Hey, I remember these names from that other thread! Anyway, as someone with personal experience sailing modern dinghies and a layman’s interest in ~18th century sailing vessels, I’m certainly well-qualified to weigh in here!
I think this all looks plausible enough for gaming purposes, especially since you’re going for steampunk approach, but a couple things do jump out to me:
I might swap the decks, maybe? Having the cargo and heavy machinery in the lowest deck makes sense for a sailing vessel, and the nicer quarters and bridge area above, since at sea that’s the deck with the least air and least visibility, plus you get a stability benefit from having more weight at the water-line rather than above it. On an airship thought, most of those dynamics are going to be flipped I think, as the lowest deck is the one that’s hanging down into the air while the upper deck is likelier to be partially built into the hull. Similarly, your lower deck appears to be bigger than your upper one, but given the way the gondola would probably taper as it goes down, this also seems the reverse of what you’d want. The one potential fly in the ointment here is the balloon (maybe better called “hull” or “envelope”?) access, which you’ve currently got on the upper deck. But you could maintain that in the new lower deck if you wanted, if only because you’d need an open space for cargo to be moved through the lower deck on its way to the upper deck, sort of like the deck hatches in a sailing ship that allow cargo to be lifted down into the bottom deck.
(That’s another reason why you might want to flip the decks, by the way. I’d assume you would want a crane of some kind to move cargo down to the ground, but if the cargo areas are in the lower deck, you’d need to fit that crane in ~7 or 8 feet to avoid squishing the upper deck, which doesn’t give you a lot of clearance! But building the cargo areas of the upper deck further into the hull, so they’ve got more vertical clearance, would be a much easier design task).
You’ve mentioned the issue of watches, and yeah, that would be a big one; with only six people, and without much redundancy beyond the two engineers, this would likely be a stressful and risky way to operate the ship for any length of time. I think the scenario you’ve sketched out seems plausible given the constraints they’re operating under, but I think you’d definitely have room to amplify folks’ sleep deprivation and include various errors, breakages, and other unresolved challenges that came up during the voyage, since this is just not adequate to the task. I’m assuming steampunk devices can help with the labor of running the place, but e.g. having the helmsman in a different watch (presumably) than the navigator, for example, is obviously going to create a lot of issues!
Actually, typing that out made me realize one other thing, which is that I’d probably make the captain the navigator and the first mate the pilot/helmsman; the latter is a prestige position on a ship, of course, but a helmsman has to be at the wheel in a moment of crisis, whereas typically the captain might need to go different places and be able to talk and receive information, which is hard to do if they’re consumed with the moment-to-moment requirements of steering.
One other personnel thing – since the structure here is based on an in-setting military, you probably won’t have “two engineers”, you’d probably have a chief engineer and an engineer’s mate.
OK, last thing on this point: if threats are super prevalent in this setting, and you only have one gunner so if you get attacked during one of the four-hour blocks when they’re asleep you need to wake them up and hope they can get the cannons and stuff ready in time, that seems extra super-duper stressful and risky, even under the strained circumstances of the launch here. So I dunno if you’ve decided on the murdered person’s job, but I’d consider making them a gunner’s mate.
Again, this is all top of my head and I’m sure ill-informed, but hopefully of use or at least interest!
First, this sounds like a very cool setup for an IF.
Second, I have to wonder about the “science” areas, since none of the crew seem to be science-oriented. (Perhaps this is due to the skeleton crew issue you mentioned.)
Third, a random thought: This reminds me of Heinlein’s Job: A Comedy of Justice, where one of the alternate realities the main character inhabits never developed airplane travel, and so airships remain the dominant form of aboveground transportation. Might give you some other ideas worth considering.
Surely that means the overall mass of the vessel does not change - it is just redistributed. And will no increase in volume, how can that change the lift?
I’ve written a time travelling saga where a very small part of the game is set aboard the gondola of the D-LZ 129 Hindenburg just prior to the disaster. During my research, I found lots of plans and crew details of the ship. Perhaps something like this would help.
Unfortunately, I didn’t bookmark any web sites at the time, but there is a mass of information available on the Hindenburg, the disaster and airships in general, if you care to look.
According to my notes, there were 97 people on board (36 passengers and 61 crew). Of the crew, nine were in the control room, two were in the navigation room and one was in the observation room. These are the three rooms in the gondola, which is where the fragment of my game takes place. The other crew were scattered in various posts around the ship.
Quite to my surprise, the passenger area was quite large and struck me as being a great location for a game. I didn’t save any of the plans, but remember that it had bedrooms, dining room, smoking room (aboard an airship!) and more.
EDIT: I should have mentioned that my game is not finished, so don’t go looking for it.
Let me first state that you are 100% correct. Just to get that out of the way. I’m absolutely conflating two different lines of thought together, which is what I get when I spout off about something on my phone while trying to juggle other tasks. Belatedly recognizing this, I’ve been (not yet successfully) attempting to edit this post (while taking care to point out edits for those who’ve already read it). Obviously, not quickly enough. (Also, this is one of the reasons why I suggest not using a lifting gas at the end of the post.)
In a classic zeppelin, the rigid shell has a fixed volume, but inside these shells were gas bags that can expand or contract. The buoyancy of the airship could be adjusted by changing the air pressure around the gas bags within the streamlined envelope. A slight increase in air pressure would reduce buoyancy. You’re basically taking on or expelling extra air mass to change the averaged density of the airship, since the volume is fixed. Submarines do the same with ballast tanks that will either fill with heavier seawater or displace that water with air stored in compressed tanks, thus changing the mass of a fixed volume craft, and its overall density.
When I started the post, you can see I make no mention of the airship actually rising until the fifth paragraph. That’s because the liquified lifting gas holding tanks should be on the ground, not the craft. When the airship is finally released, the expelled lifting gas is left with the airfield. Worse yet, I got myself turned around by that point, and forgot this point myself in paragraph eight, and clearly mention releasing liquified gas that wouldn’t be aboard. I was just being straight up dumb at that point.
Anyway, to descend you have two options. One, you can allow normal air into bladder, which adds mass to your ship, increasing overall density and lowering bouyancy. This isn’t great if your remaining lifting gas was something precious like helium, as it mixes with normal air and complicates its recovery. Not to mention, this is only reversable (if you want to increase altitude again) by heating the now mixture of helium and air, thus expelling some of the mixed gases out of one way valves into the atmosphere, forever losing some precious helium.
Or two, you can condense air from the surrounding atmosphere into holding tanks, which adds mass to your ship, increasing overall density and lowering bouyancy. Reversing this would involve blowing your holding tanks, which are effectively ballast tanks here.
What I was trying to originally articulate, but utterly failed in execution, was combining both methods by using something like nitrogen as an unconventional lifting gas.
When initially heating your gas to produce a low volume, high temperature plasma, nitrogen can simply be expelled into the atmosphere without concerns for capture, eliminating the radiator fins and liquified storage tanks altogether. Secondly, nitrogen can be separated from the surrounding air in situ using membrane filtration. This nitrogen can then be fed directly into the main bladder to increase onboard mass. This removes the need for separate ballast tanks, as the main bladder is serving dual roles. And finally, if needed, the bladder can be reheated to expel nitrogen to increase bouyancy again without losing non-renewable helium in the process.
A gondola is something hanging from the hull/envelope. On some airships, typically blimps, gondolas are the only occupied places. Rigid airships (ie, all zeppelins) have most of the occupied areas within the hull. If a gondola is present, it’s primarily for the bridge. The things that house the propellors aren’t IIRC really called gondolas, but instead nacelles; which is the term for any aircraft engine housing outside the body.
Occupied areas of zeppelins tended to be at the bottom of the hull, composing two or three decks at most. But catwalks allowed access throughout the whole hull so that the gasbags could be accessed.
Something you may find useful is that several zeppelins were designed with a door at the tip of the hull for use when moored at special masts. The top of the Empire State Building had such a mast to allow people to get on and off zeppelins in the middle of New York City.
Look up Zeppelin NT for modern rigid and semi-rigid airships.
I’m very interested in the details of these alternatives to hydrogen and helium for lifting gases.
Regarding the mate-as-medic-issue: at sea (at least until a few decades ago) cargo ships with accomodation for no more than 12 passengers were not required to have a doctor as part of the crew. Many shipping companies would nonetheless have a seperate doctor’s cabin and adequate medical equipment aboard, offering free passage to medical professionals. I don’t think a doctor would be needed much aboard an airship, though: either the fresh air at height will do them good or they will regretably have to be jettisoned to prevent it from spreading.
Looking at your map tells me you are intending to power the engines using steam. Just to mention it: steam boilers are pressure vessels, which means steam engines plus their boilers are much (much) heavier than petrol or diesel engines of the same output. Not exactly the most intuitive choice of engine for a lighter-than-air vessel, but i guess it’s called steampunk for a reason. I would think the choice of fuel to be important in terms of dramatic effect. If your boilers are coal-fired, as opposed to oil-fired, you will need a much larger engine room crew.
That makes a lot of sense! I’m going to play around with that and see if any puzzles break if I swap those things around. The “balloon access” room isn’t part of any puzzles at the moment, just scenery, so I can easily swap that to something else.
Oh absolutely. A lot of the reason the puzzles work in the first place is because the ship is struggling to function under these conditions. I’m glad it makes sense to someone who knows these things!
Interesting! I hadn’t thought about that but that also makes sense.
I’d been calling them the “head engineer” and “apprentice engineer” but “mate” is a better and distinctly more nautical term. I’ll swap that in. (During the game, the chief engineer is dealing with a hull breach while the mate is trying to keep the boilers running.)
That also makes a lot of sense, and actually fits perfectly into certain plot and puzzle things. (And conveniently his quarters are right across from the gunner’s.)
Definitely interesting, and distinctly better-informed than I am!
Thanks! I’m a big fan of closed circle mysteries and that’s where this setting really came from: what’s an interesting place I could keep eight people confined for several days?
That’s just bad labelling on my part. That’s the first mate/medic’s area. During the course of the game he’s the person on the crew best equipped to solve the mystery so he’s got the cadaver there (and also various equipment the player will need for their investigation).
Huh, I’ve never read it, but it sounds like good inspiration!
More for injuries (or MURDER MOST FOUL) than disease, is how I’m imagining it, especially with such a small crew.
A very good point! The term “boiler” on the map may end up being metaphorical, in the end—whatever fictional technology is needed to keep the ship aloft requires machinery in those areas, and that machinery needs to be attended periodically and makes the surrounding area unbearably hot if something goes wrong. But it makes sense that actual steam boilers like you’d find on an old ship or locomotive aren’t a great choice for flying.
No, even with the good first aid training required for seamen, a Navigator can’t back up as medical officer, or even corpsman, more so if in your story, the ship is nearing landing (sea parlance, that is, visual/radar contact with terra firma) where the Navigator’s role became fundamental, looking at the shape of the land, and most important, fixing the ship’s position relative land, and plotting and piloting the ship’s safe course at least near the port, where usually the port pilot came aboard for piloting the ship to the mooring (this is also why the guy at the cloche of a Naval bird is called “Aviator”, never “pilot” because, well, aboard a ship a pilot is a very critical position for ship’s safety.
Hence, for a Navigator officier, the safety of the entire ship and crew is much more important on the safety of a single sailor, even the Capitain. and if in your history, the story start few hours prior of the predicted sighting of land (I’ll put aside all things related to dead reckoning…)
oh, discussing a Naval steampunk history under the aegis of a true Naval historian, means involving one whose knew rivet by rivet the quintessence of victorian technology, the pre-dreadnought battleship (in my HDs there’s actually hundreds of Gbytes of .pdf scans of primary sources on these steam-powered steel leviathans, with these two crown jewels:
whose basically, is: everything conceivable about steam(punk) ! there’s no other reference for all thing about Victorian technology. of course duly mirrored here:
tree Engineer |tail -1
76 directories, 324 files
tree Engineering/ |tail -1
55 directories, 237 files
du -sh Engineer*
67G Engineer
54G Engineering
of course, are the ultimate reference for writing a steampunk history, Naval or elsewhere.
What you are describing is, in effect, a hot air balloon. You would need to get it very hot to get the same sort of lift as helium, or use a much bigger gas volume, or more likely a combination of both.
Hmm… Is oxygen removed because it is too reactive at the high temperatures?
Also, the separation of “slow” nitrogen from “fast” oxygen, water and CO2 sounds like nonsense. I mean I found the company that claims to do just that, so I know you are not making up… As far as I can see, the membrane coordinates with the oxygen (forms a loose compound), allowing transpirt through it. The water and (I guess) the CO2 are removed before hand. https://www.pcigases.com/oxygen-solutions/technology/membrane-technology/
First of, are we alright, mate? Maybe it’s just the text failing to transmit mood or context correctly, but you’re coming off just a tad antagonistic, and I’m trying to figure out why.
Like, this is a thread about a steampunk universe including fictional airships potentially fueled by magic, right?
Also, my literal (non-quote) first words in this thread:
Also, when someone flatly admits they’re wrong and tells you that you’re 100% correct, you usually don’t fail to acknowledge that and then move on to an entirely different criticism.
I feel like you’re thinking I’m proposing we build this thing. I’m not. No one should build this thing.
I could just be reading you incorrectly, and if I am, I apologize.
With that said, I’m just going to go on and pretend that we’re having a friendly discussion here and answer your questions in good faith.
So, question one with a proposed hypothetical answer:
Question? Maybe moreso a comment or statement in expectation of a response. Whatever, we’ll call it question 2:
And finally, the last statement, we’ll again call question 3:
Let’s start with question 1.
The short answer is any sane person is going to remove variables. Air composition is not 100% consistent, and spikes in trace gases could cause some unforeseen interactions when adding that sort of energy.
More specifically, the sorts of heat we’re talking about here will dissociate gas molecules allowing them to potentially recombine when cooling.
For example, the extreme heat of a lightning bolt produces nitric oxide (NO), which combines with oxygen to create nitrogen dioxide (NO2). As the whole thing cools, NO2 can then dissolve into reformed water molecules condensing on the inside of the bladder, forming nitric acid.
Another example would be oxygen molecules splitting and then reforming into O3, otherwise known as ozone, which is super unstable and corrosive to most materials.
And even these examples are a gross simplification. Lightning produces hydroxyl (OH) and hydroperoxyl (HO2), two additional oxidizing compounds, and it can also split an oxgen atom off of CO2, forming carbon monoxide (CO). This only takes into account the interactions of the top three constituents of our atmosphere; I wouldn’t want to hazard a guess on the potential interactions of superheated trace gases.
Even if you could figure a way to do this safely, you would be like literal lightning in a bottle, spewing a soup of NOx and Ozone and other reactant molecules in your wake. Just a source of a bunch of potential headaches. I’m sure there are more I haven’t even thought of yet.
Alternatively, if you were using pure helium or pure nitrogen, the atoms were either already separated anyway, as helium is a noble gas, or, in the case of nitrogen, after cooling it would recombine into stable diatomic nitrogen, not having any alternate stable configurations available with other gas molecules.
Moving on to question two.
Not really. The closest analog would be a thermal airship, not a hot air balloon, although both take advantage of the same principles, so I’ll give it to you anyway.
With that said, this is definitely in the realm of semi-plausible fiction, and the ship doesn’t really have a real world analog.
The key differences are the insanely high degree of heating and what the heating is being used for other than generating lift. The energy added into the remaining gas is used to maintain pressure in a mostly evacuated chamber when surrounded by a near 1 atmosphere pressure. It provides structural integrity to a partial-vacuum chamber by increasing the internal pressure to balance out the crushing air pressure pressing in on all sides. This reduces the need to use exotic materials in your partial-vacuum chamber.
That’s why I called it a transistional (perhaps variable would have been a better word choice) vaccuum ship, and not a thermal airship.
Proposed vacuum airships would theoretically have pumps that remove much of the ambient temperature air from a super strong and super light vacuum-chamber, otherwise it would just collapse or it would be too heavy to fly. They don’t have a heating element to combat external air pressure:
Vacuum airships would replace the lifting gas with a near-vacuum environment. Having no mass, the density of this body would be near to 0.00 g/L, which would theoretically be able to provide the full lift potential of displaced air, so every liter of vacuum could lift 1.28 g. Using the molar volume, the mass of 1 liter of helium (at 1 atmospheres of pressure) is found to be 0.178 g. If helium is used instead of vacuum, the lifting power of every liter is reduced by 0.178 g, so the effective lift is reduced by 14%. A 1-liter volume of hydrogen has a mass of 0.090 g.
The main problem with the concept of vacuum airships is that, with a near-vacuum inside the airbag, the exterior atmospheric pressure is not balanced by any internal pressure. This enormous imbalance of forces would cause the airbag to collapse unless it were extremely strong (in an ordinary airship, the force is balanced by the pressure of the lifting gas, making this unnecessary). Thus the difficulty is in constructing an airbag with the additional strength to resist this extreme net force, without weighing the structure down so much that the greater lifting power of the vacuum is negated.
(-From the link above)
So, I’m probably going to regret this, but I’ll going to use the ideal gas law as it’s clean, easy to understand, and shows direct relationships.
p = (nRT)/V
where p, V and T are the pressure, volume and temperature respectively; n is the amount of substance; and R is the ideal gas constant.
In this example, the volume is fixed, and when looking at relationships, we can also disregard the constant, as it’s, well, constant, which gets us:
p = nT
-or, if I may-
Internal Pressure = Internal Mass × Internal Temperature
A stereotypical vacuum airship would just use pumps to reduce the internal mass, thus reducing the internal pressure as a result, creating a growing pressure differential inside and outside the chamber.
This example increases T while decreasing n, so the product of the two remains closer to the same result, reducing the difference in internal and external pressures.
This is also why the heat doesn’t need to be maintained with increased altitude, as internal pressure doesn’t need to be as high to equal a diminishing external air pressure, but you’d certainly need it to get off the ground in the first place.
In addition to what the heat is used for, how exteme of an amount of heat needed is another reason why an analog doesn’t really exist. The reason I was using the chemical products of lightning as an example above is it’s one of the few natural examples of air being turned into plasma. Nitrogen would need to be heated to around 5,000°-10,000° C to become a plasma. The propane burner used in most hot air balloons and thermal airships won’t remotely cut it.
Thus the jokes about Magic or nuclear reactors as your hear source.
And on to question 3.
There are three standard methods used to extract nitrogen from air:
Cryogenic distillation
Pressure swing adsorption
Membrane nitrogen generation
Cryogenic Distillation
Cryogenic distillation involves pulling ambient air into the distillation setup using a compression device. The compressed air is then cooled to about 10°C before being passed through a series of filters to eliminate moisture, oil, water vapor, and other contaminants.
Once the air has been cleaned, it is channeled through a heat exchanger to an expansion engine. The rapid expansion of the compressed gas within the engine will cause its temperature to fall below its condensation point (approximately -195.8°C within 1 atmosphere of pressure) and liquefy. Once liquefaction is achieved, a high purity fraction of nitrogen is distilled out of the air and channeled to storage units.
The other two methods for nitrogen separation exploit the different physical properties of component gases of air to achieve nitrogen extraction. Compared to fractional distillation, mechanical nitrogen separation is a less complicated way to obtain nitrogen gas from air.
Pressure Swing Adsorption
Pressure swing adsorption is based on the preferential adsorption and desorption of oxygen and other gaseous contaminants by a molecular carbon sieve housed within two adsorptive-desorptive towers.
The procedure involves two stages which are coordinated simultaneously.
Adsorption removes oxygen, vapor, and other impurities from a stream of pressurized air allowing nitrogen to flow through to a collecting/ storage unit. This process will continue until the molecular sieve within the adsorptive tower is completely saturated.
Desorption is a reversal of the adsorptive process that released trapped oxygen from the sieve material within a desorption tower. This process will regenerate the molecular sieve in readiness for a new cycle of adsorption.
Membrane Nitrogen Generation
Membrane nitrogen generation uses hollow-fiber membranes to separate the constituent gases in air. The membrane surface is uniquely shaped into hollow fibers that increase the surface area for more rapid permeation.
The process involves pulling atmospheric air into the generator, compressing it, and passing it through a series of filters before gas separation. Once compressed, the air is channeled through a high-efficiency filter to remove water vapor and other particulate impurities.
The cleaner dried air is then exposed to an activated carbon scrubber that removes any remaining particulate or gaseous contaminants. After exposure to the membranes, a nitrogen-rich gas stream is produced.
I went with the latter just because I was trying to reduce complexity. If you’re willing to deal with the engineering, the other two methods could work as well. As for the specific screencap and company, it was 4am, they popped up first. Blame SEO.
Okay, again, another friendly reminder that we’re talking about magic-powered steampunk airships here. With that said, sincerely let me know if you have further questions and I will do my best to answer them, as I hope you can already see here.
I’m glad you’re getting all this info from the smart people, but as it pertains to the size of your gondola, why do you need to be limited by reality? Couldn’t there be an element discovered in your gameworld that is extremely light and makes it possible for a zeppelin to carry a much bigger gondola? I mean, I buy that shit hook, line, and sinker all the time in games and books. Is it more believable that Philip Pullman’s characters traveled in zeppelins with visible souls than that someone discovered some quirky chemistry?
Apologies if I sound antagonistic, it definitely was not meant that way. I was just interested, and you seemed to know what you are talking about. Thanks for the comprehensive answer.
Unfortunately, handwavium bonds strongly to unobtainium. The resulting orichalcum-ore is hard to find, harder to mine, near impossible to smelt into its components. Even then, the trilithium-vapor that is a byproduct of the process would contaminate the entire planet with the handwavium-plant for millenia.
Time to use this Story Research category some more!
As I get ready to start beta-testing (pretty late, I know) there are a few more things I’m looking for inspiration on.
One of the possible endings for the game involves find some evidence of illegal dealings and placing it somewhere that customs can’t miss when they’re inspecting the ship, without the crew catching you in the process. But I’m not actually sure how customs works for transporting cargo. I’m imagining a customs inspector comes aboard, the crew shows them some manifests listing what they’re transporting, and the inspector does a walkthrough of the hold to make sure everything’s (at least approximately) in order; does that sound plausible?
Are there any particular things a customs inspector might need to see that could plausibly be found in a container, where the player character could plant evidence of illegal smuggling?
On a separate note, it sounds like the navigator is going to have a lot of work to do in the last few hours before arrival. I’m imagining checking various instruments, checking maps, reckoning their position, and making sure they’re on course; any other particular things she should be doing, to add some variety to the descriptions? (Since she’s so busy, she’s not really interfering with anything the player does, so she’s mostly background scenery to make the ship feel alive.)
If the evidence is documentary in nature and the destination was a British port working to current British law (I realise that’s a lot of ifs given your genre), it would be as simple as the player character doing something to get paid off at a British port (which could be as simple as having been hired for a single voyage in the first place). By law, this has to be reported if the vessel is commercial. Customs are then required to inspect all the player character’s effects thoroughly. So, hide the document about your person (since a suspicious captain might think to check your luggage before paying you off), go to the official, produce the document (presumably after leaving the crew’s sight).
If it’s an object that would get the player character into trouble if caught (e.g. an actually illegal item), this depends on where and what is being carried. The captain would need to have sent through the manifest and possibly other documentation (again, depending on the items - the tighter the laws on a given item, the more documentation typically must be sent). The minimum requires:
what cargo is on board
how to identify it (visually and potentially by official number)
how much of it there is (by weight and volume, unless it’s something typically only measured another way e.g. large live animals are counted)
where the cargo came from (originally and also the port at which the cargo came on board)
whether customs fees have already been paid on the cargo
whether any of it counts as surplus stores (i.e. cargo that might have originally been brought on board to keep crew, passengers and/or live cargo alive and happy for the voyage but is at a volume that is excessive for needs and reasonable repairs. Non-surplus stores do not need to be formally declared if an onboard record exists of stocks, and good commercial vessels will do that for organisation in any case).
whether any crew has anything in excess of personal travelling stock (this part is like declaring items as a personal traveller, but on a bigger scale.)
All cargo areas, locations where ship supplies are kept and crew storage locations would expect to be inspected, even on a minimal inspection. In theory, all storage areas in any location would be checked on a strict inspection, and I’d expect a strict inspection if the place where the airship docks is any sort of friend to the place where the airship set off, given law enforcement was “about to be involved”.
If going for the “can’t miss” approach (perhaps these are not the best inspectors ever, or perhaps events occurring during the game have soured diplomatic relations), have the player character learn the patterns of how the six crew process their ship. What gets done every time. What gets done most days. What often gets overlooked. The often-overlooked bits (or better still, things the other crew never consider because of how they approach life) are the clues to where to plant the evidence.
Consider whether there are any hidden places in the cargo holds, the lazarette, the mess. Places where ammo, medical supplies or maintenance equipment are kept would also be inspected, so these are also potential places to secret illegal items. Finally, consider the possibility of placing the evidence on the way to one of these locations - particularly if it’s at an angle not seen when leaving the vessel but quite obvious if one has just entered it!
