groups that are traveling through waters containing suspected enemies may use their active sonars nearly constantly in order to pick up marauding submarines.
Unfortunately, sound waves don’t pick sides. This means that if a surface fleet is being escorted by submarines and starts blasting active sonar, it could have the totally opposite effect from the one intended by actually revealing the location of allied submarines, and in many cases doing so without revealing the enemy submarine as well. This is one of many reasons submarines tend to maintain a respectful distance of surface groups, as it allows them to operate independently of their comrades on the surface without fear of being compromised by the itchy trigger finger of a sonar technician.
For obvious reasons, the primary weapon used against submarines by surface ships and aircraft alike is the torpedo. Because they lack the same immense size constraints of submarines, torpedoes fired from surface vessels can be larger and longer-range than comparable units fired from below the surface. Surface ship torpedoes are also generally fired from on the deck, out of specialized launchers that cant outwards away from the ship instead of from beneath the water.
Another system used against submarines is the ASROC, the Anti-Submarine ROCket. ASROCs are a standoff ASW weapon, meaning that they can be deployed for use at a much longer range than conventional anti-submarine weapons. The weapons essentially missile-mounted torpedoes, and can fire up to twelve miles away from the ship before the torpedo is released from the missile, deploys a parachute, and drops into the ocean, and then hunts down any submerged contacts that it may find. This gives surface ships an immense advantage in terms of range, because they can essentially drop a torpedo on top of an enemy submarine while the submarines have to wait for their much slower torpedoes to reach their targets.
Now, all of this offensive technology is difficult to use if you have no idea where a submarine is, or even if one is following you at all. For this, helicopters and maritime patrol aircraft are an invaluable tool for the competent tactician. Helicopters can be equipped with dipping sonar, an active/passive sonar than is spooled down from the helicopter on a wire into the ocean before being picked up and moving on, magnetic anomaly detectors and LIDAR arrays (see the last two paragraphs in the detection systems section above), and even lightweight torpedoes. These helicopters, depending on the type of aircraft and the surface platforms in question, can be operated from onboard the surface vessels themselves, giving the ships an essential first line of defense against marauding submarines.
But helicopters are not the only aircraft that can be used to attack submarines. Fixed-wing aircraft — know in this context and usage as MPAs, or Maritime Patrol Aircraft — can also be used, can carry roughly the same array of sensors and weapons as helicopters. Unfortunately, because they obviously can’t hover in one spot, MPAs cannot carry dipping sonar, but instead carry sonobuoys. These are similar to submarines’ message buoys, but in reverse: they carry miniature sonar arrays that transmit their data directly back to the aircraft for analysis and possible action. MPAs also don’t have quite the size restrictions of helicopters, and can therefore carry large computers for analyzing sonar data and the technicians necessary for interpreting the computers’ analysis and acting on it.
For virtually all ASW platforms, another valuable tool is infrared detection. Submarines are generally warmer than their surroundings, so if a submarine breaks the surface with a mast or part of its sail, carefully watching submarine-hunters can spot it with infrared scopes and possibly respond.
PHYSICS IN SUBMARINE WARFARE
Now, while the word physics alone may make the student inside each of us shudder a little bit, having a working knowledge of what the laws of nature decree is necessary in order to accurately roleplay complex interactions between enemies underwater. For this reason, I’m going to give you a primer on submarine physics, as relevant to combat underwater.
The first think you should know about are these wacky things called sound speed gradients. Because the ocean is not uniform from the surface to the seafloor — because of currents, temperature differences, changes in salinity, increasing pressure, and even different levels of biological activity — there are horizontal layers that form at certain depths that have a massive effect on passive sonar surveillance. An example of this is the thermocline, where there is a rapid temperature change between the water above and the water below. Because of their unique characteristics (such as density), these layers can reflect sound, meaning that submarines above the layer may not necessarily be able to hear submarines below the layer. The opposite can sometimes be the case in the horizontal axis, where the layers can focus otherwise faint sounds on an area for away in the same layer, allowing any submarines at that distance from the source of the sound to momentarily hear it much clearer than other sounds. This can be an extremely useful for submariners, as they can hide below a layer in wait for surface ships and be relatively noisy without fear of being heard. Fleeing submarines can also hide above or below a layer, momentarily hiding them from the sonar scopes of chasing submarines or torpedoes. While these layers do effect active sonars, this is to a much lesser extent than passive sonars.
The massive changes in pressure underwater also cause negative effects for submarines in terms of ambient noises. As a submarine’s hull expands and contracts due to changes in pressure caused by gaining or losing depth, the hull can make distinctive “popping” noises. These hull pops are very useful for determining if a target is changing depth, but can also give a submarine away if they are heard by a listening sonar operator.
One more important thing to note is cavitation. Cavitation refers to the formation of tiny bubbles on the trailing edge of a submarine’s — or even a surface ship’s — propellers. The popping of these tiny bubbles makes a hissing sound that can be one of the most definitive pointers to the presence of a submarine in a region. Propellers do not general cavitate until the vessel is traveling around twelve knots or higher, although some submarines equipped with a pump-jet can go faster without risking cavitation.
CONTROL ROOM LINGO
Now that you have a handle on what you are going to do in your submarine battle, the next thing to do is learn some relevant, realistic, and — most importantly — understandable technical jargon to your roleplay. I’ve formatted this list of jargon in an alphabetized glossary, so if you see something referred to that you do not understand, simply look for the relevant entry detailing it. Words in italics indicate that they have a separate entry. This details primarily specific terms used in a combat setting, and generally does not list terms defined in the above sections.
Ballast Tanks: The primary means for submarines to change depth; large tanks that can be alternately filled with seawater or compressed air in order to increase or decrease depth. Submarine generally have bow and stern ballast tanks.
Bearing: An angle relative to true north that is used to navigate or target weapons, measured with 0 degrees being north and proceeding in the clockwise direction. For instance, a submarine traveling at a bearing of 90 degrees is travelling due east.
Conn: The individual who “has the conn” is the one who currently has control of the submarine, and can sometimes be referred to as the “conn” in scenarios where distinct communications are necessary between two people.
Contact: Noun; a definitive entity that has been detected by the a vessel’s sonar. Contacts are generally numbered in the order they appear, for instance the 23rd contact made by a submarine during its tour could be “Master 23”. This serves to keep contacts distinct from one another in a chaotic situation. Other nouns can apply in the place of “master” when designating contacts.
Diving Planes: Fins extending from the bow of a submarine (usually) that allow it to change depth without the use of the ballast tanks. Often referred to as “planes”, or the “bow planes”. Changes are measured in angle, for instance putting a ten-degree up-angle on the bow planes inclines them towards the surface by ten degrees, making the submarine lose depth.
Firing Point Procedures: The act of preparing a firing solution for being loaded into a torpedo.
Firing Solution: The targeting data necessary for a torpedo to operate in a well-informed manner. Firing solutions are highly recommended in order to improve accuracy, but torpedoes can also simply be fired down a certain bearing and be left to locate a target on their own.
Fish: Quick way to refer to a torpedo, usually hostile or fired by an allied unit. Torpedoes fired from the submarine are generally referred to as units.
Hot: In addition to being a temperature, “hot” refers to an outbound weapon’s arming status; a “hot” torpedo has an actively armed warhead.
SCRAM: A SCRAM is an emergency total shutdown of a nuclear reactor. Ideally, you will never have to do this, because it takes a very long period of time in order to regain the necessary heat for propulsion after a reactor scram.
Turns: Turns refers to the rotation of the vessel’s propellers. For instance, an order to “make turns for ten knots” would mean that the helmsman would change the speed of the propeller’s rotation in order to bring the boat to a new speed of ten knots.
Unit: Quick way to refer to a torpedo fired by the submarine. Hostile torpedoes or torpedoes fired by allied units are generally referred to as fish.
Bearing: An angle relative to true north that is used to navigate or target weapons, measured with 0 degrees being north and proceeding in the clockwise direction. For instance, a submarine traveling at a bearing of 90 degrees is travelling due east.
Conn: The individual who “has the conn” is the one who currently has control of the submarine, and can sometimes be referred to as the “conn” in scenarios where distinct communications are necessary between two people.
Contact: Noun; a definitive entity that has been detected by the a vessel’s sonar. Contacts are generally numbered in the order they appear, for instance the 23rd contact made by a submarine during its tour could be “Master 23”. This serves to keep contacts distinct from one another in a chaotic situation. Other nouns can apply in the place of “master” when designating contacts.
Diving Planes: Fins extending from the bow of a submarine (usually) that allow it to change depth without the use of the ballast tanks. Often referred to as “planes”, or the “bow planes”. Changes are measured in angle, for instance putting a ten-degree up-angle on the bow planes inclines them towards the surface by ten degrees, making the submarine lose depth.
Firing Point Procedures: The act of preparing a firing solution for being loaded into a torpedo.
Firing Solution: The targeting data necessary for a torpedo to operate in a well-informed manner. Firing solutions are highly recommended in order to improve accuracy, but torpedoes can also simply be fired down a certain bearing and be left to locate a target on their own.
Fish: Quick way to refer to a torpedo, usually hostile or fired by an allied unit. Torpedoes fired from the submarine are generally referred to as units.
Hot: In addition to being a temperature, “hot” refers to an outbound weapon’s arming status; a “hot” torpedo has an actively armed warhead.
SCRAM: A SCRAM is an emergency total shutdown of a nuclear reactor. Ideally, you will never have to do this, because it takes a very long period of time in order to regain the necessary heat for propulsion after a reactor scram.
Turns: Turns refers to the rotation of the vessel’s propellers. For instance, an order to “make turns for ten knots” would mean that the helmsman would change the speed of the propeller’s rotation in order to bring the boat to a new speed of ten knots.
Unit: Quick way to refer to a torpedo fired by the submarine. Hostile torpedoes or torpedoes fired by allied units are generally referred to as fish.
Please note that this is by no means a complete list! I may be adding to this list as time goes on or as people bring new items to my attention, and many items are excluded from this list because I either don’t know them, didn’t think of them, or don’t use them. Research of your own can be very helpful in coming up with specific terms unique to your submarines.
APPLICATION
The next major question to ask is, what does all of this information look like in the context of roleplay? You will likely not be giving a tour of your ASW assets to some foreign dignitary, but you will be using them to write realistic combat scenarios. This can take a variety of forms — and I highly encourage you to explore! — but here is an example of some of my writing in which I apply information included in this guide.
Do note that this was written according to my knowledge of American (and generally Western) submarine control room procedures. It may bear little relation to what procedures may look like in your country, depending on your culture, military hierarchy, and other factors. For this reason, I encourage you to look at this only as an example of how terminology and submarine warfare knowledge can be applied to a scenario, not how the actual character interactions take place.
The Nation of Ceneria wrote:Aboard CNS Stormcry, SSN 471
364 kilometers off the Qiraji Coastline
1500 HoursFar beneath the swells, a black shape slid her way through the dark water. The Cenerian submarine was utterly silent, nary a sound coming form her ninety-meter form. The eyes and ears of the boat inside the sonar room were all trained outwards, listening for anything to betray the presence of the enemy. The Stormcry cruised sixty feet off of the bottom at just over five knots, gently pulling her exceptionally sensitive towed array behind her metallic bulk.
Inside the control room of the hunting Sealord-class SSN, quiet voices reported everything that moved outside the steel and ceramic hull. A dozen men watched over every aspect of the boat, from the sensitive electronics and nuclear reactor aft to the way that she cruised through the silent ocean.
Suddenly, the professional silence was breached. "Conn, sonar! transient contacts on bearing 137, sound like torpedo tube doors opening! It's through the layer, but it sounds like a range of about 3000 yards!"
Captain Franklin Hoffmann whipped his head around, staring at the wall of the control room in the direction of the contact. To the messenger standing behind him, it seemed as if he were staring through the very hull of the submarine itself at the enemy.
"Helm, bring us to course 140. Five degree up-angle on the bow planes, make turns for six knots. Weapons, what have we got loaded?"
The weapons officer of the submarine spoke quietly. "Tubes one through five loaded with Mk. 53 ADCAPs, six with a Brilliant decoy."
"Fire control, I designate contact Master One. Weapons, ready tubes one through four in all respects, including opening the outer doors. Target on bearing 137."
"Tubes one through four ready in al respects, sir."
"Conn, sonar. Coming through the layer in five seconds."
Hoffmann counted down slowly inside his head, and then waited for the sonar officer to report.
"SHIT! Conn, sonar, torpedo launches on bearing 137, match with Qiraji Black Shark torpedoes! I count four, five, six fish in the water, all on bearings for the fleet."
"Weapons, load firing point solution on Master One and fire when ready."
"Aye, sir." A moment later, he nodded to a work over his headset and spoke again. "Firing tubes one through four now. One away. Two away. Three away. Four away. All units in the water, running hot, straight, and normal, sir."
"Reload tubes one through four, Mk. 53 ADCAPS, weapons. Helm, make turns for nine knots, level on the bow planes. Take us to course 165."
"Aye, sir. Zero angle on the bow planes, coming to course one-six-five. Increasing speed to nine knots."
"Conn, sonar!" screamed the sonar officer again. "Two new contacts, on bearings 134 and 139 respectively! Both Kilo-class submarines at periscope depth! Missile launches, I count twenty launches!"
"God have mercy on their souls," murmured Hoffman. "Designate contacts Masters Two and Three respectively. Weapons, target unit from tube three on Master Two and unit from tube four on Master Three!"
"Conn, sonar! Designate Master One as Scorpène-class SSN, same bearing, range now 2200 yards! She's making turns for sixteen knots, and heading towards the coastline! Going deeper, sir! Annnnd, lost her below the layer! Accoustics match with the Nahang, sir."
"Helm, five degree down-angle on bow planes, come to course 140! We don't want to lose that bastard."
"Conn, weapons. Lost guidance wires on tubes one through four.
"Sir," the sonar officer said, "Torpedo launches from Masters Two and Three! Eight torpedoes in the water, all on our bearing! Masters Two and Three are turning and going to flank speed, sir!"
"Weapons, fire the Brilliant decoy in tube six on bearing 340, programmed for Sealord-class submarine going to flank speed. Reload tube with ADCAP."
"Tube six away, sir! Unit running straight and normal. Going to active, now."
"Aspect change on the inbound weapons! Six are turning and following the decoy!"
"Yes!" Said Hoffmann to himself, before returning to the task at hand. "Weapons, launch noisemakers please.
"Noisemakers away. Tubes one through five now ready in all respects, sir. All loaded with ADCAPs."
"Conn, sonar. Inbound fish falling behind, heading for the noisemakers. Two detonations, sir." The sonar officer waited for the sound of the reverberating explosions to dissipate, and then spoke once more. "Asses both trailing units destroyed, sir. They hit each other."
"Sonar, what is the condition of our weapons?"
"Units from tubes one and two are still running normal, probably trailing Master One. Unit from tube three is… Shit. Lost it to a decoy. Unit from four, I can't hear. Wait… Sir, torpedo detonation on bearing 147, assess as unit from tube four! Hull popping sounds, sir! Assess Master Three as destroyed!"
"First blood." Murmured Hoffmann under his breath. Several men in the control room cheered. "Quiet in control!" snapped the captain then, narrowing his eyes. "There are still two of them out there. Sonar, what do you have on Master One?"
"Nothing sir. The torpedoes are still running, but aren't trailing anything. Master One got away, sir."
"Damn it!" Hoffmann cursed. That Scorpène-class SSN would have been a huge prize for the Stormcry. "Sonar, condition of the enemy weapons?"
"Torpedoes are still running normal, but I can't hear the missiles."
"Right. Keep your eyes peeled for Master One, sonar. She's quite a sub." I'll bet she's waiting on the bottom for us, he thought to himself.
"What about Master Two, sir?" Asked the weapons officer.
"Let her live to fight another day. Master One is a far bigger prize."
"Aye sir."
"Weapons, torpedo room conditions?"
"All tubes loaded with Mk. 53 ADCAPs. The men are in high spirits, but ready for anything, sir."
"Good. We may yet get a fish on our tail." Hoffmann turned to the navigation table behind him, and stared at the electronic map of the seafloor. The map now showed icons for all of the confirmed contacts, including the wreckage of Master Three and the outbound Black Shark torpedoes. He scrutinized the topography of the seafloor.
"Helm, zero-bubble on the planes, come to course 153, slow to four knots."
"Aye, sir. Zero-bubble on the bow planes, coming to course one-five-three. Slowing to four knots."
"Now," he said quietly, "Where are you, Nahang?"
CLOSING REMARKS
Well, thank you for bearing with me through that extremely lengthy guide! I very much enjoyed writing it, and I can only hope that you have learned something from it.
Despite its length, it is highly likely that I’ve forgotten something important and probably a bit silly. If you manage to think of something you think I should address, please feel free to post here and let me know so that I can rectify that issue. If you also totally disagree with me about something I have written, please let me know so that I can try to fix any issues there may be.
Now, if you read this guide and then miraculously manage to use it in your own roleplaying, I encourage you to post a link or quote yourself in this thread. I would love to read what you have written and know that I somehow made a difference!
Hopefully, reading this will prepare you to write high-quality role-play posts involving submarine combat. But while this guide is a useful resource for reference and learning the basics, I do encourage those interested in the topic to delve deeper into submarine warfare. It is a fascinating sphere of combat, and one that I have thoroughly enjoyed reading and writing about. In order to further improve your own writing, I would highly recommend conducting your own research, whether by reading technical manuals or novels about submarine combat, and apply the lessons you learn there to your own writing.
Again, I hope you’ve enjoyed reading this guide as much as I have writing it, and I look forwards to hearing your remarks and reading what you have written as a result of this guide! Cheers!
