Range-finding and Fire Control - Plotting Your Demise

[Music] [Music] so ranging and fire control systems for your anti-ship guns well when it comes to that time in one's life when you really want to blow someone up but you don't have a plane and they're honestly a bit too far away for a grenade or even a trebuchet this is when you need to break out the artillery now owning artillery is one thing actually getting it to hit something is another and since people don't like being blown up they have this annoying habit of moving to get out of the way there's so even simple trial and error around a fixed point doesn't work very often and given enough time these people also tend to find their own artillery to try shooting back this holds true as much as at sea as it does on land except for one further complication when you put your artillery on a ship it's a very moving experience and once the significant emotional event is over the ship also turns out to be underway whereas on land at least most of the time your position is still roughly the same before and after you fire your guns and if it isn't well usually something's gone very very wrong and the finer arts of ballistic calculation are no longer your concern but when the day is going a bit better in order to hit your opponent you need two basic systems range-finding and fire control a range finding is the first important thing because anything other than effectively melee range when we're talking about ships your projectile is going to fall fairly significantly under gravity and this is basic ballistics to counter this you need to elevate your gun so that the ark described while your projectile intersects with the target instead of the sea at least if you're not the interwar French or Japanese and in order to do this properly you need to know the properties of your gun and the projectile which hopefully you've worked out somewhat sooner than when you need to use it in actual combat and you need to know how far away the target is in order to determine at the range and thus how far you need to elevate your gun fire control is the next thing in its most basic form fire control just tells you when to fire again back in the age of sail this really only had to factor in two issues once the range had been established bearing and roll bearing because unless the gun was actually pointed at the target you might drop lovely shots for or after the enemy which might doubt them in a refreshing spray of seawater a but little else role was important because the guns were fixed to carriages which with any luck were staying firmly on the deck and so if the ship was rolling then where the gun was pointing at any given time in the vertical element might change and the vertical component that was imported to the projectiles velocity might also cause it to go further or shorter than you'd counted on time the firing on the roll right and you'd hit the target and time it wrong and you just irritate them although you could exploit this effect as well French ships and many Raiders in the age of sail would tend to fire on the upwards role which made their shots trend a little bit high to cut up enemy rigging british ships as well as other ships with a more militant outlook tended to fire on the downwards role so that more of the shop would trend towards the lower part of the enemy's hull knocking out guns and crew as well as opening holes near the waterline a secondary effect of a good fire control system is to allow you to choose how many guns to fire at once and in which order this could allow you to do in the age of sail a rolling broadside a full broadside all some partial broadside or any number of permutations thereof this in turn allows you to control the number of variables in both adjusting your own aim and dictating what kind of effect your fire will have on an enemy now back in the good old days of the age of sail all this range finding and fire control was done using the good old human brain and eyes in the latter part of the period some enterprising individuals even put some basic iron sights on their guns this was largely down to the relatively short range of these cannon on a good day you might get about three miles range if you wanted to pretend to be a slightly lower angled version of a mortar but generally speaking cannon ranges of a mile or less were common and binocular vision of humans combined with a brain that is relatively good at simple ballistics would suffice to work out how far away they were and how much you need to shoot them plus he generally had quite a few cannon so if you were really unsure a couple of ranging shots to calibrate the old noggin weren't that much of a problem and so engagement ranges would typically take place at a few hundred yards where the problems began with the invention of armored ships because an armored ship needed a more powerful gun to punch through the armor a more powerful gun could also send a projectile further and one of the best ways to counter the more powerful projectile apart from just slapping on massive amounts of thicker armor was to simply move further away where the decreasing velocity of the projectile would decrease the amount of armor it could penetrate and thus you didn't have to increase the armor quite so much in order to stay intact the problem with this was that it ran into the problem of parallax unfortunately parallax was not at this stage at least a DC supervillain but rather a limitation of the human body the reason that we're quite good at working out the distance to things in general is due to our binocular vision which we mentioned earlier each eye sees a slightly different broadly similar image due to both eyes facing forward but being a few inches apart this means that an object at a certain range will seem to be in one place to one I relative to its surroundings and in a slightly different place to the other eye this is parallax the difference in angle between the two points of view causes a shift in the apparent location the greater the difference in angle the greater the shift objects that are closer have large differences in ankle objects that are further away less so and our brain is able to process these based on the amount of muscular tension it needs to use to focus the eyes on a particular object resolve the differences and thus estimate a given range this works great a few yards a few dozen or even a few hundred but once you start talking the order of thousands of yards or more to be honest anything much about five or six hundred yards in most people's cases the relatively small distance between our eyes leads to very tiny variations in apparent angle and past a certain point the brain can't really process the resulting tiny differences with any real accuracy or meaning this is why for example the moon planets stars satellites and the space station all seem to be roughly the same distance above us in this kind of dome thing and slightly closer range why looking a couple of airliners high up in the sky might give the appearance that they're going to collide only for one of them to apparently slide over the other as it turns out they're actually several hundred or several thousand feet apart in height applied to ships the human minds ability to judge range unassisted began to fall away a lot sooner than the ultimate range of the guns themselves this is why in the 1870s even with relatively low angles of elevation guns could reach out to between six and nine thousand yards they hit ten thousand yards quite comfortably by the 1880s and fourteen to fifteen thousand yards and in some cases more by the 1890s but by the end of the 1890s in the spanish-american war battles were still being fought at between one and three thousand yards for the most part and even here well to be perfectly honest accuracy was more luck than judgment the lower end of this range actually being comfortably within the capabilities of a late 17th century ship-of-the-line albeit that was at the age of sale t prefer to fight a bit closer where at all possible there are examples from that particular conflict which happens to fall at just the right time that show two ships with otherwise relatively decent gunnery crews blazing away at each other at just a fraction over a thousand yards and scoring minimal to no hits and so the need for a different way to estimate the range was needed simply firing salvos based largely on guesswork and then trying to correct based on the splashes wasn't too useful either since the splashes from the Salvos would be subject to exactly the same problems at guessing are their range as were being encountered guessing the range to the target ship itself albeit the you could at least tell if you'd gone over or short of the target although by how much was very difficult to judge and to be honest with this slow rates of fire of heavy guns at the time an enemy that held his fire whilst you wasted a salvo or two on long-range speculative shooting could probably wander up close whilst you were in the process of reloading and then drop a far more accurate salvo on you in the meantime at point-blank range now unfortunately human eyes don't really do that well when put outside of their sockets and genetic hybridization with the hammerhead shark is frowned upon so simply having a human's eyes be further apart was not possible instead a mechanical aid had to be devised the rangefinder there were two main ways of doing this in by the late 19th century optically and via depression the latter option was only really useful in land-based coastal defences and it wasn't anything to do with using officers who had an especially bleak outlook on life but rather it was to do with trigonometry at least after some early experiments that proved somewhat difficult and unreliable in working out their results you would mount a scope of some kind with a known focal range at a fixed height above the sea you would then look at the target focus the view so you could see it clearly and read off the focal length of the scope and the vertical angle that you had used this gave you the hypotenuse of a right angle triangle as well as two of the angles the angle of the depression of your scope and a right angle triangle which was the intersection of where you were with the C since you already knew the short length of the triangle which was the height that the scope was mounted above the C you could then use a set of fixed pre-calculated tables to work out the longer length which was thus the range you would then adjust for curvature of the earth the state of the tide and then fire your gun ideally the shell would land on or near the target and you could pick in corrections but this only worked when the height between the observer and the C was known fairly precisely when you were actually at sea on a ship that was rolling pitching and at any given time would have a varying freeboard and draft this information was not possible to acquire in real time rendering the method useless the optical method held far more promise for ships at sea this exploited the same trick that our brains use for close range calculations but due to being a machine it was much simpler to move the two eyes or points of reference further apart in this increase in base length between observations also naturally increase the apparent angles between the two observations and thus an object further away could be observed and have the range accurately calculated because the difference in viewing angles were still significant enough to calculate a good result obviously the wider part the lenses and prisms the longer the range could be calculated at and the more accurate readings would be derived at ranges that were closer in for example much later at the Battle of Jutland it would be noted that ships that were fitted with wider based range finders consistently showed more accurate shooting than ships with shorter range finders and despite the ranges in question being theoretically within the capabilities of either system the technical limitation was manufacturing precision as even the smallest error in the prisms the lenses the tube the various gears etc would be significantly amplified if it had to be propagated over a considerable length such as say a 20 or 30 foot wide range finder a human was still needed to operate these systems though and they were two main ways making this technology work the coincidence and stereoscopic methods the coincidence method works by having a a very fine optical prism at each end of the rangefinder mounted by default to look absolutely true forward when you point the rangefinder at the target because of the distance between the two prisms the two images they project are obviously in slightly different places effectively what you actually see before your brain compensates in you normal vision in the coincidence rangefinder these two images are presented either overlaid atop each other or in most naval examples the upper half of one image is placed above the lower half of the other and causing the two halves to appear offset as this difference is both easier for the human eye to adjust to and also easier for the brain to recognize slight differences in as compared to two completely overlapping images the other method devised somewhat later on actually projected the same top half of the image from both prisms with one inverted at the bottom as it was felt that perhaps this common element would help alignment even more now the operator had to turn a compensated dial which adjusted the angle of a lens that was contained in one of the arms this changed the angle of the projected image and thus moved it across the eyepiece the operator would continue to adjust this dial until the two halves of the image aligned this recreates the same situation as depression rangefinder except flipped 90 degrees on its side now the known base length of the rangefinder is the short edge of a 90 degree triangle and the two angles at this point also no one is obviously 90 degrees the other is whatever angle the dial on the compensator lens that you just adjusted tells you using the compensator lens also has the added advantage of not having to actually adjust to the angles of the delicate prisms and lenses at either end of the rangefinder and you're simply turning a relatively small and fairly practically corrected geared lens within the system itself now using the sine and cosine formulas you can work out the length of the hypotenuse and the long edge of your 90 degree triangle and the latter the long edge being the range to the target because this relationship is a known set of mathematical values a simple geared dial could be connected to the compensated dial which could immediately tell you what the range you'd adjusted for was without having to consult a table in a book this is why although the system itself only needs a single viewing lens some of the more common naval range finders such as the bar and Stroud set which supplied a good chunk of the Royal Navy's needs throughout the early part of the 20th century included a second viewing lens which holds this arranged dial so the operator can see and read off of the range as he adjusts the view in the scope the system would prove to be relatively simple and robust and users of decent 35 millimeter film cameras will also be familiar with exactly how this system works yet had its weaknesses it relied on the human ability to marry up common reference points and so could be confused by making the ship's outline very irregular hence the weird triangles that briefly appeared all over British ships in World War one and of course precision was based on a steady hand of the operator and enough distance between the lenses so that only a specific angle of compensation would give an aligned image as opposed to a range of similar angles if the tube everything was in expanded or contracted all that much with heat or cold this would also throughout the readings as it would change the base distance and of course a vibration could throw out the prism alignments or make it impossible to distinguish a clear image it was also for rather obvious reasons not brilliant against fast-moving targets that jump around a lot or are particularly difficult to track such as aircraft the alternative method was the stereoscopic rangefinder now this exploited the human eye and brain considerably more in its innate functions and the coincidence rangefinder by effectively acting as a way to widen the space between the observers eyes directly in aid of this identical markings were placed on each lens at each end of the rangefinder these would serve as a reference points the observer would then look through two eyepieces one connected to each lens and prism and he would see two slightly different images of the target the brain would automatically adjust these to form a single clear picture of the target as if the brain is want to do assuming of course that the operator had 20/20 vision now the marks would come into play because of the brains habit of matching aligned identical images to form a 3d picture though the brain would also try to align these marks into a single image and the rangefinder now exploited a trick that you can try yourself if you have two dots side-by-side on a piece of paper that separated so that one eye can't see the other dot such as a bit bit of cardboard or something then bring the paper close enough to your face and try and relax and stare off into the distance your brain will think it's actually seeing a single object at different angles and will then project a single dot at a given distance that you can focus on it can take a few minutes to make this work now if you do that with another pair of dots slightly further apart on the same bit of paper the two projected single dots as you focus on them will appear to be at different distances again because you're tricking the brain now of course in reality both sets of dots are on the same bit of paper at the same distance whereas on the rangefinder the target is at one distance which is the one you want to find and the marks on the lenses are fixed but due to this illusion effect the brain will merge the marks and project them at a given obviously false distance this distance can be determined prior to battle via calibration of the system now if these two apparent distances are different the brain can focus on one or the other but not both and the one that's not being focused on will appear to be blurred or doubled and so the operator can adjust a compensation dial similar to the coincidence rangefinder until it's possible to focus on both marks which usually a diamond-shaped and the target at the same time now the apparent range of the marks matches the actual range to the target and using the pre calibrated figures built into the compensator dial the range can be determined by the amount of angle that the lens had to be adjusted to to get the marks to focus at the same apparent range as the targets at this system was not vulnerable to breaking up the ship's outline with jagged devices indeed doing so with this system actually gives more points of reference for the brain to calculate on actually making it easier to range on the target in certain aspects and it can also be more easily used against fast-moving targets like aircraft as you can just zoom out and then track easily enough since there's no manual alignment of images required you just twist the dial to make sure that everything stays in focus and they were down sights though the operator required excellent vision to start with and of course was constantly having to switch between in and out of focus images a bit like someone constantly slapping multiple different prescriptions of glasses over your face every few seconds while you desperately tried to focus on a fixed object understandably this would lead fairly quickly to massive ice strain and an absolutely screaming migraine sooner or later albeit that some people were better suited to this particular role or than others unlike the coincident system the wider the rangefinder the better the results although a wider base on your rangefinder meant a narrower specific focus field which then meant more strain on the operator even a trained operator would usually need some relief after about 15 to 20 minutes of constant use assuming that they were in a pretty good state to start with because of the stereoscopic system relying on the brain and some quick fingers to do most of the hard work it was somewhat faster to use straight out the starting gate compared to a coincidence rangefinder assuming equal competence of operators but it would suffer deterioration in accuracy much quicker as the operator wore out it was also somewhat more vulnerable to distractions that might automatically draw the operators attention and of course needed somebody with almost perfect visual focus whereas the coincidence rangefinder could be used even by someone with fairly strong prescription glasses and once the range was established working out corrections by dial was a simple and steady process at least as long as you were targeting something like a ship so all of that meant that whatever choice of rangefinder you used you could now work or work out how far away your enemy was but that wasn't the end it wasn't him at the beginning of the end although it might be the end of the beginning of your efforts to hit the enemy it was relatively simple to mount a rangefinder on a rotational pedestal that read off angles of a circle and this could be used to give a bearing to the target relative to the ship although a separate of us could also be used to do this it was advisable to have this device mounted with and ideally atop the rangefinder if you were going to use a separate unit as if the difference in angle over a device that might only be six feet across and a larger one obviously could be much wider could give you an accurate range then placing a bearing observation unit somewhere else along a ship that was several hundred feet would give a bearing that was somewhat different to the one used in observations by the rangefinder which would thus give an inaccurate shot unless you compensated for it which added an additional and frankly unnecessary layer of complication to it all you also have to provide a second set of angles if you were taking at the data from a rangefinder separate to the guns this was sometimes known as the beta angle and this was a slight adjustment that had to be done on a per track basis to account for the range and bearing being for the rangefinder itself whereas the gun was as mentioned previously possibly a few hundred feet away and thus would need a slightly different bearing and range which fortunately could be determined manually or mechanically from a fixed set of tables as the relative position of turret and rangefinder generally didn't change again unless something had gone awfully awfully wrong and at which point range and bearing data was probably the least of your worries you could of course obviate this difference by mounting the rangefinder directly on the turret and indeed many battleships did carry these devices however the turrets were considerably lower down than somewhere like say the top of the bridge tower or the top of the main mast and mounting a rangefinder in that position was generally better because but you could see further from a higher vantage point and also it tended to be closer towards the center of rotation of the ship thus these separate and higher fire control positions would tend to be the main range finders for a ship at least until they all the main method of communication between them and the turrets was disabled now of course you might be worried that well a big vulnerable system made of delicate optics might be knocked out in battle and so you would provide additional range finders this could take the form of additional main fire control positions or perhaps secondary fire control positions that might have a similar size or perhaps slightly smaller rangefinder dotted throughout the ship and as we mentioned a lot of main battery turrets and in some cases secondary battery turrets would also carry their own range-finding systems the size of these systems was a function partially of weight because once they got to fairly substantial sizes they could weigh a fair bit and as we've covered in numerous other videos having large weights high up in the ship does bad things for your stability but also the ranges that you were actually going to operate at would to a certain extent dictate the size of range finder that you're going to use at least once the initial batch of range finders had been issued and they started to expand in size for obvious reasons if you're going to use a range finder for your main battery that's going to need to be a fairly big one because you're going to be shooting hopefully at a fairly long distance your secondary battery which unless you're the core base is out ranged by your main battery would obviously only need to shoot to a much closer distance and thus you didn't need the expense or weight of an extremely large range provided you could make do with a small one and your anti-aircraft batteries would be shooting closer in again still and so they could make do with yet again a smaller rangefinder plus of course a smaller rangefinder is lighter so you can have more of them perhaps even one per main anti-aircraft installation or multiple anti-aircraft fire control directors and being smaller and lighter you could also move them a lot faster which was fairly important when tracking a fast-moving target like an aircraft there were many different ways of doing this the Royal Navy officer using coincidence range finders the Germans in the crease marina using stereoscopic rangefinder zin World War two and various other navies using one the other or in the case of the Italians both in addition to a number of turret mounted range finders the distribution of main battery range finders can be analyzed by looking at some relatively well-known ships so for example on the bismarck class there were two secondary fire control positions with range finders one forward and one aft and there was the main fire control position also with a range finder which was atop the main mast so you actually had three albeit that the fore and aft units because of their position did not a full 360 line of view and so could only be used for the fore and aft turrets respectively but as we mentioned the Italians decided that they wanted to use both coincidence and stereoscopic rangefinder and so the Latorre o--'s are a wonderful example of just how many range finders you might find on a 1930s era warship the Latorre class in general carried a total of 24 range finders although Latura being special carried 26 in various different positions and obviously of various different sizes there were six 12 metre wide range finders located in three paired installations otherwise known as duplex installations and each of these installations contained a 12 meter base coincidence rangefinder and a 12 meter pace stereo rangefinder each of these installations was present at the back of one of the main turrets and obviously there were three turrets you also had in what's sometimes called the wedding cake fire control position atop the notorious main mast another duplex installation this with a seven point two meter base which was installed on what's basically the the center of the three tiers there was also a 7.2 meter individual stereoscopic rangefinder that was positioned on the lower of the three tiers and this one was apparently used for ranging to more general objects that the Admiral or captain wanted to have a range measured too as opposed to direct main battery gunnery which all of the other ones we've just mentioned were dedicated to in some way shape or form so with eight separate range finders all dedicated in some manner towards calculating the range for the main gun batteries it's perhaps somewhat more understandable now as to quite how the Latoya's managed to achieve very accurate straddles and ranges almost consistently throughout their time in world war ii it's just a pity the shell quality meant the version wasn't quite able to exploit the rapid and accurate ranging that they were capable of each of the triple secondary turrets on the Latoya's of which there were four had their own 6.3 meter base stereoscopic rangefinder and there were two more five meter base duplex system so that's again a coincidence and a stereoscopic system that were mounted on to fire control positions that were designed to control the secondary battery as a whole there were two more three meter based stereoscopic rangefinder Zin fire control positions for the 19 millimeter anti-aircraft guns a random three meter reserve stereoscopic rangefinder near the base of the main mast and four two meter base stereoscopic rangefinder x' that were incorporated into traversable directors for the lighter and here craft weapons Latorre o as we mentioned had two additional ones which were to meet at base stereoscopic rangefinder x' that were stuck on to one of the three meter stations in the forward part of the ship so yeah that was a lot of optics so after all that you now have the range to shoot at and the bearing to train your guns to well except not quite you see there are two other big factors that come into play one the fact everything's moving and the atmosphere the latter part at least in the 1900 to 1950 period could not be measured in any meaningful way as whilst local air temperature pressure moisture levels wind direction and so forth could be read at least towards the end of the period with the relative degree of reliability the simple fact was that at any significant range these conditions might be entirely different both at the target and at various points in between the shell would also travel high into the air on a ballistic arc before descending and conditions at different altitudes would also affect the trajectory somewhat you also had to accommodate for the curvature of the earth and all of this meant that for even two completely static targets between these factors and various slight inaccuracies in calibration and manufacture of the fire control systems the chances of a first-round hit were basically nil and so Corrections would be required after the first salvo although how much any given shell was affected by these atmospheric conditions would vary significantly depending on the gun and shell profile in terms of speed mass and angle a high velocity 15-inch shell coming in a shallow angle for example would be much less affected than a low velocity and obviously lighter 11 inch shell that was traveling through a much higher arc so whilst at least in the classic battleship period you could only partially compensate for the atmosphere and the moving around part and that could be compensated for to a much greater degree and this would however require these services of a fire control system that included a central fire director and a fire control computer the reason for the central fire director was simple with the first salvo pretty much guaranteed to miss you needed enough shots landing to give a rough idea of where your point of aim had actually been relative to the actual location of the target one shell was not enough variations in the gun the shell the charge or any other number of factors including the atmosphere might cause it to go long short or wide of the aim point and you'd have no way of knowing two shells was almost as bad as even if one of them was on target for your actual aim point which of course there was no guarantee of because both of them could be completely off kilter and you'd have no way of telling which one was on target even if there was one three was better as the chances of two out of three shots being dramatically off were low but it was still possible for was considered ideal for the period in question for the most part since a single rogue value would be obvious against the three that were on target and even if two of them were out that they would probably be out by different amounts so that would allow at least the other two that were on target to be measured against in the worst case if you're four shots went completely all over the place on early dreadnaughts that had eight to ten gun broadsides that still left another half salvo available to try again or a couple more tries if you happened to have a ship with a twelve gun broadside alternatively in these high barrel count vessels you could fire a half salvo with more guns in that particular case six to give more data points than there's less chance of rogue values throwing a data out the director also enabled you in theory to aim all the guns you wanted at the same point and fire them at the same time whether this was completely remotely or by providing a single common set of data to all guns for them to follow manually or some hybrid in-between this was important to ensure that the same set of circumstances was affecting all the various shells in the particular salvo war half salvo as whilst ripple firing the guns it looks very impressive of course the exact location speed position and temperature and atmospheric conditions surrounding the ship would vary on a second-by-second basis and so a ripple fire masae looks spectacular not tremendously useful for actually working out if you're going to hit the target or not the fire control computer meanwhile was the hub that tied all the information that was being gathered together and would pass on a final set of ranges elevations and bearings to the guns this was not a computer as you might understand it now these devices were initially purely mechanical and later on electro-mechanical as opposed to electronic that is all the calculations were done by systems of gears levers shafts and alarm and manner of interesting clockwork and the electrical part was generally there just to provide the motive power the reason that you needed these devices was that whilst any single individual given calculation for the various factors you had to account for might be relatively quick and easy to solve doing so for each and every calculation that needed to be done it would take a whole room of people long enough that the output would be useless by the time they finished it and they need to start over again especially as many calculations either needed the input of others to be worked out or were mutually dependent on each other to give a final result a fire-control computer meanwhile could do all of this for you almost instantly and the better ones could to varying degrees also update themselves on the basis of the initial entered values which saves some time when it came to working out the fire control information for the next salvo so what factors did these mechanisms need to account for and why well let's briefly go over a non exhaustive list some of these factors would have their own instrumentation such as in klonoa ters to gather the relevant data to feed in and also note that some early systems were not capable of either accounting for or at least accurately accounting for some of these factors the in part because of limitations of the device itself and in part because of limitations of instrumentation both of which would continue to advance through the first half of the 20th century first and there was your speed and this needs to be factored in because anything on the ship including the shells would be moving forward at the speed of the ship and thus a shell fired at a target would if it was aimed theoretically true actually land slightly ahead of the aim point because it would have a bit of horizontal momentum this would need to be factored against enemy speed to produce an overall speed difference which would then give a final correction to the guns which would bear them slightly ahead or slightly behind the initial aim point established by the range finders depending on the relative speeds of the two vessels second your relative course this was not dependent strictly on your alignment to north although this come into play in another factor that we'll talk about later but it was largely concerned with the effect of your course relative again to the guns themselves as if your guns were pointed at 90 degrees to one side or the other and you were going in a straight line this is effectively the same as calculating for factor one your speed but if you are sailing away from the target you would be importing a slight negative velocity to the shells which would then make them fall slightly short without correction the opposite held true if you were closing with of the target and these relative changes in velocity were dependent on input one of speed as the relative angular and forward velocity factors were dependent on the overall speed of your ship and again the enemies course relative to you would also be a factor isn't right angle triangle trigonometry fun third your rate of turn this was important obviously as turning meant that your course and possibly speed would be constantly changing as well as adding inertia to your shells as they and the rest of the ship would generally try and keep going the way that you you they had been previously if you were turning the turrets would also have to turn at a certain rate relative to your speed of turn in order to keep the guns trained at whatever points you were aiming at and so all of this would also induce various changes to the aim point fourth roll the ship would normally be rolling to some degree and of course a gun aimed a certain angle would find this absolute angle changing with the roll there were a couple of ways of dealing with this later on you could have a powered system that used gyros and motors to keep the guns at the same a relative angle to the horizontal you could keep the guns at a fixed angle and measure the ship's angle as it rolled which was more the case in earlier parts of the 20th century in this case you would configure the guns actual aiming angle to account for your goal and again there are several ways of doing this you could calculate the overall upwards or downwards velocity imparted during a roll and for the guns mid-roll with a corrected aim angle to account for this oh you could wait until the ship reaches the apex or nadir of its role when the shells would in theory have a neutral velocity caused by the roll assuming of course that you could react fast enough to fire at that particular point of course due to that being there's a the apex or an idea of the role you'd have to adjust the angle commensurately or you could simply set an acceptable amount of roll induced velocity and set the guns to fire only when the speed due to roll dropped below this regardless of where in the roll this actually was and of course these various methods sit on a sliding scale of precision versus actually allowing you to fire more than once in a blue moon number five is pitch like roll of this imposed changes to the velocity of the shells as the ship rose and fell and more so than roll he could also impose changes in height over the guns which could of course make a shell go short or long or left or right if the ship's course was significantly off parallel with the target this one was more of a catch-22 as compensating at the top or bottom of a pitch has the most neutral relative velocity change to the shell but the biggest change in height and compensating for the middle of a pitch has the least change in height but the most change in velocity to account for note that in this case a best fit calculation it may need to be made since obviously the ships pitching is going to be affecting different turrets in a different ways at the same time at number six we have temperature this is both of the gun and of the air where you can measure these for the gun this affects the tendency of the gun to droop it also slightly affects the burn rate of the charge and thus the amount of energy imparted to the shell the grip that the gun exerts on the shell and other factors because obviously the metal of the gun will very slightly expand as it gets warmer and for air temperature this affects both the initial starting temperature of the gun as a gun that's been sitting quite happily baking in the equatorial Pacific is going to be significantly warmer on first shot than a gun which you've just chipped a bunch of ice off because you're running in the middle of an Arctic convoy and there are other factors associated with air temperature such as air density and updrafts extremes can also affect the overall size of the gun and shell slightly so again if you are in the middle of a Pacific summer on the equator your shell and your gun are going to have expanded very slightly which will lead to a slightly tighter fit whereas if you're on the artic convoy duty both gun and shell have contracted minutely which will mean that the fit is slightly looser and that's a bit of a catch-22 because well the shell will move up the gun slightly more easily but at the same time it does open up the possibility of a very slight breaches in the seal um which obviously there are other physical factors to take into account in that like the driving band on the shells but that's a completely separate system we won't go into here but suffice to say whilst these expansions and contractions might seem miniscule to the naked eye when you're shooting a target that's potentially a dozen plus miles away it can make a fair bit of a difference at number seven there's moisture levels moist air obviously is slightly denser than dry air at least as far as the shell is concerned because it's hitting a bunch of water molecules and so a shell that's fired in a very damp atmosphere will travel fractionally shorter over distance than an identical shell fired in a very dry air again this change may only be slight but when in terms of distance assuming you're shooting a broadside target your target depth might be one five hundredths to one one thousandth of the distance that your shell is actually covering even these small factors can very quickly to throw your aim out because let's face it you only have to miss by a fraction of a meter and you've missed naval gunnery rarely gives medals for almost number eight is overall air pressure that air pressure will of course offer more resistance or less resistance and depending on its relative level but and again this can introduce small errors overall and all of these factors whilst to a degree they can depend on each other they can also run on completely separate lines so you can have cold dry low-pressure air or you can have hot moist high-pressure air or any variable therein you also have to account for number nine wind speed and bearing this is actually quite a big one as it can affect all aspects of a shells flight a headwind obviously will drop the range of a shell a tailwind will increase it a sideways wind will force the shell off course and a wind on anything other than those four 90-degree points will impart aspects of all of these effects to a shell with all these environmental factors that we mentioned earlier they can also vary at different points and altitudes along shells course the wind might be twenty knots easterly where you are it might be ten knots westerly where the target is and it might be 20 knots northerly a mile up into the atmosphere where your shells going to be passing and so without much more recent technology it was only really possible to adjust for values that could actually be measured from the ship itself I your local environment and maybe some of them were obviously visible ones that were around elsewhere for example if you had low cover scudding clout for instance or your range finders could see that perhaps the flags on your target vessel were pointing in a slightly different bearing and with passes that somewhat less or more energy compared to your own coming in at number 10 was the enemy's speed now you had to lead your shop as if you fired we're a moving enemy was at the time of firing then in the 20 or 40 seconds it took the shell to arrive at typical battle ranges they're not gonna be there anymore so working out how fast they're going and thus where they would be almost a minute into the future assuming they don't change course was pretty important this of course also played into the relative speed between the two ships that we discussed all the way back at the beginning of this list number 11 and the enemy's course and bearing and again this informs the relative change in distance between the ships and the absolute change of location for the target a closing target obviously see a shell aimed at their previous location go long even if you correct it for speed and vice versa so this will needed to be adjusted for as well and like enemy speed this would also inform a relative change in position between the ships since this may cancel out or exacerbate the differences depending on the two sets of data and number 12 the enemy's rate of turn this would inform how the previous two points would change on a moment-by-moment basis as well as take into account the targets speed to produce a likely point location for the target in the future that was basically just additional linear extrapolation for extra complexity all three of these last factors would of course interact with the same factors that were aboard your own ship as we mentioned and this would create an ever varying correction to your aim point it should be noted that taking to account all three of these for your own ship and for the enemy's ship and giving a sensible result was something only the later fire control systems were capable of doing and number thirteen the Earth's rotation shells travel over a long enough distance in naval gunfights and spend enough time in the air to require an accounting for the fact that the earth and anything that's more directly bound to it like say oceans and ships will have a she moved on slightly by the time the shell comes now you need to use these ships latitude because then you can compensate for the relative speed of the earth at your location but you also need to account for your course relative to true north I remember we mentioned that right up at the beginning because whether the Earth's rotation would throw your shells long short or side to side was dependent too on their relative angle to the direction of Earth's rotation so all of these Corrections would be fed where possible as I said given the limitations of the instruments available and the fire-control computer into a final corrected dataset that would be sent to the guns once the first shells were sent out observations about where they had landed compared to where they'd been expected to land would be fed in along with any updates to all of the above factors that might have come in since the guns were fired and a new position was calculated another next salvo or half salvo would go out and hopefully you'd land your shells a little bit closer and so on and so on until hopefully you hit something now there were ways of speeding up the process for example if you fired two half salvos one above and one slightly below what you thought the given data actually said this would give a fast idea of where the errors lay because I say you probably not expect the tachi hit with your first aim point alternatively you could go with what we called ladder shots in which you would walk a number of small shells elbows along a series of ranges again to try and get at least one close to the target at which point a faster and hopefully more accurate fire could be opened to maximize hits in minimized time now early systems were relatively slow in some cases hand cranked and could only utilize a limited number of the previously mentioned inputs for example some systems would give you a prediction but you'd have to input all the settings again to get a new prediction whilst more modern units could keep a running track that you could update on the fly likewise many early units could only work with direct linear motion if your ship or the enemy's ship changed course you'd have to start the calculations over with your new vector data as time went on electric power was introduced more systems allowing more advanced calculations as well as new instruments providing new data and of course more processing power radar of course would eventually offer extremely accurate course bearing and range data and assuming it was working and calibrated well as well as giving constant updates on what the enemy was doing the history of the exact mechanics of some of these systems such as the drea table the mark 1 fire control system the Admiralty fire control table and the like will all be looked at in more detail at another time but suffice to say that whilst at the start of World War 1 something as simple as the enemy turning away would mean you had to reset the entire system and start over from scratch by the end of World War 2 the most advanced systems theoretically would allow you to be doing a figure of 8 in your battleship and still maintain a reasonable fire control lock the entire time obviously the exact location and level of protection afforded to these delicate fire control instruments was somewhat important when it came to ship design you needed quite a large number of crew to run them and well with the best will in the world they're pretty delicate instruments they don't react well to heavy shell fire well humans don't react very well to heavy shell fire either so double reason to protect them but of course again and for higher up in the ship they were the more weight this would add and putting on even more protection to them would just increase weight and decrease stability even further and so the fire control systems were relatively vulnerable even if you could take the actual fire control computer and put it somewhere relatively protected it relied on inputs from various delicate instruments and these couldn't be protected to a relatively large degree for example with your range finders you physically need those lenses to be able to see you can the rest of it in some kind of arm that box as indeed would be done with the rear-mounted rangefinders on turrets but at the end of the day if a splinter smashes that lens in that prism it's a thing that of action and you can't really protect it that well against that kind of fire so this is why redundancy was very much a thing as we talk with the Latour EO class and this extended to the fire control director systems and fire control computers as well so we've already seen with this mark that they had a primary and two secondary systems and with other ships such as say of Vanguard there could even be cases where the entire main fire control system was entirely duplicated so you could smash away one of them entirely and the other one would just take over as if nothing had happened and of course at the end of the day if all of those systems were either destroyed all the methods of communications between them and the turrets were cut the turrets had their own range finders and in some cases would have smaller versions of these kinds of fire control systems that wouldn't allow them in turn to calculate some of this data but the lesser nature of these systems would of course mean less accurate fire and they could only generally be used for the turret that they were particularly associated with which is why again for example at the final battle of the Bismarck once the primary fire control system has been knocked out the Bismarck's accuracy of gun fire slackens and then once the fore and aft control stations have also been demolished the turrets operating under local control have a pretty poor chance of hitting anything now none of this of course addresses anti-aircraft fire control systems which have their own set of issues to deal with because it's a much more 3d environment and you also have to be by design in much more exposed positions with a lot greater free range of 3d movement so at some point in the far distant future I guess we'll address anti-aircraft of our control systems but for the moment although this has taken about an hour I hope this provides a certain degree of clarity as to just how complex it actually is to take a shell on one warship and lob it across the ocean to ideally intersect with an enemy warship several dozen miles away so with that we'll wrap up here thank you very much for listening and hope to see you again in another video that's it for this video thanks for watching if you have a comment or suggestion for a ship to review let us know in the comments below don't forget to comment on the pinned post for drydock questions

Channel: Drachinifel

Views: 474,058

Rating: 4.9091063 out of 5

Keywords: wows, world of warships, Range finding, plotting, naval firce control, fire control director, Coincidence rangefinder, Stereoscopic Rangefinder

Id: cbXyAzGtIX8

Length: 58min 49sec (3529 seconds)

Published: Wed May 27 2020