Pinned post for Q&A :)

I made my nephew an optical rangefinder as a way of teaching him trigonometry. We pretended we were working out the range of enemy ships, he still thinks it was the best maths lessons he ever had.

Before this video: how did these navy guys manage to shoot at eachother so much and miss so often? After this video: wow it's a miracle any shell ever hit the target

This is why the FCO says, "I have a firing solution." They were _literally_ solving a trigonometry problem. Those Ford Mk.I computers are a pure marvel of mechanical engineering. Just absolutely amazing.

"Genetic hybridization with a hammerhead shark is... frowned upon." Someone needs to make a compilation of these jokes, they are gold!

This talk is one of the best discussions on this topic I have ever heard. After 41 years of work on such systems for the US Navy (both guided missile and gun systems), I have A LOT of knowledge about this and this instructor HAS NAILED IT!!! This instructor is WAY, WAY, WAY better at such discussions than most other people I have ever heard. THANK YOU, DRACHINIFEL!!!!!!!

You gotta feel sorry for the Italian designer who jammed the Littorio full of the best rangefinding and fire control equipment he could build, only for the shell manufacturers to render all his work pointless. Teamwork: Ensuring your hard work can always be ruined by someone else.

Great presentation. My grandmother was a "computer" in WWII. She was one of the women that made the pre calculated tables. She later worked as a math teacher. I must say it was hell growing up having to explain to her that I was terrible at math and didn't even like it. However, it is cool that she had an important job in WWII. The computers were highly respected.

Some more "fun" things" (1) When several ships were firing at a single target, you had a MAJOR problem of figuring out whose shells were landing where so that you could adjust your guns' aim point. This started to be a problem in WWI battles when director/computer control of all of the guns became the rule. (This was before radar eventually helped show your shells in flight and thus the ability to see which ones were yours from the fire-control radar operator, if he was good.) The US, France, and Japan after WWI decided to try to fix this problem, though interestingly, the British and Germans did not (to my knowledge). The thing to do was to give each ship's shells some way of making their hit at the target area different enough to, at least in good visibility and during daylight, allow the spotters with their telescopes to sort out what to report to the fire-control personnel to adjust the gun calculations on the computer. The method was colored dye in the shell windscreen (the sheet-metal hollow false nose of the shell to make it more streamlined without compromising the usually-much blunter projectile nose and, if fitted, armor-penetrating (AP) cap on the actual shell nose). The US system had a simple paper bag full of a colored powdered dye, each ship in a group using its own color powder, and some spot-welded-over holes in the windscreen to let the water on impact slam through the windscreen interior to color the water-impact splash -- it did not work at night or in low visibility or, unfortunately, if a direct hit on the target occurred (kind of a bummer, that last fact!). The Japanese, in their post-1931 major caliber gun (6.1" (155mm) and up) Type 91 and later Type 1 AP shells, was effectively identical, but had the entire windscreen tear off the nose on water (or any other) impact to allow the now-flat-faced shell to travel underwater nose-first for a long distance in the hope of hitting the enemy warship well below the waterline if the shell hit short of the target, so it acted like a tiny torpedo on such hits (they also made the shell fuze delay extremely long to help this, which caused some problems with hitting thin armor on an actual target direct hit, a negative aspect of this shell design). The French, as they usually did, went to a more elaborate and "elegant" solution for their new 33cm (13") and 38cm (14.96") battleship guns: The dye bag was increased in size and supported by a framework near the tip of the windscreen; the windscreen was enlarged -- making these the most streamlined shells used in any warship gun ever, to my knowledge -- and a strong base was crimped/screwed to the face of the shell's AP cap to rigidly support it; and, uniquely, the tip of the nose of the windscreen had the instantaneous nose fuze and booster charge of their high explosive (HE) shells used for shore bombardment and shooting at small, unarmored enemy ships. On impact with anything whatsoever, the nose fuze would go off, making a colored flash and large puff of smoke, visible at night and even in some low-visibility conditions and, the best point, on a direct hit, too. More expensive and making the shell have to be handled with care due to the exposed nose fuze (as did any HE shell, though), but it solved all of the problems. When the British got some French naval material from refugee warships after the fall of France in 1940, they decided that the French design of this was good enough to add to their battleship AP ammo -- they had had some problems when their cruisers were firing at the German "Pocket Battleship" ADMIRAL GRAF SPEE in 1940 due to this shell-sorting problem -- and they thus created their "K" AP shells with this kind of nose-fuzed dye bag to their new and refitted AP shells, though they did not change the windscreen shape so that the shells kept their old ballistics. Germany, probably due to having so few warships, never used this dye bag option. (2) At the start of WWII most ships used the "follow the pointer" system to aim their guns, where personnel in the turret would manually adjust their traverse and elevation controls of the mount using a pointer dial set by the calculator (either the central ship calculator in normal control or some backup in-turret calculator using its own inputs in local control); he did not usually see the target he was shooting at himself. Just prior to and during WWII, the US and Germany and, eventually, Britain, developed their own forms of what the US Navy called "Remote Power Control" (RPC), where the calculated values were amplified reliably enough to directly be input into the controls and the human controllers became backup/emergency use only. To do this required the amplification of the signal with the aiming orders without changing its value by more than 0.001 degree or so (even a small error could make a big difference at longer ranges or against higher-speed targets, especially with anti-aircraft fire). Attempts to do this with direct-current "stepping-motor" systems -- most warships used DC power systems throughout at this time -- with tiny jumps from value to value, as in the second hands of some clocks, had never been successful, with errors jumping upward in sync with the signal strength needed to run the controls automatically. What was needed was a very fine control range method that could be amplified in strength with no change in the error. The solution was to change to alternating-current (AC) signals and use transformers -- the same method used in homes to change the higher-power electrical pole voltages to the much lower one used in the home wall outlets -- to adjust the signal strength up and down. To keep the same error required a very precise way to measure the values being transmitted (any signal could be converted to this system, not just angles for gun aiming, note) and a way to shift the signal strength without changing the precision of the original measurement/calculation (this can go to and from any device, not just from the computer to a gun mount). The solution used by the US Navy was the "synchro" or "selsyn" ("self-synchronization") technique. The information to be transmitted was changed to an angle value on a 360-degree dial by appropriate gearing/electrical conversion and then this was sent to the transmitter for output. The transmitter had a magnetized needle on a pivot that rotated to the angle given to it. Around the needle in an equilateral triangular set of three AC electromagnets was placed on the same plane as the needle, so when the needle moved, it changed the strength of the output to each of the three coils slightly in a unique manner for any angle value. These three currents could be put into a single voice-radio-style transformer/amplifier to boost all three by exactly the same amount and this boosted current sent to the receiver where it too had the three coils and its own magnet needle, which the now-strong signal on the three coils pushed to match the position of the needle in the original transmitter. Shazam, the signal was "teleported" to the device attached to the receiver, no matter where it might be on the ship. To handle slop in the needle position, a second geared needle system with a 36-to-1 geared needle (10-degree range) was also created by the transmitter and sent parallel to the the 1-to-1 signal and, using a simple geared or electrical network, the two were combined to make the final geared needle output match the original one within any accuracy desired (even higher secondary adjustment needle ratios could be used if, rarely, even higher precision was needed). Instead of vacuum-tube-enhanced transformers, the Germans used magnetic amplifiers (also used by the US in some systems after WWII) with similar results. The original British system, the "Magslip", was a hybrid requiring the human to move the controls to within 10 degrees of the aim point before the RPC could cut in; it was replaced after WWII by a more conventional fully RPC system, as was done by everybody else. Against surface ships, which were rather slow for the most part, the follow-the-pointer system worked OK, but it failed badly during WWII against smaller attacking aircraft -- not straight-line horizontal bombers -- as the aircraft got faster and more maneuverable. The analog synchro-type systems remained in use until digital equipment began to replace them during the 1970s, though it took many years to finally do this, given the slow overhaul rate of warships and the "if it works, don't fix it" logic when using older equipment...

Before your channel, I had no idea how sophisticated these systems were.

Optically: I see that we'll definitely hit that target Depression: We'll never hit that target

As an old fire controlman, I enjoyed the heck out of this. The picture of the switchboard brought back memories: we had motorized switches, and when they rolled, it was like have a couple dozen pistols firing right next to you. You brought out the complexities of the fire control solution really well, and with more humor than my instructors in school. Except for Petty Officer Wilson. He always liked to say that us wimps with the new-fangled digital computers were slaves to the AC. His Mk 56 analog computer could take the heat. So it got a little warm; his accuracy went up!

I was so excited to see a photo from the film "Master and Commander" one of my absolute favorite movies of all time. The depiction of naval battles in that film were so authentic. Love it.

"I took ballistics in school. Fascinating subject. Things go up, things go down!"

"A ship always undergoes a certain degree of roll" *image of half sinking ship* never change Drachinifel, never change

I have researched this topic for the last 30 years; I even got special access to the research library at the Mariner's Museum. This video states the problems of fire control very well. That inventive men found ways to put their mathematical models to use on actual ships, using trains of gears and mechanical whatnot, is amazing. The problem is so much easier today, with digital computation. Of course, naval artillery is almost an afterthought; missiles are the thing.

I was present and observed from the flag deck what was one of the finest and most accurate shooting ever by a ships guns. When during Operation Praying Mantis. the USS Merrill fired about 105 shots in continuous uninterrupted shelling of an Irainin oil platform from about 3 miles out. All shots fit the mark! These were air bursts. Made more demanding, because one end of the platform had containers of gasses, that we did Not want to hit. It was feared the gasses if released might drift to "friendly" territory. Both for and aft guns were used. The enlisted gunnerry personal responsible for the upkeep of the guns were awarded medals.

"Humans don't react very well to heavy shell fire" Drachinifel, 2020

Littorio Class Battleships: "I've got you in my sights." "And you." "And you!" "And all of you!" "...And yes, you too!"

Another thing the FCS needs to take into account is the wear of the barrels overall and number of rounds fired in a particular engagement, as both of these will also affect the ballistic trajectories of the rounds. Another thing that can also be important to consider is masking data, which is the location and height of external objects (such as buildings and trees) relative to your position as well as the target. Obviously not as much of a concern in the open ocean (except in fleet actions because friendly fire is generally disliked), but is also important to consider when engaging in shore and coastal bombardments. This video is good but really just scratches the surface on many of the concepts and factors that go into artillery ranging and ballistics. There is a lot to consider and one can spend literal weeks just learning the concepts.

Stepfather worked in a dismantling yard in the late 1970's where the cruiser Bunker Hill and carrier Ticonderoga among others. He brought home several complex prisms. They fun to play with in the sun, creating light spectrums otherwise known as rainbows around the room and made interesting paper weights.

I remember when I was in the RAN on HMAS SWAN, I did some work on the fire control computer, it was an ANALOGUE MECHANICS computer, a glorious sight to see, this is around the mid 1980's. EDIT: As a side note, On HMAS SWAN we did a RIMPAC and a wargame, we were in the USS Missouri battle group at war with the Nimitz group (SWAN is ASW), during that we got a gunnery display from the Missouri including a close range (for us) of a full broadside firing. We were located only a couple of miles away! It's a memory that will never leave me..

*"Significant emotional event" * "Oh bugger, the ship is on fire!" when?

Actually, higher humidity air is less dense than dry air. Really enjoy this series. Thanks!!!!!

This video mentioned the coriolis effect regarding calculating the rotation of the Earth. My Dad was in U. S. Army Americal Division artillery on Guadalcanal. He told me about calculating for the Earth's rotation on the 6.1 inch guns when given long range fire missions.

"Genetic hybridization was frowned upon" Drachinifel, 2020

All I could think about when seeing the early rangefinders was "frickin Hammerhead sharks with frickin laser beams"

My father was a fire control officer on a tin can in WWII. He had some “interesting” stories to tell. “Almost” only counts in horse shoes, hand grenades and special weapons.

One of the less well known David vs Goliath scenes of the Action Off Samar were fighters from the TAFFY carriers trying to take out the rangefinders on the Japanese battleships with machine gun fire. I read this years ago in Combined Fleet Decoded which was mostly about cryptanalysis in the Pacific War. Effectiveness was not reported.

I did my university dissertation on WW1 Dreadnought Fire Control Systems - specifically the 'controversial' argument concerning the merits of Arthur Pollen's 'Argo Clock' system verses Lt. Frederic Dreyer's own in-house system, and the later arguments between academics on the issue (centred on Prof. Jon Sumida's pro-Pollen 1989 account 'In Defence of Naval Supremacy' and later John Brooks' 2006 rebuttal 'Dreadnought Gunnery and the Battle of Jutland - The Question of Fire Control'). Overall, I found it a fiercely argued debate with a strong suggestion that the Argo system was probably superior - when the system's gyroscopes worked as intended - but that Dreyer used his position as Assistant to the Director of Naval Ordnance (a certain John Jellicoe) to get his own system approved over Pollen's. Sumida has pointed to the fact that at Jutland, HMS Queen Mary had an Argo Clock, and had consistent and effective firing results right up to the moment she got citadel'd. Pollen, however, wasn't blameless; his system relied on gyroscopes to work effectively, and they proved finicky. Plus he was asking for a lot of money for his system, with the Admiralty ultimately opting for Dreyer's cheaper system. POllen himself would later go after Jellicoe after Jutland in a series of accounts and articles which have an element of 'sore loser' about it; as Jellicoe himself said, "It fell to me to turn down his inventions on more than one occasion". Sumida argued this was what led to the Royal Navy's prized and expensive battlecruisers having such poor gunnery during the Battle of the Falklands and later at Jutland - the high speeds of the ships causing heavy vibrations, leading to ineffective plotting of firing solutions, and that the Argo system would have eliminated these problems. I would be very interested on your take Drach. It's a highly technical topic as this video has showed, but for me it has a personal connection given my previous work.

I am finding it difficult to settle down and watch this due to constant interruptions from Japanese torpedo boats.

I figured naval gun targeting consisted of a crewman of one battle force calling out an alphanumeric grid coordinate, like "D-9", and someone from the opposite force replying with "hit" or "miss"! 😆 Great video!

And I thought launching and recovering aircraft from ships was complicated. It seems straight forward by comparison.

Back in the '80's, the US Navy's Fire Control Tech 'A' school was at Great Lakes training base (probably still is). There were a few antique range finders in the plaza of the school that us students could fiddle with. Yeah, 1 minute with an optical range finder WILL give you one helluva headache.

In the early 1970s while in the middle of the Pacific Ocean, I once experienced a range-finding fire control exercise aboard the U.S.S. Jason which was then equipped with four 5"/38 caliber guns in individual turrets. Quite a large crowd assembled on the fantail as first the target (a 55-gallon drum) was unceremoniously dumped overboard, and after a polite interval the superfiring "X" turret let rip with an ear-splitting blast. Within moments a bosun shouted out from the boat deck "CEASE FIRE ... CEASE FIRE". Turns out that the blast had shattered the windows on every vehicle we were carrying on the boat deck, including the captain's car, the ship bus, etc. End of firing exercise!

Thank you, I enjoyed this immensely !! I was educated an artillery officer in the Norwegian Coastal Defense, in the beginning of the 80'ies. You do this very accurately - are you yourself of Naval origin ? In my time, our fortresses had at least 2 main systems, and very often radio and cable communication to nearby batteries for the option of being controlled by their systems. As a last resource, the gun commander could as you conclude in your video - independently control the firing himself (yes - we were only guys at that time) That off-course was immensely fun, and is still of my most found memories of all I have experienced in my life. With a crew of 18, directing the fire independently - very often sitting on side correcter position, following the target, and see the impact , feel the power when the gun is fired - make split second correction orders, and firing again - o'boy, I was alive !!

really makes you appreciate how far technology has come in such a short amount of time. what back then took tons of precise, vulnerable, expensive, and complex equipment operated by large numbers of sailors to do, you could today do better with a 500$ laser rangefinder and a 200$ Laptop, and if you get a 10$ antenna you could even get largely accurate weather data transmitted to you.

Flat Earthers: The Earth is flat Every artilleryman: *[Laughs in mathematics]*

The MK 68 GFCS also accounted for: Barrel wear- each round fired removed a tiny amount of material from the barrel which would affect the seal. How many rounds have gone through the gun was inputed. Local gravity- Gravity is not constant on this planet so what the local gravity is has to be accounted for. Magazine Temperature- Magazines are deep in the ship and will just about always be a different temperature that the situation above deck. The powder charge will be at magazine temp and this must be accounted for since it affects the volatility of the charge.

Extremely interesting and fascinating. I have been reading James Hornfischer's book "Neptune Rising", a superb account of the US and Japanese Navy battles at Guadalcanal in 1942. The average person can't comprehend how naval gunnery works, and your video is excellent in explaining range-finding and fire control. There is one thing missing from your video, however, which is obviously impossible to include: what is happening during an actual naval battle. While a captain and his crew are making all the incredibly complicated calculations to fire at the enemy, the enemy is doing the same. Whoever strikes first gets the upper hand. Suddenly dozens of shells and torpedoes are slamming into a ship, causing horrendous explosions, massive damage, raging fires and shocking human carnage and death. The Guadalcanal battles were so unbelievably violent and enormous in scale that it totally defies belief that human beings can go through such experiences. Naval warfare is absolutely terrible in every way.

I was briefly a Gunner's mate in the US Navy but never got to the detail of how fire control systems work. Thank you for a fascinating video.

The enemy ship is bearing down on us! They've opened fire! Do you have a firing solution yet? Umm... Well, Sir... WHAT IS IT??? Sir, the fire control computer just started downloading an update... There's only one bar of signal...

Drach: "Genetic hybridization with hammerhead sharks is frowned upon" Also Drach: 12:55

All of this has puzzled me for years. I've only heard very brief descriptions on the subject in the past. This was a very informative video.

The way they did is really mind-boggling. Very cool video, always fascinated by the technical aspects. 60 minutes that felt like 10, but could have been 120

After viewing this video detailing how complicated naval gunnery really is, all I can think of is how the HMS Warspite and the Scharnhorst both somehow landed world-record shots on moving enemy ships at ranges of 15 miles/24 kilometers away while moving at high speed. Imagine the calculations on those shots... Great work, as usual, Drach.

This really makes me appreciate how good the gunnery must have been on HMS Duke Of York to hit Scharnhorst with it's first salvo in the middle of a storm.

This came out about 600 times longer than I expected!!! Please have a great Memorial Day weekend but PLEASE! NEVER FORGET! I was a Target Acsuision specialist (USA Artillery- 17B) during the late VN war and while I never went into combat, and we used radars, albeit tube-based rather than transistor-based, and also utilizing analog computers (electro-mechanical, gears, etc.), we did have to utilize optics for some of our fire missions. As I said just prior, it's true we never used large stereo optics as described here ( we combined both visual scopes along with the radar to do the job correctly on many fire missions) but one of my Warrant Officers was one of the designers of our radar set! Chief Perkins, an old 30+ year soldier (A black man BTW) with... not many teeth left in his awesome head, but was a superb trainer of men! He took a shine to me as a high school flunkie and took me aside to learn Trig, in a real man's use of the science and was nothing short of stunning in how he made sense of how HIS radar worked, but about so much more! He made Algebra seem simple and I learned enough to go on to college after I got out! I broke the man's heart when I did get out because he had plans for me! He even had me banned from Ft. Ord! I miss you Chief and I'm sorry for wasting your time! ... except, in the end, I don't think I did, since I went on and got my degree as a EE and did a lot of cool stuff in my civilian career! You were truly an inspiration to me and showed me that wasn't some dumbass wandering about the boondocks of one's life as so many people I've known have done! Chief Warrant Officer ◆◆◆◆(4) Perkins! I salute you, sir, and can say without hesitation, you were easily one of the top five people I've ever met in my occasionally GREAT (but not always) life!!! You cared for everyone under you, BUT (...and this is a big but!) you truly helped me along to extract my head from my ass! I think of you often and I'm sorry I let you down and left the service which you made me grow to love! Though I've never had a shot fired at me in anger (there were a couple of incidents involving drunkeness (stupid Grammarly keeps trying to tell me that it's spelled 'drunkenness'!), but we won't talk about that here...), you taught me how to be a good combat soldier and I'll never forget you! For some reason, I still miss my pot, P-38, and OD cotton fatigues... starch and all! A man of character and integrity does not come around often, so if anyone reading this encounters one, I'd just ask that they realize it quickly and appreciate the awesome opportunity to learn and feed off of him/her... Thank you, and all of the VN Combat Veterans who paid that ultimate sacrifice... yesterday, recently, and those times to come!!! P.S. I got my GED while in the Army... P.P.S. To everyone who was bored enough to read this, enjoy your weekend, but please(!) never forget the reason you get Monday off this time of year! Let's turn 2021 into a great year! (yeah yeah... I'm just as skeptical as you... one can hope though, can't they?) P.P.S. So how 'bout those stereo optics, ay? P.P.P.S. ... and no! I was not 'name'... nor 'color'-dropping about Chief Perkins, but it does seem to raise eyebrows when I mention his race. He was indeed one of the developers of our radar set., an AM/MPQ-4A (Q4 to those using it) Target Acquisition Radar. A fantastic officer and, as I said, VERY caring of the men who utilized equipment he had a very large hand in bringing about to the point it went in combat. P.P.P.P.S. ... We were also the only unit in the field with electricity which allowed us to have a very active coffeepot, such that the Battalion Commander rarely missed a stop at our field position to have a cup of some of the worst coffee ever brewed! P.P.P.P.P.S. Damn!!! It IS really spelled DRUNKENNESS! Maybe it's a good week to quit... (See Lloyd Bridges)

Drach, whenever you make it to the States, if you get to the USS Massachusetts, when last I visited her in 1999, the local control fire control computer in Main Battery Turret 3 (Aft, accessible via the downward-facing hatch in the overhang ) was there, and you could crank inputs into the various dials - range, own ship speed, course, target relative bearing, target speed, wind direction and velocity, etc.. - also the turret local control rangefinder optics were unhooded and afforded a fine view of the Fore River Bridge. As I was the only adult motivated to do the minor gymnastics to enter, I found myself running an impromptu gunnery exercise with a group of boy scouts... "OK, you're the gun captain, you're the powder man, you're the rammer, you're the talker...." Great fun, except that my wife, with a very cranky toddler in tow, was looking for me, and apparently had been for some time - and could not figure out WHERE in HELL my voice was coming from. I had already vanished for an extended period while exploring the engineering spaces and our daughter had run out of interest roughly an hour previously. There were consequences, but fortunately the marriage has survived.

The first time I went to the Yamato Museum, they had a special exhibit which included some replicas of components of the ship, like a main mirror and parts of the main range-finder. The scale of those things is quite difficult to convey, but I was completely blown away by it.

A suggestion for a related future post: the plotting screens used in WW II. Side-lit plastic or glass boards where dark clad crew drew with grease markers enemy and friendly vessels. These crewmen were taught to write in reverse for the command to be able to see from the other side. Like some kind of live action sci-fi computer screens. Maybe a video on command room operations if that is a proper tern. Loved this post btw, the lavish amount of technical detail and dry wit on top of that was excellent,

This did a good job of helping me understand how ships can fire hundreds of shells and achieve very few hits. Well worth watching. Thanks very much!

This may be the best video on battleship technology I've ever seen. Questions I never even knew I had were being answered one right after another. Absolutely terrific job.

Nitpick: 46:29 - actually moist air is *less* dense than dry air. But once again very informative video - thanks.

The roll angle of the ship at 42:00 might slightly exceed the design specification of the turrets and the fire control system. In a situation like this, you probably wish you had watched the "Survival at Sea" episode instead ;-)

This was one of the best videos on naval gunnery I've ever seen. It's a little more complicated than taking a shot at that buck standing on the other side of the field grazing away while you watch him through your scope.....😜

While you are correct about the fact that moist air will react differently than dry air, you are backward as to density. One molecule of water will displace one molecule of nitrogen or one molecule of oxygen. Water has an atomic weight of 18, 2 for the two hydrogen atoms, and 16 for the oxygen. One nitrogen molecule, N2 has an atomic weight of 28. One oxygen molecule has an atomic weight of 32. That moist air is less dense than dry air is well known to all pilots. However, this comment should not detract from the very large amount of valuable information you are providing. Keep up the good work.

Last time I was here this early, Kido Butai still had 6 operational carriers Oh, and: Hooray for the long awaited special!

Two nitpicks. Humid air is less dense than dry air. In gaseous phase, all molecules take up the same amount of space. And because water is one heavy oxygen atom combined with two extremely light hydrogen atoms, but regular oxygen and nitrogen is two very heavy atoms, water vapor is less dense than the rest of the air. A hot barrel squeezes a shell less than a cold barrel. Take a loop of wire or something; now imagine the metal expanding. The loop of wire will push against itself along its length, making the entire loop bigger. A gun barrel is the same thing, it's just a thicker, elongated loop. This is one of several reasons it's harder to start a cold engine than a hot one: everything is squeezed together more in a cold engine and there's more friction.

My dad explained the range finders to me when I was kid in the 70s. He was a Chief Gunner.

I have to say that I have never really had much interest in naval stuff, but I truly love your long videos on topics such as these. Thankyou!

As a former Fire Direction Controlman, I approve this message.

Admiral Cunningham noted before the Battle of Cape Matapan, at point blank range even a gunnery officer can hit the target. So he closed to point blank range and blasted away.

I'm gobsmacked! Never realised there was so much complexity in range finding, gun laying and fire control. Even more impressive is that you can talk about for an hour and it is understandable and fascinating. Well, I admit I will benefit from watching it again and that I'll happily do. It's wonderful in this day and age that spoken word still has such power. Thank you and keep the information coming.

I've learnt more by watching 5 of your videos than 11 years I spent at school :)

Loved the picture of “Lucky Jack” Aubrey. Some of the RN ships had a reputation for accuracy, mostly due to competence and practice. The radar fire control made a huge difference in the Battle off Samar.

@37:25 That brings back memories of my time in the USN. As a fire control technicians we spent several weeks stepping through the various calculations, corrections, and error corrections for gun fire. We used the Ford Mk 1A computer as the base for this as we studied the maths. The basic elements of the problem don't change and are the same for surface and air targets. Thanks for a great overview of the history and technology.

Excellent ! Very instructive and historically informative. Loved the strategic touches of humor.

Kudos to Drach; I love listening to your channel while I am calculating the unappreciated effect of Jupiter and the other planets effects on the center of mass rotation in our solar system that is more applicators than you might think. Please carry-on.

There's an amazing set of videos on the Ford Fire Control system used by the US Navy. Some functions I had no idea you could solve mechanically...and simultaneously. The initial work on American electronic computers [ENIAC] was not code-breaking like the British "code bomb", but to calculate ballistic trajectories and firing tables for heavy artillery for the US Army and heavy naval cannon the Navy Dept...page after page of ballistic data.

Flat Earthers: "Pilots are trained to assume a flat stationary plain." Artillery: "We train our personnel to account for the curve and spin of the earth and we know it works because we hit the target." Flat Earthers: *covering ears* "La la la la la! I can't hear you!"

Thank you for sharing this information, you are a gifted person, and an excellent instructor/teacher. I can watch your stuff over and over and always learn something new.

I would like to commend you on the delivery of your explanations. I have had to explain many complex engineering things to many people over the years and to my mind you have done an incredible job of taking us through the many factors involved. Much harder than it sounds. Well done.

24 range finders....jesus so they deployed essentially the same philosophy of put something here motto as the americans.....just with range finders and not guns.

Significant emotional event.....I see what you did there sir....bravo. I'm so glad some of my favorite KZfaq channels have met and talked. Fantastic video as always Drach. Edit....can you imagine being Agincourt's gunnery officer. It would be so tempting to fire ALLLL the guns at once. You may not hit anything but boy it would look impressive.

Thank you for thoroughly guiding us through these both complex and sophisticated systems of early naval long range gunnery!

Highly informative, great photos, clear narration and an interesting subject I knew little about...until now. Thank you for the excellent video.

I served my apprenticeship in Barr & Stroud in the sixties and later I managed to get my hands on a Barr & Stroud range finder now in my collection

0:35 This is an interesting picture of USS Iowa BB-61. This was taken when she was first commissioned in 1943 during her shakedown cruise (before her bridge was enclosed). If you look closely at her turrets towards the backs you make out a range finder "ear". These were installed as redundancy incase the main range finders on the fire control tower took a direct hit. Turrets 2 and 3 had a stereoscopic Mark 52 range finder and was accurate up to 45,000 yards by themselves. Turret 1 had a coincidence Mark 53 range finder and had had a special astigmatic lens which allowed it to zero in on a target such as a searchlight. Since turret 1 was lowest on the ships its range was slightly less than 1 and 2. During the early 1950's when radar was taking the place of optical range finders, the special range finder on turret 1 was removed from all 4 Iowa's as weight saving and due to the fact that radar made the Mark 53 redundant. Turrets 2 and 3 retaind theirs "just in case." If one were to look closely at any of the Iowa's today you can still see where they welded new armor patches on the backs of turret 1 where the "ears" once were. Source: www.navweaps.com USA 16"/50 (40.6 cm) Mark 7

Very informative throughout. I have a long-term fascination with naval gunnery and fire-control systems. Very well done!

RIP grandpa, I was to young to remember his stories very well but he was a part of fire control systems on a heavy cruiser. I just remember him talking about some diamonds on a circular thing and a guy at his back dealing with fuse timing on the shells.

Littorio's rangefinding gear was kind of like putting racing tires on a tractor.

To Drach: thank you for your amazing videos. To Drach's followers: thank you for at least appearing to be reasonable people in the comments section, the lack of totally random/dumb/ridiculous/offensive comments honestly makes my day. :)

This was a cool video and I plan to re-watch it with my undivided attention. It covers a topic which has always been a big-time curiosity to me. Thank you Mr. Drachinifel!

Much respect for the guys that ran these systems but also huge props to you for the headache inducing chore of explaining them. Man I want to commend you for a job well done. There were points where I could see your face contorting just by listening to your voice. You earned a new subscriber.

Ah yes, the constant inquiries about the temperature of the powder and whether or not its raining. We always gave crap to the fire control guys because they sat in a warm, well lit truck on a comfortable chair while we the gun crews stood outside in total darkness in -30 celsius snowstorm but I suppose they had their own headaches, literally.

Great stuff. Those mechanical fire-controll systems are incredible. The complexity off those things... depending on how much of a nerd you are for machine engineering, it's either a dream or a nightmare. The things you can do with simple cogs and cams if you put your mind to it...

Excellent video. I knew it was difficult for one warship to hit another with a shell. But you really brought into realty just how VERY hard it is to do that. Sooooo many variables. Thanks.

Note that humid air is less dense than dry air. People often assume that humid air is just water vapor added to air but the water vapor actually displaces the air. Water has a much lower molecular weight than 'air (nitrogen and oxygen)', causing it to reduce density when it is combined with air.

Everything before modern computerized systems sounds like the SWAG* method. *Scientific Wild Ass Guess

There are so many clues in this presentation that convince me that Drach does not think that Da. Erff. Izz. Flatt!! Bravo!

My Dad worked for Ford Instrument repairing and calibrating the Mark1. Though a "civilian", he spent most of his time out of Pearl at sea.

Most fascinating vid so far in the series. I am boggled by the complexity, unboggled by the explanations.

Thank you so much for creating and uploading this video. Ever since I started watching your channel I was wondering how this entire topic worked because the terms range finder and fire control came up frequently. I tried looking into it and you do a much better job of explaining it. Much appreciated!

Gunnery, the art of blowing things up with math. It's amazing how complex these machines were. It's almost a shame they're obsolete, what wonderful pieces of engineering.

I love all the humor peppered through out your videos, makes it all the more entertaining with the dead pan delivery. Keep up the great work!

This is an excellent presentation of a very complex topic Drachinifels.

To recap: IT'S COMPLICATED!

This one of the best explanations about getting range and and targeting with all of its complications. Very Impressed.

Great fun! Thank you for the lesson on fire control. I worked for one of the inventors of the aircraft carrier landing system (ACLS) that automatically landed aircraft on carriers. The first system was successfully tested in 1957. It was an analog computer based system but was somewhat simpler than fire control. Side note: humid air is less dense than dry. H2O has a molecular mass of 18, dry air is closer to 29 g/mol. It is a common mistake due to how heavy it feels in high humidity!