[Music] [Music] hello everybody and welcome to the forward plotting room aboard USS New Jersey she's currently in dry do and some of you have seen the video I did on Fire Control Systems generally but we're now going to look at Fire Control Systems in particular the one on USS New Jersey and that one that's near enough with a few minor differences common to all us fast battleships and other major warships of the second world war now to do that we have with us a man who has probably forgotten more about us Fire Control than most of the rest of us will ever know Dr John skulls uh so if you'd like to give us a little bit more information about yourself please go ahead hi I am Dr John skols uh many people think I served in the Navy but unfortunately I never really had the privilege uh however I have had the privilege of being a supporter and volunteer on a number of historic naval ship ships particularly USS Massachusetts and USS Salem for over 30 years I've actually been studying Navy ships and Naval History since I was about eight or nine years old at that time I lived in Hampton Virginia which is directly across Hampton Roads from the main Atlantic Fleet operating base in N Virginia so while other kids uh did Cowboys and Indians and fire engines Hydro battleships and cruisers and aircraft carriers and destroyers my special interest in terms of ships is in the big gunships battleships and cruisers and particularly the aspect of Naval Gunnery and that includes both the Armament itself and the systems that control it I am what is called a battleship nut I had the uh privilege of uh giving uh Firepower tours on board the USS Massachusetts as well as a number of other tours uh on the Salem and the Massachusetts uh and have been able to work with a man who actually fired 16-inch guns a Gunners mate Tom lowney uh who was on the USS Wisconsin uh I've also been very helped in my studies uh by Chris nardy the curator and now director of the USS uh Massachusetts and Battleship Cove for giving me uh ordinance Publications on the Mark 38 director and Associated Fire Control equipment as well as the Gunnery doctrine of the USS Massachusetts in 1945 which explains how they actually used the guns now the 16-in guns of course are the reason that the fast battleships of World War II US Navy were built everything on the ship is there to support the guns the armor is there to protect them from the effects of enemy fire the engines are to move those guns to where they are supposed to be to do what they need to do the crews are there to operate and maintain them and uh the support facilities are to feed and supply those crew members as well as all the components of the ship needs to operate while they're immensely powerful and effective weapons they can only be so if they're able to hit what they're supposed to hit they need to do this in order to do their job and the job of getting them to hit what they need to hit is the job of the Fire Control System [Music] now when the Massachusetts and the other fast battleships and the New Jersey were built their primary targets were anticipated to be enemy battleships and other large vessels at Sea however the problem of hitting a moving ship however large it is or other large vessel at Sea from another moving ship especially at a great distance as much as 21 miles for the 16in 45 caliber gun as much as 24 mil for the 16in 50 caliber gun uh is anything but easy and straightforward it's a mathematical and Technical problem of mindboggling complexity involving over two dozen variables most of those variables are continuously changing usually they're changing at variable rates and the rates at which the variables are changing are also [Music] varying and most of these variables also affect other variables and cause a difference in the rate at which they change as well even though a battleship is a relatively stable platform for a ship in a Seaway particularly uh when the seas are are rough the ship is rolling pitching and yawing continuously it's also moving along its intended course up to 27 knots for the North Carolina South Dakota class up to 33 knots for the Iowa class to give you an idea of how difficult it is to hit a moving Target from another moving platform imagine this analogy you're in a car and you're driving along a rough bumpy twisting winding Country Road doing 30 m an hour which is about 27 knots now imagine another car on another similar Country Road roughly parallel to the road you're on which is also going about 30 m hour and that road is some distance from you but the simplest problem will make that car essentially directly across from [Music] you at a 90° angle you have a pistol in your car and you're the good guy the other car is full of bad guys so you want to stick your pistol out the window of the car and see if you could hit the other car [Music] far now if that distance was very very short say about 20 ft you might have a chance of hitting it even though your pistol's going to be doing this you might get lucky however if you make that distance 10 times longer at 20000 ft or something just short of 70 yards it becomes extreme ly difficult now make it 100 times longer at 2,000 ft which is a nautical mile and it becomes essentially impossible you could never do it even if your pistol could shoot that [Music] far but a battleship you say well that's a much bigger Target than a car a car is uh say about 15 ft long and to take the shortest of the fast battleship to Massachusetts it's about 45 times longer than that so we could multiply that 20 ft by 45 and get 900 ft or 300 yard at 300 yard you might be able to hit something as big as a battleship again with your pistol out the window but if you raise that distance to 100 times more more then 200 ft becomes 9,000 ft or 3,000 yards and you're already well beyond the distance where your pistol could shoot but you're approximately at the distance at which a single gun laid by a single gun layer through a telescopic site using the continuous Aim Fire control methods of admiral Scott and in the Royal Navy and Admiral Sims in the US Navy could actually have a fair chance of hitting the Target and that's about the maximum range you do it now multiply that by 10 again and now you're out to 90,000 ft or 30,000 yards or 15 nautical miles or about 17 land miles at which his hitting with an individual gun laid by an individual layer is essentially [Music] impossible yet this is [Music] the distance at which the modern fast battleships were expected to be able to hit a moving enemy Battleship Target and the scenario I have described to you is actually the easiest possible scenario because the rates of change of range and bearing are very very small almost zero so that's the easiest now imagine that you turn the cars around in Direction and One car is going 30 m an hour in One Direction and 30 in the other so the relative speeds of the cars is now 60 M an hour which is about 52 knots imagine what it would be like with your pistol yet again the fast battleships were designed to be able to hit other ships at a great distance even in that kind of scenario with a very rapidly CH changing range rate and bearing rate and we'll give you some examples at the end of how this actually was accomplished during World War II by us fast Battleship now all of this was achieved by The Mark 38 gunfire control system with the Mark 38 gun director most people when they think of the Mark 38 gun director they think of the structure with the rangefinder up at the top of spot one and at the top of spot two the after Fire Control but that's really only only one component of the fire control system that system includes that director but also the other included components including the Mark 8 range keeper essentially a mechanical analog computer the Mark 41 or in the case of South Dakota class Mark 43 stable vertical it also entails the development of electromechanical precision motor controllers amplid and receiver Regulators to be able to move structures including guns and turrets and also directors under Precision remote control from the computer it relies on reliable accurate electrical transmission of data so so that you don't have to call down for example the bearing of the target through a voice tube have somebody hear it and then try to crank it in to a computer and maybe mishar it or the delay in time that it takes to get it in there can cause errors in the Fire Control [Music] System uh and then late in World War later in World War II ever more advanced Radars including the most advanced the mark 13 Fire Control radar and the first Precision Fire Control radar which was accurate in both range and bearing the Mark 8 and its modification the mod 3 which was an improvement the system also relies on the search Radars to pick up the target initially and to provide an initial course and speed and once Radars were able to do this that was a big help to the Fire Control uh system in order to get an accurate initial solution so that even your first Salvo might well be on target even at long range and together this Fire Control System achieved what was probably the best solution to the surface main battery Fire Control problem that was sought by many other nations but probably the US achieved the best solution during World War II and the postwar years this was a mathematical and Engineering accomplishment of mathematical Geniuses and engineers and it still causes amazement by people who study the history of computing and design modern digital electronic computers now the Mark 38 director and fire control system has four main components and each one of those is primarily concerned with one part of the Fire Control problem and solution but all of them are interconnected the Mark 38 director that's the visible structure again at the top of the forward or spot one uh Tower and after or spot two after Fire Control Towers is the director proper and is primarily concerned with establishing the range and bearing and following them excuse me the range and bearing of the target and following them to track the target this provides data input to the system and also by means of a feedback control Loop it provides correction to the computer output solution resulting in an accuracy that was probably achieved by no other system of its era we'll see the director itself a little later in this video now the heart or the brain of the fire control system is located in the main battery plotting rooms on the Iowa class there are two a forward one and after one each one containing all the necessary components uh to do the calculation and also as we'll see a little bit later the stabilization uh on the South Dakota and North Carolina classes there is only one main battery plotting room and it contains two Mark 8 rangee Keepers or computers and they're Associated stable [Music] verticals this rangee keeper is located of course in the main battery plotting room which is protected by the ship's main armor the most protected part of the ship it's contains the predictor component of the system to calculate the course speed and position of the target at the present time but also at both the present time and at any future time on a continuous basis and it takes this information about the target position and applies all the necessary ballistic calculations to aim the guns at the proper point where the shells where the target will be when the shells arrive in the future the predictor function is performed by The mar8 rangee Keeper often called a computer built by the Ford instrument company and no that's not Henry Ford the automobile manufacturer it's Hannibal form Ford a mathematical and Engineering genius unlike modern digital computers this is a mechanical and electromechanical analog computer it uses shafts gears cams differentials and electric motors to solve only one mathematical problem although as we've seen this is an incredibly complex mathematical problem each model or mod of the Mark 8 computer was designed only for one not only for one gun but also for only for one ship or ship class if every ship in that ship class were identical to make it calculations accurate enough to be useful at Great ranges its components need to be manufactured to incredibly tight tolerances down to less than 110,000 of an inch and in fact uh some of the specifications require that the tolerances be at 70° fah because metal expands and contracts with temperature when the mar8 rangee keeper was designed in the late 1930s it was the most powerful computer in the world but it's precise as it was it was also incredibly rugged it's a box that weighs about 3,000 pounds and it was rugged enough to withstand the shock of 16-in gunfire including full nine gun Salos which shake the ship up considerably when the guns are fired when the Iowa class was reactivated in the 1980s the Mark 8 computer uh was retained because at that time digital electronic computers could not withstand the shock of the 16-in guns firing the marade which has a different mod for each ship contains most of the controlling Computing and transmitting mechanisms of the Fire Control System despite the name it's more than just a rangee keeper it keeps and predicts future range continuously but also it's a bearing keeper keeping and predicting Target bearing at present time and in the future it's a deck tilt computer meaning it senses the tilt of the deck and the tilt of the turrets which affects the Fire Control solution and it also is a trunion tilt collector which again when the guns are elevated the turret turns like this it affects the accuracy of the Fire Control System it also runs a graphic plotter and it computes indicates and transmits electrically information to point the guns at the Target set the sights and to train an Elevate the guns continuously and to compute and Signal the time of flight of the shells its outputs include Corrections for drift these are spinning projectiles and for example like a curve ball that spin will cause a clockwise rotating projectile to drift to the right it corrects for variations in initial velocity depending on the wear of the guns and the type of powder charge Chosen and the type of shell chosen it corrects for the movement of our own ship and the movement of the target analyzing both separately and then combining them to get the range and bearing to the target from our own ship it corrects from trunion trip from a uh horizontal plane and director tilt also because it also can stabilize the director which is necessary to get accurate bearings and ranges uh on a distant Target uh the graphic plotter also plots present range Advanced range and sight deflection electrical inputs or data into the markate rangee keeper include our own ship's course that's provided by gyro Compass our own ship's speed that's from a pitometer log or at very slow speeds can be put in By Hand by a conversion chart director train in automatic for automatic operation which we'll explain in a little bit Direct VOR trained indicated for local operation level which can be either continuous or selected cross level which can also be either continuously provided or selected at a particular value and then there are also mechanical inputs of data and those are continuous level and cross label and selected level and cross level from the stable vertical hand inputs that are cranked in manually for data to the market include movement of the Target that is course and speed initially of the target wind spots that is Corrections provided by a fire control officer usually by a person actually standing at the computer called The Spot coordinator generated range generated bearing initial velocity of the projectile the powder charge being used whether it is the service charge a reduced charge or in case of the Iowa class battleships there's a special charge to duplicate the ballistics of the 16-in 45 caliber [Music] gun selected train if used in other words you can select a particular train angle at which the guns will fire this is frankly rarely used and you can also input by hand any of the inputs that are normally received electrically in case the electrical transmission fails these would include the range Battle Order control order plot ready signal transmitters sight deflection and sight angle the Mark 8 outputs its information by Synchro generators which are electrical devices to trans MIT electrically numerical values which then are reproduced at the receiving end either as an indication on a dial or run through a receiver regulator to actually move physically the component that is supposed to be moved to those values for example to elevate a gun to the correct value to train a director to the right bearing [Music] and these include the gun train order in automatic mode we'll explain that in a minute the gun train order in indicating mode and you can also have a gun train order in information mode basically just to tell the gun turret this is where we're planning to train the gun it's also a gun elevation order in the automatic mode and in the indicating mode there is no uh information mode for elevation site deflection and site angle this is a necessary values to initially be set by the sight Setter in the turret generated director Train That's generated by the computer bearing correction which basically means the generated change in the director train or the essentially the rate of change of the director train deflect ction that is the bearing to the Target the amount the guns must be offset in order to lead the Target or Trail the target uh if your ship is speeding past it in the other direction the range both present range and advanced range this is there for information and also so that the guns can be set to the correct elevation and train and a parallax range function because all of its calculations are based on a single central point on the ship and that is the center of the Periscope director the mark 40 director that's in the big cylindrical conning tower all of the distances both horizontally and vertically of the gun turret and the directors must be known from that reference point and corrected for Parallax based on Range to the Target for example if the range were very close there would be a big angle between where the turd is pointing and where that reference point is pointing and that would have to be corrected for at a very long range that's a very very small angle that has to be allowed for now the type of computer that we're dealing with a Fire Control System we're dealing with is termed a synthetic system there are two basic types uh that were developed for Advanced Fire Control Systems beginning uh in the days just before World War I the first type that was developed was called an analytical system and basically what that does is it makes measurements of the line of sight to the target from your ship to the enemy ship there's a device where you can put in your estimate of the target ship's hor and speed your own ship's course and speed and by lining up the line of sight it will show you the change in position of the target with time in other words it will give you a rate this can be split into two Vector components a range component sometimes called rate along which would for example be the range is closing at 200 yards a minute that is you know the target is coming 200 yards closer to you every minute that passes and then you can also have what's called a rate across which can be a speed but that can be converted into a bearing range so for example you could have a change of bearing of 2° per minute based on this you can plot out how the enemy Target ship is moving compared to your ship as a reference point and if you do that and your ship does not change course and the enemy ship does not change course then you end up with a straight line plot mostly this was plotted in range because that was the most difficult factor to try to compute and you could tell the rate at which the range was changing by on a range time plot looking at the slope of the curve if the slope went in One Direction the target was moving away from you at a certain given rate if it went in the other direction it was closing on you at a certain given rate you could figure out what that rate is and by projecting ahead your line of plots that you had made and you've did this actually graphically in many cases use most of the systems use a graphic system one way or the other you could then project ahead oh one minute in the future that line is going to intersect this point at this range and this bearing and then you could set your guns in advance to that and then fire at that exact moment this is the type of system that was mostly used in World War I it was effective only in the situation that we talked about with the two cars going along the roads roughly parallel to each other roughly 90° angle roughly broadside it did have a corrector mechanism for the roll of the ship usually this these systems did not have a cross- level mechanism so the guns really needed to be corrected uh be pointed on the broadside so they could be corrected in level that was the only correction you had and if you look at your engagements between battleships and battle Cruisers in World War I almost all of them follow this kind of model the two lines of ships run on roughly parallel courses with maybe slight convergence or Divergence and roughly parallel to each other and the ships fire at roughly 90° angles across the synthetic system has many advantages over it what do we mean by a synthetic system well a synthetic system takes the initial range and bearing and estimated course and speed of the Target and calculates it what the Advan range that is the range in the future will be and the bearing in the future will be based on the rate of change of rate and bearing as tracked by the director so in this case if your ship changed courses this rate of change of rate will change rate of bearing will change however the computer will detect this and correct the solution for those changes and it does this on a continuous bases this allows you to maneuver it also allows you to deal with much more rapid rates of change for example this system a synthetic system can deal with two ships on opposing courses moving at very high relative rates to each other now almost every synthetic system that was designed has some sort of feedback mechanism to check to see whether this virtual Advanced range and position of the Target in range and bearing is actually accurate part of that of course can be firing the guns and seeing where the salvos land and that's one mechanism that was definit ly used but in the case of the Mark 8 there's an additional feedback loop built into the system the director not only aims the guns at the Target but it also has the director follow the Target and track the target initially the director has to track the target with the hand wheels of the pointer and the trainer the trainer particularly and he puts his crosshairs on the Target and continuously tracks it and he has a track when the computer has a solution based on that track he can be informed and he will throw a switch and turn it into automatic at that point the director now I I'm sorry the computer now drives the director through the synchros and the amplid and moves the director with no hand input at all the trainer then watches his crosshairs if he's doing it optically or fixes the Target on a radar scope right in the middle of the scope we'll show you one of the Scopes that he does this on and follows if the computer's solution is correct the crosshairs will stay right on the Target optically or the radar Position will fall follow right where he puts it and it won't drift if it starts to drift he can then take his hand wheels and move them so the crosshairs move back onto the target this will send an electrical signal down to the computer the computer will then use this to correct its solution he can then observe and now the crosshairs will stay with the target this gives a big Improvement in accuracy and allows you to have a realistic chance of having a straddle and the potential for a hit even on the very first Salvo Now by triangulation the computer takes the predicted position and therefore range bearing course and speed of the Target and gives the future Advanced range and bearing of the Target and it gives this both to the director and to the guns this feedback loop corrects the predicted position and therefore range bearing course and speed of the Target and therefore the future Advanced range and bearing of the target so the [Music] markate rangee keeper and Mark 38 director continuously computes and corrects where the target is and will be and the place that the guns have to be a to hit the target corrected for factors such as The Parallax of each turret corrected for range but now we have to correct for the moving of the ship which we remember is rolling pitching and yawing especially at the sea is rough and therefore the train and elevation to the point the guns at the correct place is constantly changing due to the motion of our own ship the correcting component of the system that corrects the solution continuously for own ship motion is the stable vertical in the South Dakota class such as the USS Massachusetts this is a Mark 43 stable vertical made by General Electric and in the North Carol inas and the Iowa it's a Mark 41 stable vertical which is made by Arma also all of the Cruisers of World War II used the Mark 41 rather than the Mark 43 the reason that they made two different types is to have two suppliers in case one of the stable verticals they were developing was not satisfactory both of the the ones that they did develop operate similarly and both of them apparently produced similar and very successful [Music] results now the purpose of this stable vertical is to designate and maintain true vertical in order to determine angles of level and cross level to correct the motion of the firing ship it's also there to fire the battery automatically at the proper point and interval and level and cross level and this this would be either selected or it could be continuously done uh provided the level and cross level were within certain limitations usually 15 to 20° of roll and about 5° of pitch so this provides a means of firing and level and cross level continuously what are the inputs to the stable vertical well if you do select a particular level or cross level let's say the ship is moving too fast and you want to say fire the guns only at the point of the Roll where the ship is directly vertical 0 degrees you can do that [Music] and you can put that input in by hand into the stable vertical stable vertical needs to own know the own ship's course from the gyro compass in order to orient its level and cross level and it also needs to know the target bearing and line of fire to orient its level and cross level it gets this from the director and from The Mark 8 range keeper this determines the line of sight outputs are continuous level and cross level and this comes out mechanically fed back into the Mark 8 rangee keeper correcting its already generated output solution in train and elevation of the guns for the movement of the ship so that they are continuously locked on the Target and they continuously move to correct for the motion of the ship or if a selected level or cross level is selected the output of the stable vertical is done electrically now what is a stable vertical what kind of a machine is it it's an electrically driven gyroscope oriented vertically or horizontally or both Within in a a liquid mercury damping pool and this is to presets the gyro back continuously into the vertical position the gyro moves within a frame with electrical pickups electromagnetic pickups that produce current when the gyro moves from its stable zero position in some direction or another either in level or cross level this magnetic field generates an electrical system which is transmitted to Mechanical outputs of the stable vertical by gears differentials Etc and it also generates a voltage which can be Amplified to drive Motors uh for example that's how the director can get level cross level from the stable vertical if it doesn't generate those values optically by itself so this stable vertical continuously knows if you will what level and cross level is without uh being able to see a horizon the way you have to do it optically and automatically corrects the computer and continuously then corrects the output of that computer to elevate and train the guns now one feature of All American warships of the World War II era but particularly the big gunships is redundancy in order to have redundancy all of the United States Navy fast battleships have two Mark 38 directors uh spot one which is forward main fire control tower and spot two on the a fire control tower two Mark 8 rangee Keepers two Mark 41 or 43 stable verticals as well as a third less capable Mark 40 director and Mark 3 computer in the South Dakotas and North Carolinas in the upper level of the conning Tower the secondary battery Mark 37 directors can be linked to the 16-inch guns in an emergency any combination of these can be linked together to control the 16-inch guns in addition there are multiple modes of operation to control the 16-in guns including automatic comma indicating and local that is manual control of turrets and director period the gunfire control system can be setup that is prepared to select linked specific directors such as spot one spot two spot 3 or secondary rangee Keepers that is computers one2 or three in the case of the South Dakotas and North Carolinas in the control station at the top level of the counting Tower stable verticals either one or two and linked to any combination of turrets all three two forward one AF or one single turret each individually or any kind of combination once the components are selected they can be operated in multiple types of fire Salvo which is firing all the available guns of the main battery at a single Target partial Salvo which is firing usually one or two turrets uh at the Target slow fire when the guns are fired the shells are allowed to Splash around the target they are observed and then a splot correction is added if they're off Target before the next Salva was fired rapid fire which once the correct range and bearing has been determined and the guns are on target basically fires the turrets as soon as one turret or two turrets depending on how you select are ready to go you don't have to wait for all three in case one is behind or continuous fire in this case all the guns fire as soon as they are loaded and and the ready switch is flipped by the gun captain in the turret to show that the gun is ready it automatically just elevates firing position as soon as it gets to the correct elevation it fires in the automatic mode there are also multiple types of control the main type of control is through the rangee keeper that is the computer and instruments in plot the fire control circuits are Through the Fire Control switchboard there is also an auxiliary mode a local mode these can be fired directly that is if the target is visible to the director indirectly using offsets to a Target that is not visible to the director in automatic mode in which case the rangee keeper drives both the director and the turrets to keep them continuously on targets and the guns may be fired as soon as they are loaded and ready and they elevate to the correct elevation turrets always training to keep them on target interestingly enough when the guns are fired the automatic mode also lowers the guns to their 5° loading angle automatically and when the ready switch is switched to ready when the gun Captain steps off platform throws the switch the guns just automatically go back to the correct elevation they can also be in fired in indicating mode that is by following the pointer in that case in the site stations on either side of the 16in gun turrets the pointer and trainer follow the directions of the follow the porter indicating system match up dials and that way they keep the guns at the correct train and elevation this is a continuous process they are continually using their training wheels and in speaking to uh Tom Lonnie the gun Captain uh from uh the Wisconsin who actually did this it's a very tiring process uh but a good crew can get very very good results with follow the pointer system uh the guns can also be fired in multiple ways they can be fired by the pointer and the director they can be fired by a master key and that can be located in multiple places most commonly when they're in automatic mode the firing key is on the stable [Music] vertical the guns can also be in continuous aim this is what happens in the automatic mode or in the indicating mode when the pointers are being followed continuously they can also be fired at select level during the rooll and select cross level if the cross level is more significant than uh the level in terms of the amount of shi motion there's also a special mode that the leveler and cross leveler can use during a severe ship motion called intermittent cranking where they uh instead of trying to keep the the hand wheels turning continuously to keep up with very severe ship motions they follow as best they can the motion and then if a the guns are going to be fired at a select level position just before they get there they will move their pointers ahead of the of the motion of the ship to get to the the data and that helps the guns catch up to the director uh do it by copying basically the same motion rarely they can be fired by also a select train in other words you can select a particular degree of training for all the turrets and fire when that train comes on as the turrets turn that's not used very much they can also be fired by the pointer telescope in the site stations in each turret again that's not commonly used all of this setup on the final uh components in the plotting room main battery and Fire Control is done through the main battery fire control switch boort now uh in the Gunnery doctrine of the Massachusetts there are a number of standard setups that are used if possible uh for the Massachusetts the preferred setup in daylight and good visibility that is the Horizon is clearly visible would be setup number one this would be director fire Collective meaning all guns in the main battery are controlled by the main battery Mark 38 director usually spot one they would be training leveling and cross leveling and firing circuits that is the master key that fires gun would also be in director one so they would be using optical level and cross level because it can be just as good if not better than the automatic stable vertical if the Horizon is clearly visible enough and you have good enough trained Personnel um The mar8 rangee Keeper normally number one would be used that's supposedly the best one and that's linked of course to the stable vertical number one that goes with that ring now in terms of night and reduced visibility they would use setup number five again this would be director fire Collective meaning all guns of the main battery were firing together director one spot one would be training the rangee keeper number one and stable vertical number one would be leveling cross- leveling and the firing circuits would be going through the stable vertical and the master key would be in plot at the stable vertical as well for the Massachusetts in this Gunnery Doctrine there are approximately 30 standard setups but there's a paragraph at the end saying that there's a potential huge number of non-standard setups that are possible in an emergency all of these are set up through the massive Bank of switches and the Fire Control switchboard and there are people who are operate who know exactly how to set those switches to get the setup the final component of the fire control system is translating the electrical output of the system system the director the rangee keeper or computer stable vertical and the setup in the Fire Control switchboard to the actual movement of the guns in elevation and the turret in train to point the guns to hit the target normally the guns are moved continuously and continuously point at the Target by one of two methods in the automatic fire mode the computer generated Gun Orders for train and elevation are sent through amplid that is amplifiers to receiver regulator units that electrically control electr hydraulic motors with feedback control to keep the guns continuously synchronized with the Gun Orders from The rangee Keeper or computer guns may be fired at any time because they're kept continuous ly On Target this increases the potential rate of fire this capability for large guns such as battleships or big Cruiser guns was exclusive to the United States Navy in World War II if the automatic mode was not possible for example the receiver Regulators were not yet fitted in the USS Massachusetts an operation torch at cassablanca the indicator fire was used in the indicator electrical sign signals from the rangee keeper for Gun Orders that is train and elevation move indicators in the trainers and pointers stations in the turrets who match the indicators with their hand wheel controls continuously this is the follow the pointer system moving the guns again occurs through electrohydraulic Motors continuously On Target so as long as the point are kept match the guns are continuously On Target this method relies on trainer and pointer and their training to keep the pointers match for accuracy in director generated train the director generates train [Music] orders to the directors to keep the director trained on target this also can be an automatic or indicating or F the pointer mode the rangee keeper also sends a site correction for a parallx to the site Setters in each turret once the initial value is set by matching pointers the system may be switched over to automatic or indicating that is follow the pointer and continuous parallx correction for range is provided to the SES and to the turret if the Motions are too great for automatic or indicating mode and that usually means more than 15° of roll per second or more than 5° a second Pitch a selected point in the roll that is selected level or pitch selected cross level can be used and this can be chosen either automatically on the stable vertical or manually on the stable vertical and the the stable verticals have hand cranks so that this they can actually follow the pointer of the stable vertical to maintain uh uh level and cross level well now that you've heard this incredibly complicated system if it sounds too complicated to work I think the best indication is actually how did it work when it was used an actual service and interestingly enough the best indications that we have about the effectiveness of this system at least in terms of firing at large ship targets basically enemy battleships both occurred in the same month November 1942 less than 10 days apart an operation torch at cablanca the USS Massachusetts uh scored a hit on a French Super Destroyer that maybe because we're still looking for the best indication and the best evidence the longest hit ever recorded on a moving vessel from another moving vessel with a gun and this uh is reported to have been over 28,000 yards but we're looking for information in the ship's records to see if we can't confirm and prove that if that's not the longest we may have to concede to the warit or to the chor or gy now uh for that one but let's hope that the Massachusetts doesn't uh us Massachusetts also hit the stationary French Battleship Jean Bart at about 25,000 yards and she hit her five times and that silenced and partially sunk the Jean Bart a hit in the secondary battery magazine of the Jean Bart which fortunately for the Jean Bart was empty might very very well have sunk or crippled the jeart had that magazine been filled as it turned out one of the hits did manage to penetrate all the way through 150 mm Armor Deck blow up and the ship's Rudder post and ruter stock and uh disable the rudder and also cause flooding by the stern which caused the ship to ground however cablanca Harbor was very shallow so the ship only sank a few feet by the stern these results occurred even though the USS Massachusetts had to use the indicator rather than the preferred automatic mode of Fire Control because her receiver Regulators had not been fitted she was rushed to be the fragship of Operation Torch and those receiver Regulators were only fitted later also her radar in that situation was the earlier Mark III radar which only gave accurate results in range and even those results were not nearly as accurate as later main battery Fire Control uh Radars um The Mark III radar could not accurately control fire in bearing and also the jeart was adjacent to a pier with multiple other ships there and therefore did not give a very distinct radar return in other words not a sharp blip so she was not a great radar Target for either ranging or full Radar Fire Control so most of the control all of the control in train was really done optically and some of the ranging control was actually done optically as well uh in the second uh example in the second naval battle of waddle Canal USS Washington equipped with the same Mark 38 director the same Mark 8 rangee keeper Mark f 41 stable vertical instead of the Mark 43 in the Massachusetts and Mark II radar hit the Japanese battleship kishima at night at an average range of about 8,500 yards with 20 or more 16in shells out of approximately 75 that were fired that's a 27% hit rate and if you see the hit rates that occurred in battles like judin or pretty much any other surface engagement between battleships 27% is a phenomenal hit rate now if you read uh many books they say that nine out of 75 shells uh overly hit John Bart but the larger number of hits was actually confirmed by Robert Ballard's uh exploration and photos of the Kisha and a gentle by the name of Robert lungren did a very careful analysis of all of the ship's logs position reports Etc and also uh there was a gentleman who uh met the kisha's actual damage control officer before he passed away and he knew far more about the damage uh that the ship had suffered rather than the original report of 9 of 75 which was given by a non damage control uh special now you may say well 8,500 yards boy that's close range for Battleship however if you remember that the two ships those two cars on the road when they were going parallel to each other is the easiest situation in this case the kishan was steaming at about 27 knots on an almost reciprocal course from the Washington that was steaming at 26 knots that's a find relative speed of about 53 knots per approximately 60 M an hour so the ships are going like this that is situation with very rapid changes in the rate of bearing and the rate of range change many other Fire Control Systems could not cope with that kind of very very rapid uh change but the Mark 38 director Mark 8 computer stable vertical did the job now interestingly enough this system has also provided the ability to do a number of other things with similar types of problems we don't have Battleship versus Battleship gunfire control problems anymore but the systems that were utilized in solving the naval Fire Control problem found applications in other military and non-military situations for example the stabilization and Fire Control System of the gun in the M M1 Abrams tank has a system that's basically based on the same principles as this Naval Fire Control System that was designed in the late 1930s and the one in the ABS as I understand works very very well just like the one in the battleship works very very well another example in a non-military application was in the moon moon landing now in order to get the uh lunar lander out of lunar orbit down to the moon the Retro Rockets had to be fired at exactly the right spot first to insert it into orbit and and then to get it out of orbit down to the surface of the Moon they also had to be fired for exactly the right amount of time and this is being done from a moving platform now the calculations that are involved in this are basically exactly the same calculations that are involved in a naval Fire Control problem to a Target spot from a moving Target trying to hit that um however in the 1960s a computer like this was way too heavy and way too big to fit in a spacecraft so the computation had to be done remotely that meant the information on the position of the lunar lander which was done by reference to a fixed reference a star had to be transmitted down to Houston the computations done and then sent back by radio to the lunar landing and then applied in order to fire those retro rockets at exactly the right spot for exactly the right time and as we all know the moon landing was successful had we not been able to figure out how to solve the naval Fire Control problem I don't think we'd have been able to figure out how to solve that problem problem cuz mathematically it's basically the same [Music] problem uh what are sources that you could get more information about Naval Fire Control uh one thing is through videos and I would recommend ones by dra NFL I would recommend uh the inside the history videos on Naval Fire Control that's saw on the battleship Cod website uh there are also US Navy training films that are incredibly good in explaining this information in a form that's readily understandable they are a brilliant example of teaching uh among those are main battery Fire Control procedures and basic mechanisms of Fire Control computers and there's it that's in two parts one and to there are also a number of books uh probably the best one and the one that I rely on most is Naval Firepower by Norman fredman which gives you the history and development of these systems and also a great deal of information about uh both the Us and other nations systems so that you can compare them in what they're able to do there's also a very very good website uh that Jean slow over US Navy site which has many of the ordinance Publications on these uh systems and the actual material uh and it also has training and operating manuals for these systems very very uh excellent and very informative uh system lastly if you'd like to see this for yourself I would recommend you coming to a memorial ship the New Jersey the Massachusetts the USS Salem or any of the preserved US Navy uh battleships will show you uh these systems the Texas will have a much earlier and more primitive system uh all the fast battleships all have basically the same systems awesome thank you very much oh you're welcome let's have a bit more of a look at these bits of Machinery yes 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 pin post for dry do questions