Airship Altitude

Discussion on playing Earthdawn. Experiences, stories, and questions related to being a player.
Avanti
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Re: Airship Altitude

Post by Avanti » Thu Aug 29, 2019 10:20 am

Ok I made some quick assumptions without explaining. 25% worth of successes to stay aloft - true. But low-grade sailors (non-adepts) would likely have the skill at 2 and around step 5 for willpower which equals to step 7 for the Air Sailing test. Since the step is the average result, you are guaranteed to keep the ship afloat (I know, I'm simplifying here but that is my goal). And staying afloat includes continuing in motion - you can't manoeuvre but also don't suddenly stop (at least nothing in the talent description suggests that). I'm also assuming that making the test every hour just means you do your duties, be that rowing, reefing the sails, splicing the chaffing, cleaning the deck or what have you the captain orders doing.

Again, for simplicity, I would say if you have a relatively green crew you could opt to have 3 shifts 33% of crew each. But if you have a seasoned crew, with average skill of 4-5 and Willpower step of 6-7, plus some sprinkling of adepts, you can go with 25% shifts and still on average generate 50% worth of successes. The bigger the crew, the more those averages work in your favor. No sense in digging into exact chances how often it would fail.
If you were a rough captain (or maybe using slaves?) you could go with what you mentioned about royal navy - multiple short shifts that overtax the crew.
When in danger/combat, you call up the 4th shift (or the off duty shift if using the 33% shifts) to guarantee manoeuvrability.

I heard that ships of old tended to keep to the shore but I imagine Air sailing more akin to sailing the open sea - you would never want to anchor at open sea even if you found shallow enough water. Yes - sailing during the night should be avoided if possible, but when you have a long voyage, would you like to make it to safe port in 7 or 14 days? 14 days of feeding the crew and being open for Sky Raiders to attack? Maybe you can hide a Drakkar sized boat among some trees, but a trading Galley? Will stand out anywhere.

I'm not saying this is the only way to play it, but I want to avoid unnecessary rolls if I can. For me the ship can fly reliably just assuming the correct number of crew is on duty. Even when in combat I would call for a roll only if the captain orders some fancy manoeuvring or the crew took some losses... or when it would up the stakes for the PCs :)

BONUS QUESTION: when rowing in an airship, do you feel the same resistance as if rowing in water?

Slimcreeper
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Re: Airship Altitude

Post by Slimcreeper » Thu Aug 29, 2019 11:31 am

Who said the keel must interact with the earth somehow? I think the oars must also, maybe through the magnetic field (work with me here) and true earth woven into the materials.

ChrisDDickey
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Re: Airship Altitude

Post by ChrisDDickey » Thu Aug 29, 2019 11:54 am

Avanti wrote:
Thu Aug 29, 2019 10:20 am
BONUS QUESTION: when rowing in an airship, do you feel the same resistance as if rowing in water?
3rd Edition Gamemasters companion, page 60. How airsailing works wrote:Air Sailing also provides much of the magic that allows an airship to soar through the sky as easily as an ordinary ship sails across water. A normal wooden oar rowed against nothing but air will do little to move a massive ship, even a free-floating airship. But the symbolic act of rowing combined with the power of the rower’s will has magical effects. Rowing is a symbol of the rower’s desire to move the ship. Air Sailing takes this desire and magically translates it into motive power that drives the airship. This is one of the reasons rowing is commonly used to propel airships: the force of Air Sailing magic usually allows rowed ships to travel more quickly than airships under sail
This seems to me to be saying that you just row the oar against the air with almost no resistance, but the symbolic act of rowing focuses the rowers will, which is what really moves the ship. So it seems to be saying the work is mostly mental.


I did not mean that it says anywhere that the keel must interact with the earth somehow. But I am saying that since the RaW says going with or against the wind only increases or decreases a ships speed by one rating (ie: it is only going a few mph faster or slower), then clearly the ship (in RaW) is not moving with the wind (like a real aircraft does - in the real world, a balloon, zeppelin, or airplane flying in a 20 knot wind, is traveling 20 knots in the direction of the wind, plus any force the craft is generating). It must ether (through magic) have the wind almost not effecting it at all, or the ship is (through magic) moving more in relation to the earth than to the wind. This might (or might not) be due to the keel interacting with he ground far below. But it could just as easily be some other force.

But I will point out that water ships can sail in directions other than directly downwind, by taking advantage of the keel being in water and having certain characteristics of how the keel can move in water, interacting with the sails being in air and the pressure the sails are exerting. If an airship's keel does not interact with anything other than the air (being moved by the wind) that it is in, the same air that the sails are in, then it can't sail in any direction other than directly downwind (through physics of sailing - but possibly can through magic).
Last edited by ChrisDDickey on Fri Aug 30, 2019 2:24 am, edited 1 time in total.

Avanti
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Re: Airship Altitude

Post by Avanti » Thu Aug 29, 2019 3:42 pm

Just found this in the Terror in the Skies:
The galley soars higher and higher, until Yorlk
the steersman tells Drimsby that the Runner has
reached the sailing lane. With the dangerous ascent
over, half the crew stands down. Their work—and
yours—will begin again in eight hours, when you
relieve those who have worked all day on watch or
manning the sails.
Drimsby is willing to let anyone switch shifts as long
as they find someone to trade with them, though he insists
that at least one man with night vision be stationed in the
crow’s nest after nightfall
these indicate that the crew alternates 8h shifts around the clock and during heavy manoeuvring it's "all hands on deck".

Altanius
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Re: Airship Altitude

Post by Altanius » Thu Aug 29, 2019 9:31 pm

ChrisDDickey wrote:
Thu Aug 29, 2019 1:36 am
As gamers, we are all pretty familiar with probability distribution. If there is a 1% chance each hour of something happening, it will happen about every 4 days. If there is a one in a thousand chance of it happening each hour, it will happen every 40 days. An officer who wants to have a long career needs to set the chance of his ship crashing at less than one in ten thousand per hour. Preferably much less.
Honestly, this strikes me as leaning too heavily on mechanics of the RPG. Which are an intentional abstraction intended to mirror life, not represent it accurately. The specter of failure is meant to be pressing, because it makes things dramatic.

I'll explain this with shadowrun rules because it's a bit clearer than the abstract of airships. For those unfamiliar, Shadowrun uses a D6 system where 5-6 is successes and half 1's or more leads to a 'Glitch.' So if we take driving as an example the average human would have a dice pool of 7-8 (4-5 Skill + 3 for attribute)

If they were rolling for driving to work every day, even assuming they only need a single sucess they would
Suceed: ~96% of the time
Fail: ~4% of the time
Glitch (Car accident or similar): ~3% of the time.

Obviously we all don't fail to drive to work once every few weeks and get in accidents once a month. To its credit, SR specifically addressed this by saying that under normal circumstances if you would succeed you do. And (if I were running) I would apply the same logic to airship. If a single shift's average roll is sufficient to pass the test, they do unless something dramatic (attack, storm, etc) is happening. That's where extra sailors come in handy.

ChrisDDickey
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Re: Airship Altitude

Post by ChrisDDickey » Fri Aug 30, 2019 4:29 am

@Avanti Terror in the Skies was not a normal trading mission. It was a desperate race to find an urgently needed McGuffin. As I recall, the Cloud Runner was a small Galley that was carrying no cargo and was carrying extra crew (it's regular crew, plus the PC's, plus every surviving member of the Air Patrol, plus (I think) even more additional crew). Those are very excellent quotes, but they might not be representative of normal everyday operations, but of extra-ordinary operations of an elite and over-sized crew. One that was sailing 24 hours a day due to the emergency.


@Altanius You make extremely excellent points, but when disregarding probabilities of things going wrong, I tend to lean towards what is stated in the book. Yes, one can go into the weeds on the math, but I also think that one ought not simplify things so much that all possibility of failure artificially disappears, and then say that since there is no possibility of failure, then there is no reason why anybody would keep any safety margin. And therefor there is no reason why anybody would do what the book says everybody does. I think that the book had things fairly well balanced. And if one wants to monkey with the balance, one ought to put something on both sides.

Which is to say, that yes, I am leaning a bit hard on the mechanics to say that when the book says it takes X number of crewmen to operate the ship 16 hours a day, it means that the ship can not be safely operated in the long term (more than a day or two) 24 hours a day by those same crewmen. I think that you were leaning equally hard on the mechanics to say why they could.

What seems to be stated in the book is that most airships, under normal operations, seem to keep almost all their crew awake 16 hours a day, and have 8 hours a night anchored with a small anchor watch. Not everybody will be rowing or manning the sails all the time. Some will be cooking, some will be eating, some will be swabbing the deck, but to me the clear implication is that 100% of the crew is pretty busy doing the necessary things to run the ship for 16 hours a day. Thus adding 50% to the daily running time of the ship, ought to require ether a crew that is 50% more skilled (which is possible - but probably more expensive in wages) or 50% larger (which will cut down a little bit in cargo space). Neither of these is impossible to do, but there are trade-offs ether way. And it strikes me that the trade-off of trying to run a ship more 50% more hours with only the standard crew (neither larger nor more skilled than normal) is that you are probably trading off safety. You don't have as many people runing the ship per hour as you would otherwise have.

I figure that using that model of running 16 hours per day, a certain percentage of ships are still lost to hazards or accidents each year. Maybe somewhere between 3% and 10% each year. Which is to say that even with 100% of the recommended crew being on duty during all hours of ship operation, sometimes, ships succumb to hazards. Not often, just a small chance every year. Some of these hazards might be combat hazards (pirates, wildlife, etc), and some might be navigation hazards (storms, mountains, downdrafts, and other things that could be abstracted to the crew not rolling high enough on their air sailing checks). So some of the ships that are lost, are lost due to their crew failing their air sailing checks. Note that one does not always know in advance that one is encountering a hazard. Sailing through a cloud and hitting a mountain is not something that one plans on doing. A routine passage though a mountain pass suddenly becomes dangerous when an unexpected downdraft is encountered. A storm appearing out of nowhere. Which is to say a crew might have already failed a hazard check before they even know they are facing a hazard.

Now obviously I don't recommending that a GM running a large Galley roll a test for 100 crew members every hour and total up the successes. But I do think the GM ought to have a good idea of the probability distribution and the mean time to failure. Assuming a large Galley has a 5% chance to be totally wrecked per year when operating under 100% of recommended crew. One can presume that it has a greater chance of being wrecked if trying to run with 66% of recommended crew every shift. And that it is mathematically fairly likely to crash after only a few days of trying to run with 25% of the recommended crew per shift.

This is not leaning too heavily on the mechanics. This is simply not discounting what the book says is the standard way to run an airship, and then not assuming that the crew will never ever fail to make a roll they would make 99% of the time. I don't think that the ability to make a test much of the time means that they would make the test all of the time. And trying to run a shift with only 25% of the recommended crew is exactly the sort of dramatic event that ought to force a test, just like trying to drive to work with two busted arms would force a test.

Or, n GM is free to ignore that bit of the book where it says most airships only run 16 hours a day. I always felt it was kind of silly anyway. It seems like a ship would ether run only in the daylight hours, or it would run 24/7. 16 hour s day seems pretty weird to me, and any GM is free to ignore it. My preference is usually to just go with what it says in the book, and come up with justifications as to why it might make sense in the game world, but others might want to adjust it to something that makes more sense to them.
Last edited by ChrisDDickey on Fri Aug 30, 2019 5:28 pm, edited 1 time in total.

Altanius
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Re: Airship Altitude

Post by Altanius » Fri Aug 30, 2019 1:51 pm

ChrisDDickey wrote:
Fri Aug 30, 2019 4:29 am
@Altanius You make extremely excellent points, but when disregarding probabilities of things going wrong, I tend to lean towards what is stated in the book. Yes, one can go into the weeds on the math, but I also think that one ought not simplify things so much that all possibility of failure artificially disappears, and then say that since there is no possibility of failure, then there is no reason why anybody would keep any safety margin. And therefor there is no reason why anybody would do what the book says everybody does. I think that the book had things fairly well balanced. And if one wants to monkey with the balance, one ought to put something on both sides.

Which is to say, that yes, I am leaning a bit hard on the mechanics to say that when the book says it takes X number of crewmen to operate the ship 16 hours a day, it means that the ship can not be safely operated in the long term (more than a day or two) 24 hours a day by those same crewmen. I think that you were leaning equally hard on the mechanics to say why they could.

This is not leaning too heavily on the mechanics. This is simply not discounting what the book says if the standard way to run an airship, and then not assuming that the crew will never ever fail to make a roll they would make 99% of the time. I don't think that the ability to make a test much of the time means that they would make the test all of the time. And trying to run a shift with only 25% of the recommended crew is exactly the sort of dramatic event that ought to force a test, just like trying to drive to work with two busted arms would force a test.
Honestly, we may simply need to agree to disagree because out starting assumptions about how this works might be a bit too different to resolve. However, to clarify, I am not saying failure (particularly catastrophic failure of the 'Skyship is plummeting out of the sky variety) is impossible and thus should be ignored. I'm saying it's much (much, much) more unlikely than any RPG represents. If we equate the skyship plummeting from the sky to a car accident (which I would consider to be a pretty poor metaphor) just think about how often you get in accidents. In my driving for the past decade, I've been in exactly 1 accident while I was behind the wheel. And that's with one person driving, not a whole crew who can catch each others mistakes and cover for each others failings (Which is why I consider it a poor metaphor.)

So (IMO obviously) the possibility of an airship falling out of the sky is like the result of either a grossly incompetent crew or a domino effect of frag ups. To assume such catastrophic failure is likely or happens regularly simply because the dice statistically allow for it is (again IMO) definitionally leaning too heavily on the mechanics.


I figure that using that model of running 16 hours per day, a certain percentage of ships are still lost to hazards or accidents each year. Maybe somewhere between 3% and 10% each year. Which is to say that even with 100% of the recommended crew being on duty during all hours of ship operation, sometimes, ships succumb to hazards. Not often, just a small chance every year. Some of these hazards might be combat hazards (pirates, wildlife, etc), and some might be navigation hazards (storms, mountains, downdrafts, and other things that could be abstracted to the crew not rolling high enough on their air sailing checks). So some of the ships that are lost, are lost due to their crew failing their air sailing checks. Note that one does not always know in advance that one is encountering a hazard. Sailing through a cloud and hitting a mountain is not something that one plans on doing. A routine passage though a mountain pass suddenly becomes dangerous when an unexpected downdraft is encountered. A storm appearing out of nowhere. Which is to say a crew might have already failed a hazard check before they even know they are facing a hazard.
I'm not denying that some percentage of airships are lost due to hazards, attacks and a few to simple human stupidity (Though 10% seems quite high), but any navy that allows more than a handful of ships to be lost to failed airship tests or flying into mountains wrapped in clouds has serious problems because both of these are preventable. This is why militaries establish doctrine and protocol, to prevent things like this. Storms, downdrafts and the like are down to the skill and training of the crew, but assuming any large number of airships are lost due to failed airship checks or flying into a mountain is to assign considerable foolishness to the namegivers of Earthdawn.

ChrisDDickey
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Re: Airship Altitude

Post by ChrisDDickey » Fri Aug 30, 2019 7:53 pm

In our world ships and airplanes hit things all the time. Recreational boaters and flyers yes, but also professional or military crews. Oil tankers and cruise ships on rocks. Military ships on sand bars. Ships crashing into each other. Airplanes crash into mountains. It happens all the time.

I see one reference which says that in 2013 94 ships of more than 100 tonnes were totally lost at sea.
I did not count them, but https://en.wikipedia.org/wiki/List_of_s ... ks_in_2017 lists probably around 200(?) shipwrecks. Not all of these ships on this list were total losses, one that caught my eye was when Arleigh Burke-class destroyer USS John S McCain collided with a Liberian ship with 10 sailors killed. So this list includes incidents where the ships were damaged and crew killed, but not necessarily totally lost. But many on the list were total losses.
On 23 August 2017 3 cargo ships, two tankers and a bulk carrier were lost to Typhoon Hato. 3 were driven ashore, 1 broke in two, one floundered, and one was abandoned. This was only the third most listed Typhoone/Hurricain that year, Typhoon Damrey took 11 ships.


It is sometimes an accidental mistake on somebodies part. Maybe just not paying sufficient attention.
Sometimes it is more of a poor decision, knowing that there is a risk, but assuming it you will be lucky or skillful enough to succeed on a risky maneuver.
Sometimes it is just bad luck, and the typhoon jigs when everybody thought it would jag.

With today's technology it happens a lot less often than it used to. Google Maps in a car is a very nice luxury and handy feature. But in the last several dozen years electronic chart plotters fed by GPS have saved countless lives and damage in boats and aircraft. Satellite weather maps and short-wave radio has saved countless more. Even with all the electronic systems modern ships and aircraft have available, professional crews still occasionally manage to run their craft into the ground. It used to happen a whole, whole lot more 30 or 50 years ago when the navigational aids were more crude, and was actually common back when there were no electronic navigational aids, or even no aids of any kind.

So 100 or 200 merchant and military vessels out of 50,000 is not a bad ratio, but it can't really be considered negligible or that it does not happen.

I tried to find some estimates for ancient shipping (say roman times), but all I found was Norwegian statistics from 1866-1870 show a wreck rate of less than 0.5% per voyage (not year, voyage) most ships would make more than one voyage per year. If you assume the average is 2 voyages a year, then the wreck rate was 1 percent per year, and I would expect the 19th century Norwegians to have much lower wreck rate than any BC civilization which I think would be a better comparison for Barsaive Air Sailing. And I would consider air sailing to be a more dangerous activity that water sailing.
From "The Merchant of Venice", it sounds as if Antonio would not have been surprised at all to loose one or two of his five ships. It was reports that he had lost all five that dismayed him.

Yes, 10% losses is a very high estimate. I included it only because of Terror In the Skies, in which it is stated that 3 or 4 ships were lost near Travar in just 3 weeks. This was probably the loss of 10% or more of the Cargo Airships in all of Barsaive in just those three weeks. I would think that more common losses would be 3 to 5 percent per year. Not 10% per three weeks.


And once again, my point is absolutely not that ships plummet out of the sky with undue frequency (I don't consider 3 to 5 percent wreck rate per year to be undue for ancient craft). My point has always been that in RaW, the listed crew size for a ship is the number of crew that is required to run the ship safely for 16 hours a day. That is what it says in the book. Once again, a GM can decide that that does not suit him and choose to ignore it. Or decide that it is really the number of crew required to run the ship 24/7. But that would be a difference from what it says in the book. (the 3rd edition book, I understand the 4th edition air sailing rules are coming). And if it not the GM who decides to make a house rule, but a player who feels that he does not need quite so great a margin in his Air Sailing tests, then constantly running short handed could affect your wreck rate.
Last edited by ChrisDDickey on Sat Aug 31, 2019 3:20 am, edited 1 time in total.

Altanius
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Re: Airship Altitude

Post by Altanius » Fri Aug 30, 2019 9:03 pm

ChrisDDickey wrote:
Fri Aug 30, 2019 7:53 pm
In our world ships and airplanes hit things all the time. Recreational boaters and flyers yes, but also professional or military crews. Oil tankers and cruise ships on rocks. Military ships on sand bars. Ships crashing into each other. Airplanes crash into mountains. It happens all the time.
<snip>
Yes, 10% losses is a very high estimate. I included it only because of Terror In the Skies, in which it is stated that 3 or 4 ships were lost near Travar in just 3 weeks. This was probably the loss of 10% or more of the Cargo Airships in all of Barsaive in just those three weeks. I would think that more common losses would be 3 to 5 percent per year. Not 10% per three weeks.
This all is interesting, but I'm not sure it's really a valid comparison. There are 7 billion people on earth, many of them with questionable qualifications. How many boats are there in the world? I have no idea. (I found a metric that there's ~50,000 merchant vessel in the world, but this list of shipwrecks includes ferries which I don't think count as merchant vessels.) and the page you linked doesn't provide any qualifications for it's shipwrecks, either. I found a few in there that mention they were sunk because they were used as target practice, etc.
ChrisDDickey wrote:
Fri Aug 30, 2019 7:53 pm
And once again, my point is absolutely not that ships plummet out of the sky with undue frequency (I don't consider 3 to 5 percent wreck rate per year to be undue for ancient craft). My point has always been that in RaW, the listed crew size for a ship is the number of crew that is required to run the ship safely for 16 hours a day. That is what it says in the book. Once again, a GM can decide that that does not suit him and choose to ignore it. Or decide that it is really the number of crew required to run the ship 24/7. But that would be a difference from what it says in the book. (the 3rd edition book, I understand the 4th edition air sailing rules are coming). And if it not the GM who decides to make a house rule, but a player who feels that he does not need quite so great a margin in his Air Sailing tests, then constantly running short handed could affect your wreck rate.
As I said, I think our starting assumptions on how this all works are too different. You're absolutely correct by the canon of 3rd edition that it list 16 hours, but that still strikes me as nonsensical. If the only limitation really is the number of crew, why not just add more crew so you can run 24 hours?

/shrug.

To each their own.

ChrisDDickey
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Re: Airship Altitude

Post by ChrisDDickey » Sat Aug 31, 2019 4:10 am

Altanius wrote:
Fri Aug 30, 2019 9:03 pm
but that still strikes me as nonsensical. If the only limitation really is the number of crew, why not just add more crew so you can run 24 hours?
I totally agree.

I think the other very significant limitation is the number of daylight hours. Flying at night will not feel (nor be) as safe as flying in the daytime. Therefore, in my mind the division that makes sense is that some ships will only fly daylight hours, and other ships (with much larger crews) fly 24/7.

The whole business with "well we mostly do not fly at night, but we do fly a few hours every night and thus take off and/or land at night" strikes me as utter nonsense and the worst of all possible options that includes all the disadvantages of all the other options. If you are prepared to fly a few hours every night, and ether take off or land at night (the most dangerous and difficult maneuvers), then you probably ought to just hire enough extra crew so that you can fly all night and avoid both the take-off and landing.

But if we do eliminate the 16 hours a day option, I do feel that there would be a significant number of ships that would choose to fly only daylight hours.

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