What do you think...

[tinman]

...the overall effect of a loaded supertanker falling from 2km onto a large city would be?

 

I'm having a hard time wrapping my head around this one.

 

Clearly the impact alone would be tremendous, but what about the oil? There would certainly be enough heat generated to ignite the oil, but would it be dissipated enough by the impact to actually explode or would it simply spread and burn?

 

Secondary fire sources (burst gas mains, flammable buildings, asphalt, etc.) would likely spread the fire well beyond the initial zone of effect, but would a firestorm be likely to develop?

 

What about the downwind effects from that much smoke and particulate?

 

What would be the best way to model this kind of event in HERO terms?

[Cancer]

Re: What do you think...

 

It's not supersonic at impact; the velocity is only about 200 m/s.

 

Drawing numbers from here, posit 200,000 tons of oil on a ship with an empty mass of 200,000 tons. The ship is 350m long by 55 m wide by 35 m deep. That's the "footprint" of the falling object. Very crudely, that makes for 20 tons per square meter fallling, with that 200 m/s velocity, in the impact footprint. You can probably turn that into Hero-style KA damage.

 

You'll also have tsunami-like damage done by all that liquid (with its density of about 0.9 tons per cubic meter) being bounced away from the impact as the tanker structure is crushed.

 

The impression I have (from reading discussions of the firestorms resulting from WW2 strategic bombing) is that firestorms don't really come from a single big fire. To get one going, you need lots of lesser fires over a large fuel-rich area. I don't think this will make a firestorm. It'll be a very large nasty fire, but not a firestorm.

 

If you were to spread the oil out in a layer 1 m deep, then that makes a circle about 250 m in radius. If you make that 10 cm deep, then it's about an 800 m radius. So that's probably about the size of the area directly covered with the burning oil.

 

The big tankers carry crude, which isn't going to explode, and isn't as flammable as its refined products (gasoline). It also doesn't burn as cleanly, so you'll have yucky black smoke from the oil fire. I would look to descriptions of being downwind of the oilfield fires in Kuwait after the Iraqi invasion in 1990 (or '91, I forget) for that. The wind matters, both for smoke, and for the progress of the "collateral damage" fires that break out after impact.

 

Offhand, I'd say total destruction for a 1-kilometer radius around the center of the impact, and severe damage for another kilometer.

[Guest Black Lotus]

Re: What do you think...

 

It'd crush whatever structures/ vehicles/ creatures it fell on, create a respectable indentation in the concrete, cause a small localized earthqquake, send debris shooting around when it lands, and cause a mighty large dust cloud. I'm guessing it'd also be crushed and break up, sending pieces of itself spinning about.

 

It's be moving at 250 ft/s or so after a 2 km fall, somewhere terminal velocity for sure.

[NuSoardGraphite]

Re: What do you think...

 

Oooh, Good scenario!

 

I'd treat it as a really big explosion, then beyond the effects of the explosion, a continuous RKA thats spreading.

 

I would use the secondary fire effects (gas mains exploding etc) as distractions to add tension to an already tense situation....they happen at dramatically important moments of course (the fire seems to be under control, then BOOM)

 

What dastardly villian is planning an attack of this magnitude on our heroes city???

 

Thats pretty ruthless!

[NuSoardGraphite]

Re: What do you think...

 

am I mistaken in thinking that 400 thousand tons at 200 meters per second can generate somewhere on the order of 16 Trillion Joules of impact energy?

 

If so, thats about a 35 DC attack (using an exponential scale of X2, starting with 100 Joules = 1 DC) or 11 1/2D6K. Large enough to be considered on an Atomic scale. (a 1 Kiloton nuke comes out to about 13D6K or thereabouts)

 

The base damage should be localized in the Area of Effect the size of the Tanker itself. Beyond those hexes, it should be treated as an Explosion (maybe -1DC per 2 hexes instead of -1/1")

[tinman]

Re: What do you think...

 

What dastardly villian is planning an attack of this magnitude on our heroes city???

 

Thats pretty ruthless!

 

Actually, it already occurred, but I had to wing it and I'm not sure I got the scale or effects of the devastation right.

 

Essentially the scenario was that a group of metahuman supremacists were staging a protest which included holding the tanker above Manhattan as a means of instilling fear and awe in the "lesser beings". They never intended to actually drop it, merely use it to make a point.

 

When the PC's rushed to intervene a struggle ensued and the telekinetic who was actually holding the tanker got taken out. The PC's had figured that between them they could easily carry it to safety, but they were about two orders of magnitude off in their calculations.

 

It honestly never occurred to me that the PC's would take that route, I figured they would defuse such a hair-trigger situation through diplomacy. As a result I hadn't really put much thought into the outcome if the tanker actually fell.

[Cancer]

Re: What do you think...

 

If you're going to do this, you might do some thinking about what superhero PCs might be able to do about it before impact.

 

If you just materialize the tanker 2 km up, then the answer is "not much". There'll be 20 seconds of free-fall time before impact.

 

Trying to lift the thing back up, or deflect it, isn't going to work, if you do the Superman-style fly up to it and catch it in your hands. The tanker doesn't have the strength to support its own weight. The STR you compute for moving that 400,000 tons has to be applied approximately uniformly over the whole tanker surface, or you'll just break the tanker apart; the pieces other than the one in Superman's hands will keep falling, and now they fall slightly away from each other, widening the zone of destruction. If that happens high enough up, then the oil will disperse over a much larger area. If you have a way of igniting it after that (it won't ignite on impact by itself), that could give your the widely dispersed fires you need to start a firestorm.

[Hawksmoor]

Re: What do you think...

 

Shows you what most heroes think about situations they get in.

 

Punch first, rescue bystanders second.

 

This I believe comes from the fact that HERO evolved very strongly from table top wargaming (disagree? look at the movement and combat systems...HERO can be played as a WH2K game) and thus there are few systems for interaction resolution and XPs are not expressly awarded to motivate more peaceful methods.

 

I would have the characters really, really examine the impact of their actions as they certainly doubled or tripled the impact of a 9/11 type event on a major city.

 

Hawksmoor

[Cancer]

Re: What do you think...

 

Woof, you've done it already. Ooooh. Man, the authorities are gonna be after the PCs now. The cure was much worse than the disease.

 

I like it. "Neutral evil gamemasters have the most fun."

[tinman]

Re: What do you think...

 

am I mistaken in thinking that 400 thousand tons at 200 meters per second can generate somewhere on the order of 16 Trillion Joules of impact energy?

 

If so, thats about a 35 DC attack (using an exponential scale of X2, starting with 100 Joules = 1 DC) or 11 1/2D6K. Large enough to be considered on an Atomic scale. (a 1 Kiloton nuke comes out to about 13D6K or thereabouts)

 

The base damage should be localized in the Area of Effect the size of the Tanker itself. Beyond those hexes, it should be treated as an Explosion (maybe -1DC per 2 hexes instead of -1/1")

 

Unless I'm off by a decimal place, that seems about equal to a magnitude 5 earthquake...

[Hawksmoor]

Re: What do you think...

 

If you're going to do this, you might do some thinking about what superhero PCs might be able to do about it before impact.

 

If you just materialize the tanker 2 km up, then the answer is "not much". There'll be 20 seconds of free-fall time before impact.

 

Trying to lift the thing back up, or deflect it, isn't going to work, if you do the Superman-style fly up to it and catch it in your hands. The tanker doesn't have the strength to support its own weight. The STR you compute for moving that 400,000 tons has to be applied approximately uniformly over the whole tanker surface, or you'll just break the tanker apart; the pieces other than the one in Superman's hands will keep falling, and now they fall slightly away from each other, widening the zone of destruction. If that happens high enough up, then the oil will disperse over a much larger area. If you have a way of igniting it after that (it won't ignite on impact by itself), that could give your the widely dispersed fires you need to start a firestorm.

 

Ah...real world physics.

 

But these are the comics of super action heroes (and the RPG that portrays them) thus the tanker slows down, its fall is arrested and moving slowly under the vast bulk the hero flies the laden tanker to the harbor setting it down past the Coast Guard cordon where clean up crews are already being dispatched.

 

That is comic book physics.

 

Of course Comic Book Physics also have the tanker detonating and taking out half of downtown and covering the rest in burning crude sludge.

 

Hawksmoor

[tinman]

Re: What do you think...

 

Shows you what most heroes think about situations they get in.

 

Punch first, rescue bystanders second.

 

This I believe comes from the fact that HERO evolved very strongly from table top wargaming (disagree? look at the movement and combat systems...HERO can be played as a WH2K game) and thus there are few systems for interaction resolution and XPs are not expressly awarded to motivate more peaceful methods.

 

I would have the characters really, really examine the impact of their actions as they certainly doubled or tripled the impact of a 9/11 type event on a major city.

 

Hawksmoor

 

Considering the political fallout from 9/11 it would probably be safe to say that this event will be at the heart of government policy concerning metahumans for at least the next few decades, and not just in the US.

[Hawksmoor]

Re: What do you think...

 

And suddenly the PCs are either told to retire (a la the Incredibles) or are forced to by an adminstration that has to been seen as cracking down on dangerous Metahumans.

 

Hawksmoor

[tinman]

Re: What do you think...

 

Between them the PC's had the combined might of 60 STR, 40 STR, 70 STR and 35 STR TK. The PC with 60 STR was able to use it to affect an entire object (indirect).

 

The NPC holding the tanker had 120 STR TK and was visibly straining. In the past she had hit them with up to 20d6 worth of Turtle-style smack-down.

 

I can't believe they thought they could hold it up.

[Cancer]

Re: What do you think...

 

Considering the political fallout from 9/11 it would probably be safe to say that this event will be at the heart of government policy concerning metahumans for at least the next few decades' date=' and not just in the US.[/quote']

 

Absolutely! I imagine most places will just go for the "Final Solution" to the "metahuman question" after that incident. And the PCs did it purely to themselves! Absolutely glorious! GM Brilliance of the first magnitude. Time to lean on the rep button.

[tinman]

Re: What do you think...

 

And suddenly the PCs are either told to retire (a la the Incredibles) or are forced to by an adminstration that has to been seen as cracking down on dangerous Metahumans.

 

Hawksmoor

 

Forced retirement seems a little light...

[tinman]

Re: What do you think...

 

Absolutely! I imagine most places will just go for the "Final Solution" to the "metahuman question" after that incident. And the PCs did it purely to themselves! Absolutely glorious! GM Brilliance of the first magnitude. Time to lean on the rep button.

 

Although I love to bask in praise, it is entirely undeserved. I was taken totally off guard by how it went. I actually had to just end the session so that I could take some time to consider the consequences (immediate and otherwise).

 

It's all grist for the mill though...

[Hawksmoor]

Re: What do you think...

 

Forced retirement seems a little light...

 

I meant *all* superheroes.

 

Everywhere.

 

-The team in question are another matter entirely. Serious psychological issues for them I suspect. Only the casual killer can get off scott free emotionally. Then there is the world wide suspicion that they caused the accident. The authorities are going to get involved and the result could be serious jail time and if the character's are backed by a philanthropic organization civil lawsuits.

 

Hawksmoor

[Cancer]

Re: What do you think...

 

Although I love to bask in praise, it is entirely undeserved. I was taken totally off guard by how it went. I actually had to just end the session so that I could take some time to consider the consequences (immediate and otherwise).

 

It's all grist for the mill though...

 

I am a firm believer in the principle that "Luck is the residue of design."

 

Creating a situation where that kind of (unintended, even unimagined) result is possible is a sign of greatness. You have made a world where no one knows all the consequences of their actions, even though they may be truly horrific: the ultimate in role-playing realism.

[sbarron]

Re: What do you think...

 

Between them the PC's had the combined might of 60 STR, 40 STR, 70 STR and 35 STR TK. The PC with 60 STR was able to use it to affect an entire object (indirect).

 

The NPC holding the tanker had 120 STR TK and was visibly straining. In the past she had hit them with up to 20d6 worth of Turtle-style smack-down.

 

I can't believe they thought they could hold it up.

Yeah, they weren't even close.

[tinman]

Re: What do you think...

 

I am a firm believer in the principle that "Luck is the residue of design."

 

Creating a situation where that kind of (unintended, even unimagined) result is possible is a sign of greatness. You have made a world where no one knows all the consequences of their actions, even though they may be truly horrific: the ultimate in role-playing realism.

 

shucks...

[Hawksmoor]

Re: What do you think...

 

Between them the PC's had the combined might of 60 STR, 40 STR, 70 STR and 35 STR TK. The PC with 60 STR was able to use it to affect an entire object (indirect).

 

The NPC holding the tanker had 120 STR TK and was visibly straining. In the past she had hit them with up to 20d6 worth of Turtle-style smack-down.

 

I can't believe they thought they could hold it up.

 

Actually they might be close depending on the flight powers of the team. You can add inches of flight to str under the right circumstances.

 

Now the event has already happened but a 2km fall as Cancer said would take about 20 seconds at least. That is bizarely plenty of time to come up with a solution. If the team could stop it they might have been able to divert it to a lower population area or at least slow the plummet so the impact was less. Of couse the tanker would rupture the three layer membrane and double hull upon any impact but true heroes could have found some way around it.

 

Now to lay out a small thought:

 

Rewind time.

 

Let the PCs do it all over again. Say a precog from the city sees herself die in the incident. She then goes to the Heroes and says "I saw myself die today. You can't do what you are planning on doing. If you do lots of people will die."

 

You don't actually have to break the game on the boneheaded decisions of the players.

 

Hawksmoor

[Hugh Neilson]

Re: What do you think...

 

Actually they might be close depending on the flight powers of the team. You can add inches of flight to str under the right circumstances.

 

Now the event has already happened but a 2km fall as Cancer said would take about 20 seconds at least. That is bizarely plenty of time to come up with a solution. If the team could stop it they might have been able to divert it to a lower population area or at least slow the plummet so the impact was less. Of couse the tanker would rupture the three layer membrane and double hull upon any impact but true heroes could have found some way around it.

 

Now to lay out a small thought:

 

Rewind time.

 

Let the PCs do it all over again. Say a precog from the city sees herself die in the incident. She then goes to the Heroes and says "I saw myself die today. You can't do what you are planning on doing. If you do lots of people will die."

 

You don't actually have to break the game on the boneheaded decisions of the players.

 

I second the "rewind" theory. Depending on the nature and backgrounds of the characters, it may be possible to build something like this from their own SFX and backstories. Timetravelling or precognitive NPC's who are already established would be the appropriate next choice. If all else fails, there's the classic Star Trek coincidence that when we make our worst decisions just happens to be when there's a tear in the fabric of space/time.

 

Maybe the do-over comes at a price. The characters could have to sacrifice something to get an opportunity to fix their mistake. You could even set up a scenario where it looks like they can reverse the disaster at the cost of their own lives, and create something in-scene which allows them to survive (or not - "you made the mistake, and now you'll have to clean it up" at least allows the characters to go out heroically).

 

Now, one really mean option would be "As you sink into the pit of despair watching the tanker approach the ground, your minds conjure up images of the devestation which will result to the city due to your overestimation of your own abilities. Suddenly..."

 

deus ex machina. Lots of scenarios are possible.

 

(a) The tanker vanishes without exlanation

( A bolt of (insert SFX here) strikes the tanker from [above/below], vaporizing it

© The tanker stops in mid-fall, slowly moves outside the city (or to the harbour), and settles gently to earth.

 

The heroes can't find out how it was stopped. You can come up with the desired scenario later, but they have to live with knowing someone else pulled their fat out of the fire. Sooner or later, someone will come to collect on that debt.

 

Maybe the press even credits the heroes, making it that much worse when the true rescuer is revealed.

 

Or you could be really kind and say "Clearly you guys didn't think it al through. We can rewind to the start of the situation and you can try again", likely with xp penalties all round.

 

Or you leave matters where they lie and let the PC's deal with the political fallout. Hope their secret ID's are well protected, since that's their best hiding place.

[BlackSword]

Re: What do you think...

 

Yeah, at the very least the next session can start with...so there is the tanker, just beginnig its fall, youhave 20 seconds to do something. Being time sensitive say 1 minute = 1 second, so they would have 20 minutes to work on a solution. Hugh has some good ideas as well.

 

If the tanker hits the ground its pretty much the end of the campaign as is. The destruction will be brutal, metahumans will be blamed. Nastiness will ensue.

[Cancer]

Re: What do you think...

 

Another idea into the bucket ... in the replay, give one or more of the PCs the ability to "play the Martyr card", to borrow a situation from TORG: save the day at the price of his own life. Like, perhaps, let that PC with the indirect strength buy more STR at the cost of BODY damage ... at a rate guaranteed to irretrieveably destroy the character, 1 STR per 1 BODY or something. Then the character chucks the tanker out into the North Atlantic, his head explodes, and suddenly that PC is a sainted martyr instead of a mass murderer. From such stuff are great comics made.