Basic Mechanisms In Fire Control Computers (1953) [video] | Hacker News Reader

Basic Mechanisms In Fire Control Computers (1953) [video]

youtube.com

348 pointsteqsun114 comments

In 1989 I was a data systems tech on a Destroyer going through some overhaul at the shipyard in Pascagoula Mississippi. Moored right next to us was the battleship Wisconsin. Huge relic from WW2 but still going through modernization. A bunch of us that worked on combat systems got invited for a tour of their fire control systems.

Wow. Just wow. All mechanical computers calculating fire control solutions for the big 16 inch guns. The guys giving the tour were well beyond the age for regular military retirement. Come to find out, they were all reactivated because practical knowledge of the mechanical computers had since left the navy. That was a very cool day.

I remember seeing one of those computers on Wisconsin, but I only saw it after decommission, as a museum piece. Those computers are truly mind boggling, if you're reading this and you're close to Norfolk you should visit battleship Wisconsin.

same goes for being in SoCal and going to visit the USS Iowa in San Pedro. it also has similar mechanical computers, it's a fantastic day spent clambering around the ship. sometimes they do "stay overnight in the bunks" nights, I can highly recommend it!

For anyone along the Northeastern corridor, the USS New Jersey in Camden is another well-preserved Iowa class museum ship.

The Battleship New Jersey has a good youtube channel where the head curator walks you through some things.

https://www.youtube.com/@BattleshipNewJersey

They also sell broken parts of the ship that they fix up as souvenirs, like the entire deck's worth of wooden planking, and for $1000 you can take a tour where the mildly charismatic head curator takes you into the smallest and hardest to reach parts of the ship!

Or fire a 5 inch gun, you know, if that's more your speed.

> Or fire a 5 inch gun, you know, if that's more your speed.

Depends on what the target is.

For $1k it's just a blank round.

But if you donate $1M, you're allowed to shoot the USS New Jersey's curator Jordan with an HE shell from the 16" guns.

If you watch the channel you'd know it was HC - high capacity.

My uncle was on the Wisconsin and operated the big guns during the first Gulf war.

I never really had context as a kid for how large that ship is, and was just astounded by the distances they would shell.

This was right before the gulf war so I may have met him! Assuming he was a gunners mate, that crew had a lot of moments of touching history. Besides mechanical computers, it’s a really dangerous place since they had to handle massive bags of flash powder.

My ship was near the USS Iowa when turret two went up. A sobering experience when you think how much risk the turret crews are in just by doing their jobs.

For those like me who didn't get this reference:

"On 19 April 1989, an explosion occurred within the Number Two 16-inch gun turret of the United States Navy battleship USS Iowa (BB-61) during a fleet exercise in the Caribbean Sea near Puerto Rico.[1] The explosion in the center gun room killed 47 of the turret's crewmen and severely damaged the gun turret itself."

https://en.wikipedia.org/wiki/USS_Iowa_turret_explosion

thanks, I ended up reading the whole thing. If you watched a movie about this you'd think the writers went too far.

Apropos: https://www.navalgazing.net/Fire-Control-Part-1

By the end of WW II American torpedoes were automatically programmed (direction, speed, fusing) before firing. The heavy calculations would be done by the shipboard firing computer while the parameters set would be used by the simple computer on the torpedo (which had inertial guidance). I struggle to imagine how people managed to design such things with just pencils and slide rules.

WW II American torpedoes didn't have inertial guidance. They used gyros for directional control and just ran in a straight line after making a single turn onto the set course. Occasionally the torpedo would get stuck in that turn and run in a circle. Towards the end of the war the Navy also started introducing homing torpedoes, but those didn't use inertial guidance either.

A gyro by definition IS inertial guidance.

Not really. By definition an inertial guidance or navigation system has to do some sort of integration of inputs over time. Gyroscopes are typically used as part of inertial guidance systems, but connecting a gyro output directly to a rudder input wouldn't by itself be considered as inertial guidance. The device wasn't doing anything to calculate absolute position based on inertia.

> Occasionally the torpedo would get stuck in that turn and run in a circle.

Well that's not a great failure mode, if it can come right back at vessel which launched it ... imagine trying to implement a self-destruct failsafe with that tech back then ...

At least two US Navy submarines were sunk by their own torpedoes making circular runs. The main failsafe mechanism disabled the detonators until the weapon had run out a certain minimum distance but obviously that wasn't effective in circular runs.

https://www.usni.org/magazines/naval-history-magazine/2011/j...

Clear the Bridge [0] was an autobiographical account of WW2 from the captain of the Tang. O'Kane covers the experience of this incident in the book.

While two US Navy subs were known to be sunk in this manner, there remain several subs not claimed by either Germany or Japan that just never returned.

0 - https://www.amazon.com/Clear-Bridge-Patrols-U-S-S-Tang/dp/08...

This may have been common enough that I distinctly remember it as something that could happen when playing Sub Battle Simulator in ‘91 (or around that year): https://en.wikipedia.org/wiki/Sub_Battle_Simulator

Not exclusive to the US though, check out the "Torpedovorhalterechner" ;)

http://www.tvre.org/en/torpedo-fire-control-system-on-german...

Scrolling down there's a nice photo with removed cover.

Yes, in fact even a Harrier Jump Jet was designed with pencils and a slide rule!

I.suspect they used tabulators and other such mechanical calculation devices, with a higher precision and faster speed than a slide rule.

BTW these computers were mostly very functional, in the modern sense. They took inputs from instruments and controls, and computed functions, all usually continuous, smooth, real- or complex-valued. These functions' values, computed as voltages, frequencies, angles, etc were directly controlling some actuators, rudders, throttles, etc.

It's also highly compositional, as in applying relatively simple functions to results of other such functions, etc., which you can reason about analytically, and can plot on paper or an oscilloscope as a part of development and testing loop.

Disclaimer: all my hands-on experience with analog computers is from a one-semester course decades ago, using analog electronic, not mechanical devices.

There were also a large number of captains, who refused to trust anything coming out of the navys design bureau and testing facilities and personally made sure, that computers were never used or even ripped out, to only use a "working" impact fuse. Those distrusting captains continued there "protecting the crew from dysfunctional crap" missions well up into the vietnam war. Engineering failures have serious consequences and ripple effects.

I had a co-worker at the Navy Yard that said he was an Anti-Aircraft tech during the Korean War. When he said they used 'mechanical computers' I had to stair up into space for a minute to figure out what that meant.

In 1981 I was just out of high school and had a summer job at NUWES - Navel Undersea Warfare and Engineering Station in Keyport, WA. I was in a group that was refurb'ing fire control computers from submarines. They kind of looked like those stand up video game consoles that became popular in arcades soon after - except these cabinets were made of solid aluminum. They were full of gears and resolvers - analog computers. The "display" was all analog. And they were all being replaced with new gears and resolvers. I recall that there was another group nearby that was experimenting with microcomputers - they had some S-100 boxes like IMSAI 8080s.

The US Navy's old training materials are fantastic for learning about various technologies.

I think their masterpiece is "Basic Hand Tools" a handbook written in plain English that describes the use of practically every hand tool ever invented.

"Basic Hand Tools" on the hammer:

>Whoever conceived the idea of cracking a nut with a rock unknowingly invented a tool. When a later genius tied a stick to the rock, he invented the first hammer. There have been a lot of improvements since that humble beginning.

The modern version "Tools and Their Uses" also covers machine tools but is less fun.

Do you happen to have a link to the "Basic Hand Tools" version?

https://archive.org/details/UseOfTools1945/mode/2up

Thanks for posting the link. What a great book.

NEETS is another to add to the list. A quite literal full stack guide to electronics from the basis of matter up.

"Navy Electricity and Electronics Training Series"

I found the "textbook", but is there a video series associated with it?

Not just military training videos, older ones in general are often superior to what gets made today. My favorite is probably this one on vehicle differentials:

https://m.youtube.com/watch?v=yYAw79386WI

Periscope Films uploads a lot of public domain US government material, and has it decently organized. The asbestos series is also interesting, hindsight being 20-20.

See https://m.youtube.com/@PeriscopeFilm/playlists

I like this even more.

AT&T Archives: Similiarities of Wave Behavior

https://m.youtube.com/watch?v=DovunOxlY1k&pp=ygUOYmVsbCBsYWJ...

Jam Handy films were amazing. You could show this to an audience who was morally opposed to learning about differentials and they’d still learn about differentials.

I've never been a car guy. While I've heard of differentials, I never understood what it was. Thanks to you posting this video, I now understand what a differential does and how it does it.

(I found playing it at 120% speed to be a good balance between comprehension and engagement)

I just downloaded (thanks to other commenter below) and would question the "use" part. What is the "peen" end used for? Having read the section on hammers I still don't know. (Just re-skimmed the section and I still don't know.)

Hitting things ;)

https://en.m.wikipedia.org/wiki/Peening

I dimly recall making an ashtray (hmmm, not sure that would fly these days) in high school metalwork class by beating out a piece of copper sheet with the peen until it was suitably concave.

https://en.wikipedia.org/wiki/Ball-peen_hammer

Is the original this one?

https://archive.org/details/HandTools1944/page/n87/mode/2up

I will never pass up an opportunity to use this joke:

Everything is a hammer, unless it's a screwdriver. Then, it's a chisel.

Not a joke and different domain, but similar structure and also noteworthy:

Everyone should meditate 2 minutes a day, unless he's busy. Then he should meditate 20.

"The Navy is a master plan designed by geniuses for execution by idiots."

- Herman Wouk, The Caine Mutiny

This is completely true. 18-20-year-old kids launch and arrest aircraft on a carrier while simultaneously performing an underway replenishment, and it's just another day.

I highly recommend "Between Human and Machine Feedback, Control, and Computing before Cybernetics" by David A. Mindell

This is a great primer on one facet of the Navy and "technology".

So much of early computing has some tie back to the navy. It isn't an accident that Grace Hopper was an admiral and not a General. Much of Cray's early work is littered with "Navy" (including his transfer from Europe to the Pacific).

It's a fascinating bit of WWII and Post war history that is worth exploring.

That history extends back the other direction too with mechanical tide prediction machines, or even early marine chronometers for navigation - the OGps if you will.

Navigation and gunnery have always been driving forces for mathematical innovation so there are often naval connections to important discoveries and inventions.

But don’t sleep on the importance of land-based artillery and military surveying and cartography as motivation too. Long range naval gunnery with these kinds of mechanical computers to take into account things like course, speed and rolling motion, was all building on earlier static land-based gunnery methods using tables and nomograms derived through complex calculations - some of Babbage’s difference engine work was calculating gunnery tables.

This is the whole conceit behind Neil deGrasse Tyson's book "Accessory to War":

"Accessory to War: The Unspoken Alliance Between Astrophysics and the Military is the fifteenth book by American astrophysicist and science communicator Neil deGrasse Tyson which he co-wrote with researcher and writer Avis Lang. It was released on September 11, 2018 by W. W. Norton & Company. The book chronicles war and the use of space as a weapon going as far back as before the Ancient Greeks, and includes examples such as Christopher Columbus' use of his knowledge of a lunar eclipse and the use of satellite intelligence by the United States during the Gulf War. While speaking on the book, Tyson told National Geographic that he regards the collaboration between science and the military as a 'two-way street.'"

FWIW Tyson is quite critical of the application of astrophysics research to military ends.

https://en.wikipedia.org/wiki/Accessory_to_War

There’s a reason that the UK mapping agency is the Ordnance Survey.

On that note: if you read a lot of technology books and/or research papers and you pay attention to the "acknowledgements" section, you'll likely observe that it's quite frequent to find something to this effect in there:

"This research funded in part by a grant from the Naval Research Laboratory, grant number XXX-YYY-ZZZZZZZZZZ".

This aside from similar notices mentioning DARPA, NSF, and other funding bodies.

To get a direct feel of how it is working with such a 'computer': the UBOAT game on Steam (spiritual successor to the Silent Hunter games) has somewhat recently added a Torpedo Data Computer as used on German Type VII submarines:

https://store.steampowered.com/news/app/494840/view/37127138...

The user interface is surprisingly intuitive even by today's UX standards.

Great video! I love the simple straightforward presentation, it explains the concepts so well. The many applications of cams continue to impresses me.

The fundamentals of mechanical computers go back much further, well into the 1800s and possibly even earlier. Much of it has its roots in clockwork.

> it explains the concepts so well.

Indeed. Watching the video I found the practical and visual illustration of math concepts when implemented in mechanical gears to feel intuitive in a way I never felt from chalkboard math instruction. As a person who's always struggled with traditional algebra and up math education, seeing it presented in this physical way really felt fundamentally more accessible to me. Like I strangely felt far more 'connected' to concepts in a way I never have before. Has anyone ever tried to teach algebra and higher level math concepts this way?

I suspect if back in high school and college, math classes had geared machines I could touch and turn a crank on to see the "math work", maybe my life would have been different. I basically dropped out of college due to falling behind in high school on algebra fundamentals and never being able to catch up in college. When I found I loved computers in the college's BASIC 101 class, yet found any access to computers beyond that class requiring a transfer to the math dept (this being the early 80s), and not being able to pass the prereq classes for that transfer, I dropped out. Strangely, I immediately bought an 8-bit computer with 4K of RAM and became an entirely self-taught programmer (which ended up working out very well for me in the end), but what might have been...

my head canon is that in the Dune universe, their response to the Butlerian Jihad was to develop better and better mechanical computers; specifically, via miniaturization, down to the nanometer level. It doesn't quite work for everything (Holtzmann shields are entirely analog?) but it works well enough to map most objects to a viable analog controller made of nanometer-scale analog computers.

The ban on thinking machines in Dune has nothing to do with the mechanics by which those machines work.

For all we know (I'm ignoring Brian Herbert's fanfiction here) the predominant type of computing at the time was mechanical. In any case, it wouldn't have mattered.

Can't have a military training film or newsreel without march cadence intro music. It inherently tells you to "sit still, pay attention, and listen." This means you!

Bagpipes are the same thing. Nowadays, nothing seems official unless it starts or ends with bagpipes.

Mechanical Computer – Basic Mechanisms in Fire Control Computers (1953) [video] - https://news.ycombinator.com/item?id=29471331 - Dec 2021 (12 comments)

Basic Mechanisms In Fire Control Computers (1953) [video] - https://news.ycombinator.com/item?id=7831923 - June 2014 (6 comments)

"Obviously, computer accuracy depends on the quality of the information it receives".

So true.

Low quality received, poor accuracy out.

Made me look up the origin of 'garbage in garbage out. Interesting that GIGO descends from LIFO and FIFO.

More info: https://wordhistories.net/2022/12/05/garbage-in-garbage-out/

https://www.linkedin.com/pulse/you-what-eat-gigo-gastao-de-f...

Why not do some math to fix it?

https://xkcd.com/2494/

That made me think of a quote from Charles Babbage, arguably the inventor of the mechanical computer. I wonder if it was added intentionally as a reference:

> On two occasions I have been asked, — "Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?" In one case a member of the Upper, and in the other a member of the Lower, House put this question. I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question.

– Charles Babbage in Passages from the Life of a Philosopher (1864)

People might also be interested in this 1944's Bureau of Ordnance's 433-pages pamphlet: Basic Fire Control Mechanisms <https://maritime.org/doc/op1140/index.php> (PDF).

When my great grandfather was drafted in WWI from the chemistry department at Berkeley to Annapolis, they put him on a ship as an ensign doing targeting.

Thought it was very interesting to see the precursors of modern computers and how they achieved the various mathematical functions mechanically

And fascinating too that, unlike digital computers where operations take clock cycles, calculations in an analog computer are effectively instantaneous.

Backlash means there is delay in analog computers that is generally worse than in digital. However the calculations you perform on analog computers are generally much simpler and so you don't notice the lag.

edit: I should point out that some calculations that are trivial on analog computers and difficult on digital and so analog may have less lag on some specific calculations. However in general it is safe to say digital is faster overall even though in the real world you will find many examples where analog is faster.

It's better than that. As an analog computer, both the inputs and outputs are _continuous_. So it's possible to get down to very small deltas that are only limited by the internal precision of the system itself, and the precision of measuring those inputs and outputs.

At the same time, precision is dictated by machining tolerances for the instruments in the calculation chain, as well as any mechanical forces in play at the time. Even the temperature of parts can change the dimensions of parts which can introduce error. And then there's the accumulation of error across a deep enough mechanical "pipeline".

What really gets me is how there is this tradeoff between analog and digital computers. Digital systems don't have precision errors from miss-shaped parts, but instead opt for errors in quantization (digitization) instead.

The neat part is that it's almost instantaneous, but not quite.

How electricity flows through analog circuits and chooses the right path is another fascinating subject. Seeing how it actually works "in action" seems to glimpse some insights into ultra-fast computing paradigms: not just computing with analog circuits, but also structuring computation like circuits.

https://www.youtube.com/watch?v=2AXv49dDQJw

Not instantaneous on any scale a digital system would regard as important. You can't turn a shaft very far in a nanosecond, and you are in general limited by the inertia of the mechanical system as well as quantities such as bearing overheating, lubricant viscosity, the maximum force that can be applied through any particular component, and so on.

The Thomson (also known as Lord Kelvin of degrees K fame) tide predicting machine takes us back to the late 1800s.

https://en.wikipedia.org/wiki/Tide-predicting_machine

One implementation of it was a notable part of WWII:

> They came to be regarded as of military strategic importance during World War I, and again during the Second World War, when the US No.2 Tide Predicting Machine, described below, was classified, along with the data that it produced, and used to predict tides for the D-Day Normandy landings and all the island landings in the Pacific War.

https://en.wikipedia.org/wiki/Tide-Predicting_Machine_No._2

From Veritasium : The Most Powerful Computers You've Never Heard Of - the tide calculator plays a prominent part of the video. https://youtu.be/IgF3OX8nT0w (the next video is also in the same topic - Future Computers Will Be Radically Different https://youtu.be/GVsUOuSjvcg and that gets into more modern implementations and uses - https://the-analog-thing.org is the device shown in the video).

What's amazing is some of these fire-control systems using up to 15kW to keep all the motors and mechanicals moving!

On the topic of analog computers, I recently decided to explore the topic a bit and built something similar to "Tennis for Two" (one of the first video games) on a single breadboard using op amps and relays: https://blog.qiqitori.com/2024/08/implementing-tennis-for-tw...

The videos on WW2 bomber gun system and bombing computer are also very fun.

Too lazy to find specific videos, but this entire channel is A+

https://www.youtube.com/@WWIIUSBombers/search?query=computer

This one about the battleship New Jersey as well: https://youtube.com/watch?v=kDOFBGIf6Uo, which has a more modern version of the https://en.wikipedia.org/wiki/Mark_I_Fire_Control_Computer

I especially like the section on differential gears, demonstrating their use as computing units: (timestamped link) https://www.youtube.com/watch?v=gwf5mAlI7Ug&t=771s

Love the DHARMA Initiative feel of it!

Excellent, particularly the differential computing aspect. Thanks for posting this.

I wish I grew up with educational videos like these. Simple, to the point, foundational videos that teach complicated topics from building blocks. I love the practical demonstrations. If I saw these as a child, I would have certainly considered majoring in engineering.

This made me think of engines as computers- the crank shaft connected to the timing belt goes up to the camshafts to instantly calculate the positions of the valves.

Likewise, an automatic transmission is a hydraulic computer.

50 years ago that was true. Sometime ago though (I don't know when, but I'd guess starting in the 1990s) they changed to electronic computers. Using electronics makes some things simpler and puts the complex parts in standard hardware (a CPU is much more complex but it isn't custom designed for you), or software (easy to change if you get it wrong.

For the fuel injection and ignition (spark) timing yes, but the camshafts to open and close the valves are still driven by a gear, belt or chain. Even variable valve timing is mostly controled by mechanical or hydraulic means, though I'm guessing some electronics may be involved.

FreeValve

Context? What is FreeValve?

It replaces cams with electronic actuators

This is about transmissions.

Upthread mentioned camshafts and valves, guess my reply is mostly to that.

Yeah, but the electronic control in 4 speeds was basically replicating the mechanical control of the previous generation. So it was more of an incremental improvement over old tech.

Whereas modern 6+ speed transmissions are very different in design and control.

This is part of the reason why four speed autos stayed in use for so damn long. You can automatically shift a four speed transmission with a pair of solenoids that turn on/off based on the input values from a couple of basic sensors.

The solenoids control which pair of clutches in the transmission engage, which in turn, determines the gear the transmission is in.

Driveability wise, they were awful, and their overall efficiency was pretty bad. But the fact that it could automatically select the correct gear out of three or four with just one user input (throttle) is still marvelous.

They could also handle insane amounts of power for the era. The GM 3L series came out in 1964 and was the transmission people would reach for when they were putting WWII era plane engines into crazy automobiles.

The speedometer on most cars is a kilometers - miles - kilometers calculator.

There used to be a real art to make informational videos like this.

Here is one on punchard machines:

https://www.youtube.com/watch?v=etu-cH-nkIA

Now a days we just deploy tech all YOLO style.

There's a copyright notice at the start that says this film is owned by Periscope films. If this video was actually created by the US government, then it should be in the public domain.

Longer version of the video without the annoying watermark and timestamp https://youtube.com/watch?v=s1i-dnAH9Y4

I absolutely adore this series of videos! Analog/mechanical computing is a fascinating field that is often ignored.

Also the pedagogical style of these videos is fantastic, simple, to the point, with no unnecessary distractions. It's hard to find this level of quality in the current 'click and subscribe' universe!

Happy to see this pop on HN :)

the current 'click and subscribe' universe!

The audience for this film was heavily advertised to, in order to get them to subscribe:

https://fr.wikipedia.org/wiki/Fichier:Untitled_%282%29World_...

And if that didn't work, many were simply coerced into it by the state. You don't need to pester a captive audience to smash the like button.

A similarly interesting video in this pedagogical style is 'Around The Corner - How Differential Steering Works (1937)': https://www.youtube.com/watch?v=yYAw79386WI

Another archaic technology is magnetic amplifiers. These were more used in Germany (in the Kriegsmarine and also in the V-2), but got some more play in the US immediately after the war, before being largely supplanted by transistors.

The idea here was to use magnetic saturation to modulate the behavior of a transformer, allowing a small control current to modulate larger AC currents.

https://en.wikipedia.org/wiki/Magnetic_amplifier

Can anyone find parts 2-4? This seems to just be part of 1!

Here you go:

https://www.youtube.com/watch?v=T_xhMykK5Hw&t=1s

someone should build a very precise "lut" with mems and this tech. would be pretty hard tho

Modern educational videos/films feel lower quality (in terms of content) even with all the modern tech at their disposal.

Better technology doesn't seem to improve education. The quality of the content is 99% the skill of the teacher.

Sometimes I feel like if we had a video like this for every concept we’d be in Star Trek utopia by now.

Domain experts and instructional designers working together, in close proximity, in both time and space, produce the best educational content in my opinion. Without iteration and feedback loops between these groups we end up with the shallow content that is so prevalent in the e-learning industry.

> Domain experts and instructional designers working together, in close proximity

I dream of an online community encompassing science researchers, instructional designers and education researchers, software developers, and teachers. So "my students are struggling with" -> "the underlying idea is" -> "maybe represent that as" -> "here's a strawman web interactive" -> "tried it this afternoon, mostly worked, except for" in tight iterative churns.

Agreed. Check out all the popular historical war documentaries on YouTube. They are labeled "simplified, learn in 10 minutes etc", also use childlike cartoons. Never any interviews with real world experts.

It's almost like the concept of making technology easy enough for a child to use has spread to other areas.

I've seen a few of these old instructional videos.

In addition to the content itself, I'm always very amazed by the fact they can produce these videos without computers!

The difficulty of editing in the pre-computer days may have helped, in that they probably went to a great deal of effort to fully plan out the content instead of YOLO'ing "we'll fix it in post".

Having worked professionally through the evolution video production from the early 80s to the present day, variously as an editor, videographer director and producer, then switching to making digital video production tools (both live and post) as a programmer, product manager, etc it's hard for me to watch anything and not think about how it was made along with pondering the tooling and workflow.

So, like you, I watched the film (as it was certainly produced on 16mm film) and was surprised by the quality of the graphics, titles and animation. Even the shooting and editing was remarkably good for what's obviously an industrial-grade training film produced on an assembly line. I was especially taken by the fidelity of the full screen title slides featuring soft-edged drop shadows. When I started out in video, the first place that hired me was a tiny hole-in-the-wall studio that produced corporate and industrial sales, marketing and training videos for mid-sized clients on 3/4 inch U-Matic tape. And they still laid out titles by hand a line at a time with a manual Letraset-type machine. The titles we did in the mid-80s didn't look as nice as what these guys were doing in 1953!

Reply on news.ycombinator.com