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Old 07-13-2018, 12:04 AM
Wesley Clark Wesley Clark is offline
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How do you design something as complex as a submarine

I'm watching Das Boot for the first time and am impressed by how complex the submarine is. And I'm sure there are other feats of engineering that are much more complex.

So I'm wondering, how do engineers know down to the most minute details how to build something that large, complex and interdependent? Can you just tell a team of 5,000 engineers 'design a submarine' and then it will be designed in a way that works well, down to the most minor details?

How do they even know if the parts will all work together, or will withstand real world testing? Do they just build a model, then fix the kinks, then do that again and again until they have a working model? Or do they just assume everything will work together? Or do they just tweak an existing model?

Does the engineering team get broken up into various groups and subgroups? How would the teams be broken up?

I have no background in engineering, so I don't know how any of this works.
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Old 07-13-2018, 12:13 AM
Lamoral Lamoral is offline
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This is a damn good question; I, too, would like to know the answer. All I can say with regards to submarines is that I was inside the captured Nazi submarine that's at the Chicago Museum of Science and Industry, and I learned there that being in a Nazi submarine was, like most things associated with Nazis, horrible.

They had something like an 85% mortality rate.
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Old 07-13-2018, 02:13 AM
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I'm not a physical objects style engineer, but I do note that most buildings simply reserve a space and expose some tubes for things like the washing machine, dish washer, etc. when the building is under construction. They don't need to know exactly what machine nor exactly what size machine will go there, nor do they need to know anything at all about how it works internally.

My presumption would be that they do something similar, where there's a lead engineer who gets some basic dimensions for each thing and the I/O (water, fuel, electricity, etc.) that's necessary for it and does up all of his plans with the expectation of a perfect cuboid, slightly large than the dimensions he was given, that can accept cables and piping from any direction. The lead engineer will have some basic parameters like that overall, people need to be able to move around the ship and the whole thing can't weigh more than X, can't supply more than Y water, Z fuel, nor W electricity in total, and so he'll work with all of the available cuboids he was given, see if it all fits under some arrangement, and if not then he'll need to call around to different makers and ask them to custom make something.

On the maker's side, they won't know anything at all about the submarine, they just know that they were told to make their widget no larger than some specific dimensions and have an I/O of whatever. And while they're building their widget, they'll do the same thing. There will be a lead engineer who knows what all of the major subcomponents are, maybe takes some off the shelf parts and orders others to be designed from scratch by his minions. He'll give them specific dimensions that they have to hit, and it's on them to make sure that they hit the requirements. If somehow they can't, then it will have to go back up to the lead designer and he might have to rejigger everything and see if any other components are coming in smaller than originally expected, etc.

Back in the 40s, following that step maybe they would have gotten a model maker to actually go and craft little versions of everything (so they don't have to treat it all as cuboids) so that they could glue it all together in their model submarine shell and see if it all fits nicely and if there's any spare room for more goodies. These days, they'd probably ask the maker to send them files for some sort of 3D program (and probably would have skipped the initial step with cuboids).

But even then, assembly (particularly for your first version of the submarine) is going to be a major undertaking because you're suddenly going to find out that measurements were wrong, that the position of the I/O ports are all in completely horrible locations, that a device gets super hot and needs an extra 4 inches of insulation around it, that some machine is ridiculously failure prone, etc. They'll have to build custom stands and mounting points for everything, figure out how to feed wire and tubing throughout the ship and where to install maintenance access points, etc.; they'll need to request that some stuff be replaced with different hardware; and they might end up performing some jury-rigged modifications on the hardware they got.

Through all of this, they'll probably end up developing more detailed designs, they'll build sub-blueprints for small parts for installation - like mounts for different parts - and so on so that the next time they build the ship they can do so more quickly. But likely each ship will end up slightly different due to assembly-time problem-solving.

But so overall the strategy is: Visualize a bunch of cubes. Find things that fit in those cubes or order something that will. Repeat as necessary for subcubes, sub-subcubes, etc.
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Old 07-13-2018, 02:24 AM
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The biggest issue with a sub is most of the guts have to be there before you put it together, or they fit through a hatch 30" inch in diameter.
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Old 07-13-2018, 02:48 AM
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To put Sage Rat's excellent description in a word, it is modularity and hierarchy. And specialization. I don't know about submarines but I do know about the design of billion transistor microprocessors. You start at the top level with modules like processors, memories, cache controllers, I/O controllers, etc. You have teams designing each one to a spec. You have other specialized teams routing signals between these and making sure the global timing works. Then you have other teams working on verification and manufacturing test. It might take hundreds of people, but it is not chaotic and everyone knows what he or she is doing.

I'm sure submarines, like microprocessors, are not all that different from the ones that came before, so they start with a known template and evolve the design from there.
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Old 07-13-2018, 03:07 AM
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You take an earlier model of submarine and improve it. Most technology is a result of evolution, not intelligent design.
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Old 07-13-2018, 03:46 AM
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Originally Posted by Alessan View Post
You take an earlier model of submarine and improve it. Most technology is a result of evolution, not intelligent design.
This.

The designers are not starting off with a blank slate. They are starting off with the detailed technical knowledge and specifications of previous submarines, and the records of how they performed under real life conditions. Then they are making incremental improvements.

Usually the lead engineers would have many years, maybe decades, of experience in submarine design, and the manufacturers and builders likewise would have plenty of experience in building earlier submarines.
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Old 07-13-2018, 04:25 AM
Chisquirrel Chisquirrel is offline
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To put Sage Rat's excellent description in a word, it is modularity and hierarchy. And specialization. I don't know about submarines but I do know about the design of billion transistor microprocessors. You start at the top level with modules like processors, memories, cache controllers, I/O controllers, etc. You have teams designing each one to a spec. You have other specialized teams routing signals between these and making sure the global timing works. Then you have other teams working on verification and manufacturing test. It might take hundreds of people, but it is not chaotic and everyone knows what he or she is doing.

I'm sure submarines, like microprocessors, are not all that different from the ones that came before, so they start with a known template and evolve the design from there.
This. Start with the big picture - what you want, and what you want it to do. Figure out what systems you need to accomplish those goals. Break everything down bit by bit, until you have individual parts. Throw that design document at an engineer or five and say, "GO!"
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Old 07-13-2018, 10:23 AM
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An engineering degree gets you part of the way. You spend four+ years learning the basics of machine design, fluid mechanics, thermodynamics, heat transfer, metallurgy, and so on. Or you go for a couple more years to get a master's degree in a more specialized area. Or you go for several more years to get a Ph.D. in a very specialized area.

"Institutional knowledge" is another part of the puzzle, and comes with experience. Some of that is in the heads of the engineers. A senior engineer from Ford will know from experience roughly how far apart to place the attachment points for a door panel, dashboard, or headliner so as to minimize buzz, squeak and rattle, something that submarine designers won't know. He'll know from his engineering classes that a submarine propeller blade will utilize a "wing" cross section to produce thrust, but he won't know exactly what shape is most efficient, least noisy, or least prone to cavitation under various conditions - something that experienced submarine designers will know.

Some of that institutional knowledge is proprietary, i.e. not all submarine designers will know it. If your company has invented an alloy that's particularly resistant to seawater corrosion, or developed a propeller that's ultra-quiet, or a novel welding process that makes explosion-resistant hull joints, you're not going to share that with your competitors.

Some of it is incremental development: you take one of your submarine designs that worked pretty good in the past, and you improve on it.

Some of it is independent design and testing. The components of a submarine are not 100% independent, so you can parcel out the work to separate design teams and bring it all together at the end. You can find examples of this in other industries. Here, for example, is a lab test of the Airbus A380's landing gear: the wheels are are spun up to touchdown speed, and the whole landing gear is slammed to the ground at "hard landing" vertical speed, with all of the momentum on it that a real A380 would have during a hard landing. Likewise, here's a laboratory brake test, in which they simulate braking the A380 to a stop in an overweight condition with no reverse thrust. How does the brake behave? Does it disintegrate? Does it catch fire? If so, does the fire spread? There will be a full-up aircraft test like this later on, but you don't want that to be the first time you've tried using the brakes; it's possible to gain confidence first with test cell work like this. There's a lot of the same sort of thing you can do for a submarine.

And no matter what you make, there's a lot of testing/redesign iteration along the way. Decades ago you'd make scale models or full-sized prototypes based on your engineering degree and institutional knowledge, test them, and then refine your design based on the test results. This cycle is much faster and cheaper these days thanks to computers. You can design a part or assembly on a computer, and then use finite element analysis to assess various performance aspects. Is it strong enough? Are there stress concentrations that need to be alleviated with a little more/less material in certain spots? Are the heat transfer properties adequate/optimized? More/thinner/thicker cooling fins needed? Problematic vibrations that might be fixed with more/less mass here and there? Is it managing air/water flow/pressure as needed? You can do all of this in the computer and come up with a design that's very likely to be very good the first time you make it.

Computers are also great for coordinating the work of all the subgroups. A central archive can hold the master plan for the submarine that hosts all of the subsystems being designed by the semi-independent groups, so that everyone can see how the different subsystems are going to mesh in the final assembly and work in a cooperative manner.

And in the end, you make your full-scale, fully-assembled prototype, and you test it as incrementally as you can. At this point it's unlikely that you'd have to scrap the entire design, but the computer analysis is never perfect; you'll always find little things that need adjustment. For airplanes, you start with a high-speed taxi test, in which the plane doesn't even leave the ground. Then you take off for a very basic flight, never even raising the landing gear. You build confidence in the plane as you put it through harsher and harsher tests (e.g. a high-speed flutter test. Similar testing happens with submarines and other large machines.
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Old 07-13-2018, 11:44 AM
msmith537 msmith537 is offline
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I have a degree in structural engineering, but never really practiced, so that that as you will.

As others pointed out, a lot of it is breaking it down into systems and subsystems and hierarchies. For example, a submarine is essentially just a big pressure vessel. Similar to a tank that one might use to store propane or an aerosol can. Except the pressure is on the outside. There are pretty well established mathematical formulas for calculating how thick a material needs to be to support such and such pressure pushing in on it for a vessel of so and so size.

Of course the trick is you can't cast a big U-boat as one monolithic entity. And even if you could, you would still need holes for hatches, screws, periscope, exhaust, torpedoes, venting for ballast and whatnot. So now engineers break down these different systems, figuring out the requirements for each.

A whole lot of project planning and management goes into it as well. That is to say, figuring out the dependencies of tasks and sequence for which the can be addressed.


Also note, that as technology matures in any particular area, they don't need to redesign everything from scratch. Like when they design and build a new airplane, most of the time, they are designing around existing engines and the people who design engines design them for fairly standardized engine housings.







There are actually a fair number of videogames like Kerbal Space Program, Factorio, Oxygen Not Included and Space Engineers that give you a sense of how to design and build complex systems. Often what makes them fun is when a weakness is exposed causing a "cascading failure". Like when my outhouse breaks down in ONI and soon my base is drowning in it's own vomit.

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Old 07-13-2018, 02:06 PM
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Each small team of engineers works on a small part of a submarine.

Each new submarine is a modification of a submarine previously built.
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Old 07-13-2018, 02:17 PM
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You take an earlier model of submarine and improve it. Most technology is a result of evolution, not intelligent design.
And proof of this is the set of odd features found in any nth generation design, which were good ideas (or maybe bad ones) when added originally and which have been kept in because taking them out would be risky and might delay the project.
Just like the odd features found in most evolved plants and animals.
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Old 07-13-2018, 02:41 PM
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Each small team of engineers works on a small part of a submarine.

Each new submarine is a modification of a submarine previously built.
And other teams coordinate stuff. Also, some blocks are designed already: you most likely don't need to design... toilets, bunks or GPSs, just pick which ones to use.

I was a tiny part in a project to design a new motor. The first few years were going to be spent in design, make, redesign, make again... and this had to be coordinated through multiple factories in several countries. The design team was a handful of people, all sitting in the same room, but they had to coordinate among themselves (if you change one piece, you have to check the designs of at least all the pieces it's in contact with) and with the factory teams (can you do it, if I change this detail? How long will it take to get the machines adapted?). That motor was eventually, hopefully, going to be slotted into place in bigger designs he way one slots dishwashers, but that requires the designers for the slotable item to take sizing standards and connectors into account.
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Old 07-13-2018, 03:19 PM
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Former submarine officer here. After I graduated from college with an engineering degree, the U.S. Navy spent 18 months training me just to safely operate a nuclear-powered submarine (much less design anything). I can't tell you how many times I was awe-struck at the ingenious engineering that was evident in the design.

As others have indicated, you have engineering design teams that specialize on each small part of the sub, and they build on previous designs.

Some submarine design improvements involve a great deal more effort, such as when the first nuclear power plants were designed for submarines. The Navy (and its contractors) tried out a variety of competing designs before settling on a standard, which has since been modified more incrementally.

This model for building on previous designs is one reason why the U.S. Navy does not want to ever stop building nuclear submarines. Otherwise all of the expertise and institutional knowledge would be lost as people retire (and pass away). This is also why the Navy has supported two shipyards capable of building nuclear submarines: General Dynamics Electric Boat in Groton, CT and Newport News Shipbuilding in Virginia.

On a related note, while submarines are complicated, they are not nearly as complicated as manned spacecraft and rockets. After the Apollo program ended, we allowed much of the associated expertise and institutional knowledge to wither away. This is one reason why there haven't been any manned missions beyond low Earth orbit (LEO) since then. I've heard it said that we couldn't send a man to the moon right now even if we had the will and desire to do so. After nearly 50 years, much of that knowledge and expertise would have to be recreated nearly from scratch.
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Old 07-13-2018, 03:21 PM
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http://www.doerry.org/norbert/refere..._Section_A.pdf
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Old 07-13-2018, 03:43 PM
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As others have said, hierarchy and specialization are key.

There are tradeoffs here, though. As Sage Rat pointed out, for something like a building, most of the components are left unspecified. Standard electrical sockets are put in, plumbing is routed, but beyond that there is flexibility in where things are put. Buildings have a great deal of margin available--they are massively overbuilt, and so not very sensitive to moving weight around or other variations.

On the other end of the spectrum, we have rockets, which are exquisitely sensitive to mass, power, temperature, vibration, and so on. Virtually every component can, potentially, cause a failure in the entire system. This makes rockets very expensive--you can't just buy an off-the-shelf whatever and plug it in; it has to be qualified for use and integrated into the full system. Rockets have almost no margin to them; if a particular component is twice the mass that it should have been, it probably just won't work. It has to be redesigned.

Somewhere in the middle we have things like submarines and automobiles. They are not as free-form as buildings, but they have a decent amount of leeway when it comes to mass and other things. If the engine produces 10% less power than it should; well, that's unfortunate but it probably means the vehicle is just a little bit slower than we'd like. Contrast with a rocket where if the engines underperform by 10%, then it doesn't make orbit and has to be destroyed.

The more margin you have, the more flexibility you have in the hierarchy and the cheaper it gets, because it's much easier to make tradeoffs. Design variations have only local effects. But as margin decreases, the hierarchy becomes rigid, up to the point where a single variation anywhere in the system affects the entire system. Design becomes very expensive.
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Old 07-13-2018, 03:47 PM
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And other teams coordinate stuff. Also, some blocks are designed already: you most likely don't need to design... toilets, bunks or GPSs, just pick which ones to use.
The Navy actually uses relatively few commercial off-the-shelf items on submarines (with some exceptions, like computer laptops).

To discuss your three specific examples:

Submarine toilets are connected to sanitary holding tanks that can be pressurized to overcome the surrounding sea pressure to empty the tanks (while far out to sea). The toilets have a stainless steel ball valve at the drain that can withstand this pressure. The toilets themselves are also made of stainless steel (as are the sinks and showers). Porcelain doesn't work all that well in a vessel that might take battle damage from exploding depth charges.

Similarly, with the possible exception of prisons, nobody would have a need for a bunk with as little space as on a submarine.

Finally, GPS units utilized by the military are military hardware, not civilian models. The Global Positioning System (GPS) (originally the Navstar GPS) is a military satellite system that is owned and operated by the U.S. Air Force. Should the U.S. government choose to do so, it can selectively deny access to the system or degrade the signal at any time. An encrypted signal can be maintained for U.S. military units and our allies. You need a military-grade GPS unit to be able to utilize the GPS network in such a scenario.

Besides that, you want a GPS unit that can work reliably in a submarine environment, and which can be utilized with receivers mounted on submarine masts and/or antennas.

This specialized equipment is one reason why military hardware is so expensive.
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Old 07-13-2018, 04:30 PM
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And other teams coordinate stuff. Also, some blocks are designed already: you most likely don't need to design... toilets, bunks or GPSs, just pick which ones to use.

I was a tiny part in a project to design a new motor. The first few years were going to be spent in design, make, redesign, make again... and this had to be coordinated through multiple factories in several countries. The design team was a handful of people, all sitting in the same room, but they had to coordinate among themselves (if you change one piece, you have to check the designs of at least all the pieces it's in contact with) and with the factory teams (can you do it, if I change this detail? How long will it take to get the machines adapted?). That motor was eventually, hopefully, going to be slotted into place in bigger designs he way one slots dishwashers, but that requires the designers for the slotable item to take sizing standards and connectors into account.
Definitely. Even though a submarine has millions of details, most of them are in blocks designed by generations of engineers before.
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Old 07-13-2018, 06:43 PM
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The Navy actually uses relatively few commercial off-the-shelf items on submarines (with some exceptions, like computer laptops).

To discuss your three specific examples:

Submarine toilets are connected to sanitary holding tanks that can be pressurized to overcome the surrounding sea pressure to empty the tanks (while far out to sea). The toilets have a stainless steel ball valve at the drain that can withstand this pressure. The toilets themselves are also made of stainless steel (as are the sinks and showers). Porcelain doesn't work all that well in a vessel that might take battle damage from exploding depth charges.

Similarly, with the possible exception of prisons, nobody would have a need for a bunk with as little space as on a submarine.

Finally, GPS units utilized by the military are military hardware, not civilian models. The Global Positioning System (GPS) (originally the Navstar GPS) is a military satellite system that is owned and operated by the U.S. Air Force. Should the U.S. government choose to do so, it can selectively deny access to the system or degrade the signal at any time. An encrypted signal can be maintained for U.S. military units and our allies. You need a military-grade GPS unit to be able to utilize the GPS network in such a scenario.

Besides that, you want a GPS unit that can work reliably in a submarine environment, and which can be utilized with receivers mounted on submarine masts and/or antennas.

This specialized equipment is one reason why military hardware is so expensive.
These might not be commercial to civilians, but that doesn't mean that I need to go request a fresh redesign of a GPS system just because I'm building a new submarine design. There is, presumably, a catalogue of "off-the-shelf" items that exists solely among the military world.
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Old 07-13-2018, 07:27 PM
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These might not be commercial to civilians, but that doesn't mean that I need to go request a fresh redesign of a GPS system just because I'm building a new submarine design. There is, presumably, a catalogue of "off-the-shelf" items that exists solely among the military world.
New submarine classes come around so infrequently these days (like once a generation) that virtually every integrated system on a new class of submarine is indeed redesigned.

But again, you are building on previous designs. While a Los Angeles-class submarine has an S8G reactor (i.e. 8th generation reactor designed by GE), the Virginia-class subs have an S9G reactor. It's not like you're starting from ground zero.

Also, many systems are upgraded along the way, especially with the electronics (including software upgrades), as well as systems that can easily be swapped out, such as towed-array sonars and weapons.

For example, the Los Angeles-class submarines started out with Mark 48 torpedoes, then were upgraded to carry Mark 48 ADCAP torpedoes. Virginia-class subs also currently carry Mark 48 ADCAP torpedoes. These torpedoes are themselves upgraded on a continual basis.
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Old 07-13-2018, 07:51 PM
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This is a damn good question; I, too, would like to know the answer. All I can say with regards to submarines is that I was inside the captured Nazi submarine that's at the Chicago Museum of Science and Industry, and I learned there that being in a Nazi submarine was, like most things associated with Nazis, horrible.

They had something like an 85% mortality rate.
Hey, 85% is not that bad, considering that mortality rate for humans in general is 100%!

(But yeah, I get your point. And never, ever would I dare to go for a dive in one of those!)
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Old 07-14-2018, 01:25 PM
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How does a general decide what each soldier will do? He doesn't. How does a city planner decide how each room/passage in the city will be arranged? He doesn't.

It does pose the question of how many subunits, on average, can each level handle efficiently. In the military, it's usually 3-5 subunits per unit so 3-5 squads per platoon, 3-5 platoons per company, 3-5 companies per battalion, 3-5 battalions per regiment then division then corps. The 3-5 trend may be because the military often has to take fast decisions un seriously suboptimal situations.

In IC design or programming, how many subsystems is each decisional level typically expected to handle? Is it mainly related to the limits of working memory?
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Old 07-14-2018, 02:23 PM
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These might not be commercial to civilians, but that doesn't mean that I need to go request a fresh redesign of a GPS system just because I'm building a new submarine design. There is, presumably, a catalogue of "off-the-shelf" items that exists solely among the military world.
And just to get the terminology straight, COTS in the defense world means specifically that the parts are commercially available. In semiconductors, at least. COTS stuff is often far ahead of military specific stuff, though there might be some requirements for military stuff that requires special design. Still, the impression I got from the defense guys on my committee was that there was a push to use COTS components wherever possible for cost reasons.
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Old 07-14-2018, 06:48 PM
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On a related note, while submarines are complicated, they are not nearly as complicated as manned spacecraft and rockets. After the Apollo program ended, we allowed much of the associated expertise and institutional knowledge to wither away. This is one reason why there haven't been any manned missions beyond low Earth orbit (LEO) since then. I've heard it said that we couldn't send a man to the moon right now even if we had the will and desire to do so. After nearly 50 years, much of that knowledge and expertise would have to be recreated nearly from scratch.
That's not true at all; what did get lost is a lot of the knowledge involved in building Saturn V rockets.

That's about it though; rocket engine design and manufacturing continued apace; the SSMEs were a post-Apollo design, as are the RS-68 engines that power the Delta IV, and a few others. Other designs have been continually upgraded- the RS-10 used in the Atlas IV upper stages, and several others as well.

Even the Saturn V engines have been modernized- the J-2X is a modern version of the J-2 from the upper stages, and there has been a lot of work done on a F-1B modernized and simplified version of the F-1 first-stage engine.

A lot of other stuff has also been continuously improved since Apollo- spacesuits, procedures for EVA, etc... were refined during the Shuttle era. Same with electronics and materials.

The only thing lacking is a heavy booster, and NASA will soon have that with the Space Launch System, which is slated to be roughly equal (either slightly more or slightly less) to the Saturn V in terms of lift capacity, and from 133% to nearly 200% the capacity of a Falcon Heavy.
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Old 07-15-2018, 01:27 AM
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That's not true at all; what did get lost is a lot of the knowledge involved in building Saturn V rockets.

That's about it though; rocket engine design and manufacturing continued apace; the SSMEs were a post-Apollo design, as are the RS-68 engines that power the Delta IV, and a few others. Other designs have been continually upgraded- the RS-10 used in the Atlas IV upper stages, and several others as well.

Even the Saturn V engines have been modernized- the J-2X is a modern version of the J-2 from the upper stages, and there has been a lot of work done on a F-1B modernized and simplified version of the F-1 first-stage engine.

A lot of other stuff has also been continuously improved since Apollo- spacesuits, procedures for EVA, etc... were refined during the Shuttle era. Same with electronics and materials.

The only thing lacking is a heavy booster, and NASA will soon have that with the Space Launch System, which is slated to be roughly equal (either slightly more or slightly less) to the Saturn V in terms of lift capacity, and from 133% to nearly 200% the capacity of a Falcon Heavy.
So in other words, because we stopped building Saturn V rockets some 50 years ago, we've had to design a completely different heavy launch system to replace it (which is apparently derived from the launch system used for the Shuttle).

In any event, the Apollo program was comprised of more than just the launch system. It also included the Apollo Command Module, Service Module, and Lunar Module. To the best of my knowledge, there is no currently operational equivalent for any of these. More to the point, everyone who worked on the design of these modules has either retired or died.

In short, how long would it take to put a man on the moon, starting from today? How much of this new program would have to be designed essentially from scratch? (This is a serious question, not a rhetorical one. I am genuinely curious.)
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Old 07-15-2018, 02:40 AM
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In short, how long would it take to put a man on the moon, starting from today? How much of this new program would have to be designed essentially from scratch? (This is a serious question, not a rhetorical one. I am genuinely curious.)
It took about 8 years last time. I don't see why it should take any longer now, assuming we're willing to invest the same amount of money.
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Old 07-15-2018, 07:49 AM
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Engineering and design for any large project will have various levels of leadership and coordination. If it's well-managed, you'll have a bunch of teams working together and someone on charge to make the hard decisions, because engineering is, to a great degree, the science of compromise. There are space, weight, time, budget, mission, maintenance, and operational constraints, among others. You can come up with the greatest design ever for a system, but if it won't fit or if it costs too much or if it causes interference with another system, something's gotta give.

This is true for submarines, aircraft, amusement park rides, kitchen appliances... well, you get the idea. And it does help when you are designing a newer version of something that already exists, but the same applies to brand-new, never-been-done-before designs. Big task broken down as necessary to smaller tasks, choreographed to come together on time and on budget... theoretically.
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Old 07-15-2018, 09:08 AM
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It took about 8 years last time. I don't see why it should take any longer now, assuming we're willing to invest the same amount of money.
It took somewhat longer than this, considering that the Apollo program was directly preceded by Projects Mercury and Gemini. However, I think it would be difficult to replicate the urgency of the project today, what with the race to the moon the first time against the Soviets.

In any event, what about the second question? For a repeat manned Moon program, how much of this new program would have to be designed essentially from scratch?
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Old 07-15-2018, 05:41 PM
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In short, how long would it take to put a man on the moon, starting from today? How much of this new program would have to be designed essentially from scratch? (This is a serious question, not a rhetorical one. I am genuinely curious.)
From today? About 5 years, considering that they started the work on the SLS and Orion capsule/service module in 2011, and are planning an Apollo 8 style circumnavigation of the moon in 2023- with as much as a 6 person crew.

A lot is being derived from scratch- the capsule, for example, but the SLS itself derives heavily from Shuttle components- SSME engines, SRBs very similar to the Shuttle, and the tankage is pretty similar to both the Shuttle and the Delta IV.

We didn't lose the knowledge to build rockets; we just QUIT building Saturn Vs because there wasn't a mission for them- we focused on the Shuttle.
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Old 07-15-2018, 05:53 PM
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Related to the OP, there's an unusual process that I've experienced in programming.

Computer programs, by necessity, start small. It's nice when they can do something even at that stage (as opposed to writing a giant program that only works when fully complete), so you find some bare-minimum thing to do and do that.

As the program grows, you find that certain things become difficult, so you go through a process of refactoring. Refactoring covers a lot of ground but usually it is about generalization--taking a specific implementation and turning it into common functionality. It's like having a hard-wired instrument on your submarine, getting annoyed that the wiring is getting convoluted, and then designing a common power and data plug system that all instruments can use. The wiring is simplified and you gain the flexibility of moving instruments around or designing new ones.

This often means growing the hierarchy--putting new (general) systems at the top that control (specific) systems at the bottom. The whole system is made modular; different subsystems don't have to know about each other. This goes on and on until you potentially have a very large program. Ideally, one that is divided into logical groups of functionality and not a bunch of "spaghetti code".

The strange part is this: it's easy to reach a level of complexity where you can't fit the whole program in your head at one time. Even though you wrote the entire thing, you can only understand a portion of it at any given moment. If it's well architected, you can easily move from component to component, quickly getting back up to speed--but this involves losing the details on another component.

It's weird, building something bigger than you are, but ultimately pretty rewarding. And it absolutely requires the kind of hierarchical design mentioned in this thread, because without it you could never focus on just one part of the design. It would only be possible to build things that entirely fit in your mental space, which is really a pretty small value.
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Old 07-15-2018, 05:57 PM
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It took somewhat longer than this, considering that the Apollo program was directly preceded by Projects Mercury and Gemini.
But the purpose of the Mercury and Gemini projects was to learn how to get manned craft into orbit, and to have them maneuver, navigate and link up with each other. We still do all that stuff today with the ISS.
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Old 07-15-2018, 08:24 PM
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It took about 8 years last time. I don't see why it should take any longer now, assuming we're willing to invest the same amount of money.
It took somewhat longer than this, considering that the Apollo program was directly preceded by Projects Mercury and Gemini.
...
From the first manned flight (Shepard in Mercury 3) to Apollo 11 was about 8 years.
https://nssdc.gsfc.nasa.gov/planetar...astronaut.html
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Old 07-15-2018, 09:23 PM
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From the first manned flight (Shepard in Mercury 3) to Apollo 11 was about 8 years.
https://nssdc.gsfc.nasa.gov/planetar...astronaut.html
From the beginning of Project Mercury in 1958 to the Moon landing was about 11 years.

What is the significance of the first manned flight? For what it's worth, we don't even have that capability at this time. Aren't U.S. astronauts currently hitching rides to and from the ISS in Russian Soyuz spacecraft?
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Old 07-15-2018, 10:05 PM
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P.S. In case it's gotten lost in all this back-and-forth, my original point was to compare the U.S. nuclear submarine program to the U.S. manned space program.

Since we first started building nuclear submarines in the 1950s, we've never stopped building them.

On the contrary, the U.S. manned space program seems to have had several starts and stops, from the Mercury/Gemini/Apollo/Skylab era to the Space Shuttle era to today. We currently have no man-capable heavy launch vehicle and no operational spacecraft, and this has been the case since the Shuttle was retired in 2011.

Lately, we seem to be getting into a habit of starting programs in one presidential administration, then canceling them in subsequent administrations, like the Constellation program. This seems like a complete waste of money and effort.

(BTW, I fully admit I am outside of my field of expertise here. I know a lot more about nuclear submarines than I do about our space program. My understanding of the latter is strictly that of a layperson.)
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Old 07-16-2018, 08:28 AM
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The Navy actually uses relatively few commercial off-the-shelf items on submarines (with some exceptions, like computer laptops).

To discuss your three specific examples:

Submarine toilets are connected to sanitary holding tanks that can be pressurized to overcome the surrounding sea pressure to empty the tanks (while far out to sea). The toilets have a stainless steel ball valve at the drain that can withstand this pressure. The toilets themselves are also made of stainless steel (as are the sinks and showers). Porcelain doesn't work all that well in a vessel that might take battle damage from exploding depth charges.
...
This helps to explain why military hardware is often mind-bogglingly expensive compared to its civilian equivalent.

Kohler manufactures and sells, among other things, toilets. The performance requirements in your master bathroom are pretty mundane; a failure in service is not likely to cause a death, the loss of a capital ship, or the loss of a battle/war. If their engineering team designs a new toilet and the prototypes behave well, they fabricate molds and packaging for it and get busy cranking them out by the tens of thousands for sale across the US and beyond. The cost of developing the toilet design, and the cost of the molds, gets amortized over all of those units, adding just a few dollars to the cost of each. In the end, Kohler can sell you a nice toilet for a few hundred bucks.

Newport News Shipbuilding manufactures and sells submarines, which have toilets installed in them. The performance requirements for these toilets are pretty stringent. If their engineering team designs a new toilet, as robby notes, it's got a lot to live up to; the combat environment is much harsher than your master bedroom, and a malfunction can can literally sink the ship, or divert the efforts of enough sailors to compromise the ship's combat effectiveness. So there's a lot more R&D that goes into designing it. When it comes time to actually making it, they're not going to make tens of thousands of them like Kohler; they might make a few dozen for the submarine they're working on. With so few units getting made it becomes harder to justify the upfront tooling costs for many of the processes, so you resort to more handwork (e.g. you've got a professional welder putting things together instead of a robotic welder). That means your per-unit cost will be much higher for those processes than Kohler's per-unit cost (although still less than it would be if you used more automation). And for some manufacturing processes, the best choice is still to use mass-production techniques (e.g. for forming a comfortably curved seat, they'll probably still machine the forms to stamp the seats out of flatstock) - so the upfront tooling cost is the same as for Kohler, but now you're amortizing those large costs over a few dozen units instead of tens of thousands of units. so the per-unit cost will be astronomically higher for those processes. If you broke out these toilets as a line item in the contract, it wouldn't surprise me if the cost were many thousands of dollars each.
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Old 07-16-2018, 11:40 AM
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P.S. In case it's gotten lost in all this back-and-forth, my original point was to compare the U.S. nuclear submarine program to the U.S. manned space program.

Since we first started building nuclear submarines in the 1950s, we've never stopped building them.

On the contrary, the U.S. manned space program seems to have had several starts and stops, from the Mercury/Gemini/Apollo/Skylab era to the Space Shuttle era to today. We currently have no man-capable heavy launch vehicle and no operational spacecraft, and this has been the case since the Shuttle was retired in 2011.
The thing is, they just haven't bothered to man-rate any of the existing rockets that could easily put men into orbit- the Falcon 9, the Delta IV series and the Atlas V series. Make no mistake though; rocket launching by NASA and the US hasn't stopped at all since 2011; we've launched a LOT of stuff.

My suspicion is that it's cheaper to just pay the Russians by the launch to put astronauts in the ISS via Soyuz rockets, than to go through the engineering trouble to man-rate the existing rockets.

So we haven't lost anything technology-wise- ULA and Grumman/Orbital ATK have been hard at it for years. And so has NASA; the SLS picked up where the Constellation project stopped.

The difference, I think between this and the nuclear submarine programs is that if you shut down Electric Boat for any significant amount of time, you lose ALL the tribal knowledge and experience and that sort of thing, since it's not like there's a big commercial submarine market out there. Basically you either keep building nuclear submarines at a steady, if slow pace, or you lose the ability to do it in a reasonable amount of time. Same goes for spacecraft, but the advantage is that there's a pretty solid commercial industry out there independent of NASA, so if NASA takes a break, none of that industry knowledge is lost in the interim.
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Old 07-16-2018, 12:02 PM
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I would add that if you broaden the question from how much effort it takes to design rockets or submarines, each of which poses very interesting challenges, the methods of constructing submarines and surface combatants is, IMHO, far, far more impressive than the production of a rocket.

Building a rocket is a really interesting process, but it is probably just what you expect: one group or company builds a really complex rocket engine, that is both very resilient and very precise; another group builds big fuel tanks of various sorts; another builds the metal sheath that it all goes in; and there's quite a bit of art and science in putting all the pieces together. It's pretty amazing to see something that weighs like 50,000 pounds (without fuel) come together like that.

But then, building something that displaces like 10,000 tons and contains a mind-boggling number of parts is just on another scale entirely. What's more, these boats aren't built like most people would think (lay the keel and build up until you're done). Basically, they are built in enormous sections that each weigh a gazillion pounds, moved to the shipyard, and fit together like Legos. What's so crazy about that? Well, so many of the pieces come already fitted with pipes and whatnot so that when the pieces come together on these giant pieces, so much of the crap inside mates up so perfectly.

Plus, on destroyers, there's these huuuuuge jigs that basically flip the pieces upside down and sideways so that welders can do their work in the most efficient manner (e.g., they don't have to weld above their head, just rotate a huge chunk of the ship to be upside down so that you can bend down and weld things together). How the design and construction of such big things can be done so accurately is just mind-boggling to me.
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Old 07-16-2018, 01:19 PM
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As the program grows, you find that certain things become difficult, so you go through a process of refactoring. Refactoring covers a lot of ground but usually it is about generalization--taking a specific implementation and turning it into common functionality. It's like having a hard-wired instrument on your submarine, getting annoyed that the wiring is getting convoluted, and then designing a common power and data plug system that all instruments can use. The wiring is simplified and you gain the flexibility of moving instruments around or designing new ones.
I wonder if Factorio is titled partly as a reference to refactoring (in addition to the concept of factory).

I remember a talk by a KSP developer who talked about wasting a lot of time doing a multitude of ad hoc code before they figured out that they should organize the code into functions and use those as modular blocks that could link to other blocks, much like Voyager's processor modules which are linked up to cache modules.


There is an unobvious trade-off though: If you don't know how big the job will be, how often some elements of it will repeat, what and how much do you organize into those modules? Organizing into modular functions is analogous to automation: It has a large fixed cost but is often only worthwhile if you'll repeat it often, otherwise it may be best done by hand on an ad hoc basis.
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Old 07-16-2018, 01:26 PM
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Submarine toilets are connected to sanitary holding tanks that can be pressurized to overcome the surrounding sea pressure to empty the tanks (while far out to sea). The toilets have a stainless steel ball valve at the drain that can withstand this pressure. The toilets themselves are also made of stainless steel (as are the sinks and showers). Porcelain doesn't work all that well in a vessel that might take battle damage from exploding depth charges.
And the same companies which make porcelain toilets and acrylic toilets make steel toilets. I ought'a know, I had to redesign the whole quality structure for the biggest one in the world

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Similarly, with the possible exception of prisons, nobody would have a need for a bunk with as little space as on a submarine.
That doesn't mean the bunks need to be redesigned for each submarine. If you can use the same model which was used in a different submarine, you save time and the supplier can't whine about needing to get the production line set up.
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Old 07-17-2018, 03:16 AM
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I wonder if Factorio is titled partly as a reference to refactoring (in addition to the concept of factory).
Could be! There is definitely an element of that in the game. A huge amount of time is spent not building things, but building systems that can build things. Eventually, you reach a point where you're stamping down huge self-sufficient factory blocks at a time.

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There is an unobvious trade-off though: If you don't know how big the job will be, how often some elements of it will repeat, what and how much do you organize into those modules? Organizing into modular functions is analogous to automation: It has a large fixed cost but is often only worthwhile if you'll repeat it often, otherwise it may be best done by hand on an ad hoc basis.
All true. This is an advantage a small team (particularly a single person) has--they can choose the path that their ad-hoc reorganization takes. I generally take an attitude of "0, 1, N": that is, something can be done zero times, or once, but beyond that 2 is the same as infinity--that's when you generalize it. Sure, sometimes you might find that you really only do something two or three times, and the generalization was slightly wasteful. But this is rare compared to the opposite case where you end up with spaghetti because you didn't take a hard line somewhere. And sometimes there is value in generalizing something even for small numbers (in particular, avoiding things like copy-and-paste errors).

At a certain level of complexity and team size, you can't really get away with an ad hoc attitude. You have to pick the level of generalization in advance. This has the downside of freezing the design earlier than one would like and requiring more up-front work.
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Old 07-17-2018, 03:21 AM
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another group builds big fuel tanks of various sorts; another builds the metal sheath that it all goes in
Small nitpick--there is rarely a "sheath" separate from the fuel tanks. The fuel tank is the skin of the vehicle. There may or may not be a cylindrical part that joins the rounded ends of the tanks; sometimes they are joined in a way that there is continuous propellant behind most of the length of each stage (called a "common bulkhead").
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Old 07-17-2018, 10:03 AM
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This is a very good question Wesley one that I have often wondered about also. I have served on submarines back at the young age of 19 on diesel submarines and later on to nuclear submarines till I was 28.

My thoughts even as I stood top side watch was how do they build the submarine to be exactly at the level it is while in the water with the sail in the perfect position of port and starboard and not leaning to one side or the other.

In qualifications we learn that the boat has tanks that fill with water to submerge the boat and to surface you blow the water out with high pressure air and then close the tank valve and she surfaces. They call them ballast tanks all carefully designed to balance the whole ship under and above the water. The diesel boat was even harder to understand due to the fuel tanks had to have salt water pumped into them as you use the diesel fuel to balance the sub and keep her on an even keel. They would then separate the diesel fuel from the salt water using fuel water separator's.

This is how BAE in the UK builds their submarines: https://www.designworldonline.com/Su...rtual-Reality/

[QUOTE]
The engineers at BAE use PTC CAD products and turned to Gold PTC Partner Advantage Program member, Virtalis (Manchester, UK) to create, install and integrate Virtual Reality (VR) systems for product development and manufacturing.

Tasked with building three Astute Class nuclear submarines, the engineers decided to accelerate the process using a VR system instead of creating physical prototypes. The VR system had to be easily accessible both to the engineers, as well as to welders and pipe fitters, who would physically build the submarine.

For design, the engineers used the PTC CADDS 5 shipbuilding program, a tool that enables groups of engineers to work simultaneously on design, validation, and machining of the same assemblies. For the VR system, they commissioned Virtalis to integrate the PTC Division MockUp program with Virtalis’ VR tools.

In a large 3D stereoscopic theater, this program exposes potential clashes between submarine components and assemblies. If needed, a redesign can be performed prior to the build.[QUOTE]
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Old 07-17-2018, 10:50 AM
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My thoughts even as I stood top side watch was how do they build the submarine to be exactly at the level it is while in the water with the sail in the perfect position of port and starboard and not leaning to one side or the other.
Designing this into the sub (or any other vehicle) requires accounting for all of the fixed mass. With 3-D solid-modeling programs, this is much easier than it used to be. I'm most familiar with SolidWorks, in which you can design a 3-dimensional part of arbitrarily complex geometry, and as soon as you specify the material type, it will tell you the total mass of the part and the 3-D location of its center of mass. When you put various parts together in an assembly, the program keeps track of where all that mass is, so you'll know in the end whether you've got a nicely balance submarine or whether you need to move some mass around. The software can account for the mass of every nut, bolt, washer, pipe, hose, electrical wire, connector, and other hardware.

This of course does nothing to account for how the movements of the submariners or any stores or munitions within the sub changes the center of mass (google "submarine trim party" for fun). Presumably this is where ballast tanks and/or control trim comes into play. Design software makes it easy to determine how big and where the tanks and/or control surfaces should be to account for various worst-case mass distributions - or conversely, what kinds of mass distributions can be tolerated by a given vessel design.
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Old 07-19-2018, 09:55 PM
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How do they even know if the parts will all work together, or will withstand real world testing?

Sometimes the answer is "they don't."
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Old 07-20-2018, 11:58 AM
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Sometimes the answer is "they don't."
Allegedly, when the Germans took possession of some French submarines after the fall of France in World War II, they were suspicious they'd been duped by the French authorities because some of the bolts in the French submarines tightened clockwise and some counter-clockwise. The orderly German engineers couldn't imagine anyone designing a ship with different directions of rotation for its fasteners.

I don't know the reasoning behind the French design, but my guess would be it made economic sense at the time somehow (or was "not worth the cost of fixing").
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Old 07-20-2018, 06:57 PM
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Allegedly, when the Germans took possession of some French submarines after the fall of France in World War II, they were suspicious they'd been duped by the French authorities because some of the bolts in the French submarines tightened clockwise and some counter-clockwise. The orderly German engineers couldn't imagine anyone designing a ship with different directions of rotation for its fasteners.

I don't know the reasoning behind the French design, but my guess would be it made economic sense at the time somehow (or was "not worth the cost of fixing").
Could it be that vibrations tended to loosen the bolts and those vibrations turned the bolts in opposite directions in different parts of the ship?
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Old 07-21-2018, 05:06 AM
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Could be. Or it could be normally-open and normally-closed bolts. Or that the construction process preferentially allowed tightening in one direction.
.
But The whole thread-cutting business was once much less standardised than it is now, and only gradually changed. Even in the 1930's.
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