Underwater Rope Trick

[Zaruthustran]

What happens when you cast Rope Trick underwater?

1. Does the extradimensional space immediately flood?
2. Does it flood only while someone enters or exits?
3. Does it never flood?

The spell description says:
"Spells cannot be cast across the interdimensional interface, nor can area effects cross it."

However, it does not mention air supply directly, only that the space is a place of safety (and thus, normally has air). But what if the spell is cast by an aquatic creature?

Does this mean that the extradimensional space is filled with whatever is around it at the time of casting: it fills with air when cast on land, water when cast underwater?

After thinking about this for some time, I've come up with a fourth option:

4) Just follow Monte's advice and forget about trying to deduce magic with science. Rope Trick simply creates a safe space. If you're an underwater air breather and want a safe space filled with air, the Rope Trick creates a space filled with air and never floods.

But I'd love to hear your opinion.

 

[pontus]

Or maybe:

5. The spell fails to manifest underwater.

 

[Galfridus]

Unless there was something in the spell text which implied that air was necessary, I would rule that the space immediately floods, as physical objects cross freely into the space.

 

[Artoomis]

It depends.

If you think it makes a space that has "walls" like a roon, then water cannot enter, except in dribs and drabs Why? The same reason you can hod a glass upside-down underwater and not have it fill with water.

I'll forgoe explaining the physics involved.

If it floods, the air the water it displaces must go somewhere - other than out the bottom, that is.

So does it flood? I guess that depends on whether you think the air supply is infinite. If the air supply is infinite and flowing freely between the interdimensional space and the dimension from which it comes, then I suppsoe you could flood the a good part of the dimension that holds all the air.

That's all a bit silly, I say it works and that's it. It's a clever survival trick if you get stuck underwater and can't breathe - I'd allow it.

 

[Zaruthustran]

You know, I completely forgot about the upside-down glass thing. That's a really clever point.

 

[Staldin*Freefall]

I like the Monte answer best. Any suggestion that a spell just doesn't work underwater just seems like a cop-out to me. I'm also a proponent of the bell-jar theory.

 

[Zerovoid]

It depends.

If you think it makes a space that has "walls" like a roon, then water cannot enter, except in dribs and drabs Why? The same reason you can hod a glass upside-down underwater and not have it fill with water.

I'll forgoe explaining the physics involved.

If it floods, the air the water it displaces must go somewhere - other than out the bottom, that is.

So does it flood? I guess that depends on whether you think the air supply is infinite. If the air supply is infinite and flowing freely between the interdimensional space and the dimension from which it comes, then I suppsoe you could flood the a good part of the dimension that holds all the air.

That's all a bit silly, I say it works and that's it. It's a clever survival trick if you get stuck underwater and can't breathe - I'd allow it.

To get even more technical... depending how far you are underwater, and the pressure of the air in the rope trick, the air will be compressed, and it will flood partially.

 

[Oogar]

You will still run out of air, unless you create a mechanic for fresh air naturally being created as time goes by. Hmmmm