So this just happened:

[ZamielVanWeber]

We have to get the party through a lava infested dungeon. We have a small number of lava stones, two people who can fly, and some Marvelous Pigments. So I declare that we need a canoe made out of a substance that it a poor conductor of heat with a high melting points. My DM declares that I would need a Knowledge (Thermodynamics) check. The person with Elf Dilettante promptly does so and rolls a natural 18, success. I start looking up materials that could qualify. End result is that our party had a canoe made out of salt. We are moving around the Fire Temple of Eurynome in a salt canoe.

I hope we never forget this.

[Belzyk]

We have to get the party through a lava infested dungeon. We have a small number of lava stones, two people who can fly, and some Marvelous Pigments. So I declare that we need a canoe made out of a substance that it a poor conductor of heat with a high melting points. My DM declares that I would need a Knowledge (Thermodynamics) check. The person with Elf Dilettante promptly does so and rolls a natural 18, success. I start looking up materials that could qualify. End result is that our party had a canoe made out of salt. We are moving around the Fire Temple of Eurynome in a salt canoe.

I hope we never forget this.

Slap on some fire immunity. Fire immunity allows for swimming through Lava. But I'm reality lava is way to dense to sink into so you'd be able to walk across it or Wade through it like shallow water without sinking to much.

[ZamielVanWeber]

The two flyers have fire resistance and no way to share it with the non-flyers.

[Gildedragon]

Pretty sweet.
I'd say the DM ought have called for Kn: Engineering as Kn: Thermodynamics didn't exist before and thus the check couldn't have been done without something as fortuitous as the dilettante.

[Elxir_Breauer]

Knowledge (Engineering) or (Arcana), maybe (Planes); I would have accepted whichever was available of those, with Engineering having the lowest DC, then Arcana at+2-5 DC, and Planes a bit above that. Not a terrible call as given though, with the Dilettante around. I tend to give certain real-world Knowledge types a bit of leeway in 3.5/PF though because in many cases they are indeed covered by more than one area of expertise.

[Yahzi]

We are moving around the Fire Temple of Eurynome in a salt canoe.
Well, that's nice. Add some pepper and a little garlic and I am sure the critters that live there will appreciate the finely seasoned barbeque. Because just not touching lava is as helpful as not touching the sides of your oven. You may have noticed that your cakes rest on a nice metal rack in the center of oven and yet still get baked. :smallbiggrin:

[Theobod]

Knowledge (Engineering) or (Arcana), maybe (Planes); I would have accepted whichever was available of those, with Engineering having the lowest DC, then Arcana at+2-5 DC, and Planes a bit above that. Not a terrible call as given though, with the Dilettante around. I tend to give certain real-world Knowledge types a bit of leeway in 3.5/PF though because in many cases they are indeed covered by more than one area of expertise.

Personally I would have called for Knowledge: Nature to know the qualities of natural minerals rather than any of the above, Architecture and Engineering would be more for designing a buoyant boat after that has been established. Either way the statement concerning ovens still applies, check the rules for being close to lava, touching it is not really the issue here, proximity will leave you unconscious fairly sharpish.

[BowStreetRunner]

...check the rules for being close to lava...
Looking for a source on this. SRD only has this on lava effects (http://www.d20srd.org/srd/environment.htm#lavaEffects). The section on heat dangers above it might be relevant, but it doesn't specify how hot it would be that close to the lava. Sandstorm has quite a few references to lava, but I still don't see where it tells how hot it would be if you were that close.

[Gildedragon]

A salt - blue ice hull is bound to be good; blue ice melts as if it were steel, and it is bound to cool the air around it. The salt hull keeps the blue ice below softening temperature.

Riverine is bound to be a great insulator. Wall of force prevents contact heat transfer and the radiant heat gets absorbed by the volume of water within it

[Segev]

The point of riverine always eluded me. The water inside it is irrelevant to its physical properties. Why not just make things out of force?

[Theobod]

My guess is to provide it with some weight as force doesn't have any inherently.

[Gildedragon]

The pressure the riverine water is under is frankly ludicrous. A greatsword weighs 8lb or about 4kg, and has a volume of approximately 2300 ccs, or 2.3 lts which must accommodate 4lts of water. I don't know precisely how much but I know it takes a few hundred of tons per square inch to compress it by 1%. I ain't sure if a 50% compression wouldn't make it solid

[Honest Tiefling]

I'm mildly surprised no one has mentioned Knowledge (Alchemy) as a contender yet. I thought lighting things on fire was half of alchemy to begin with!


The point of riverine always eluded me. The water inside it is irrelevant to its physical properties. Why not just make things out of force?

It looks pretty? You could dye the water and then add in some metal dust to achieve an effect like those bottles sometimes sold on the street.

[Inevitability]

The point of riverine always eluded me. The water inside it is irrelevant to its physical properties. Why not just make things out of force?

1. Pure force is invisible and weightless. Armor and swords you can't see and barely feel might sound cool, but they're going to be difficult to handle.
2. Riverine force is different from 'regular' magical force and collapses onto itself if it isn't supported from within.
3. Without anything inside, a riverine sword wouldn't be heavy enough to seriously damage someone.

So if you must have something within the force walls, why water? Well, it's easily available and can easily be forced into certain shapes.

[Theobod]

That is probably the most comprehensive and well reasoned explanation I have heard and is now my head cannon. Is point two backed up anywhere for the naysayers?

[Gildedragon]

That is probably the most comprehensive and well reasoned explanation I have heard and is now my head cannon. Is point two backed up anywhere for the naysayers?

Riverine force is wall of force, explicitly stated in the book. Wall of force doesn't collapse in on itself so riverine ought'n't either.
The weight and visibility explanations make sense though and are how I've justified the stuff.


Re: Honest Tiefling Kn (alchemy) is in the same boat as Kn (thermodynamics) in that it isn't a canonical knowledge and thus unexpectable by players. Alchemy is covered by Craft.

[Honest Tiefling]

Except that Alchemy would be more prevalent in an assumed Medieval/Renaissance type setting. Unless they're making salt canoes in a more modern setting? That might explain how they got so much of it.

[ZamielVanWeber]

Marvelous Pigments can create foodstuffs which is how we got so much salt. I am pretty sure that Knowledge check was the DMS way of saying "no" to my suggestion of finding a poor thermal conductor with a high melting point. When the guy made the roll I started looking for candidates; there are better ones but they are not nearly as funny.

As for the actual roll it should have been Craft (Alchemy); it seems to be the most accurate, since it is the precursor to chemistry. Knowledge wise I would vote Architecture and Engineering.

[Deophaun]

Not the most efficient way to traverse lava. I prefer stretching a cloak over a large fire-resistant shield, soaking it with a decanter of endless water, and rocketing across the surface thanks to the wonders of the Leidenfrost effect.

[Inevitability]

Not the most efficient way to traverse lava. I prefer stretching a cloak over a large fire-resistant shield, soaking it with a decanter of endless water, and rocketing across the surface thanks to the wonders of the Leidenfrost effect.

You don't even need a Decanter: Prestidigitation can dampen objects for you.

[Theobod]

Steering may prove a tad difficult there but I guess that's what Ballence/Perform: Surfing/ Profession: Sailor is for ;)

[ace rooster]

Ok, I feel like I should point out that most salt would probably not be good for this, as 800C is not a high enough melting point against lava. That might be against some cooler ones, but most of the time not. Some fluorides would get you a couple hundred extra degrees, but not a safe margin.

Also, do you know if sodium chloride is soluble in silicates? Your canoe might simply dissolve, which would be embarrassing.

I would probably go with an asbestos lined titanium boat, possibly with a graphite layer to improve the structure.

Still, good times. :smallsmile:

[martixy]

The pressure the riverine water is under is frankly ludicrous. A greatsword weighs 8lb or about 4kg, and has a volume of approximately 2300 ccs, or 2.3 lts which must accommodate 4lts of water. I don't know precisely how much but I know it takes a few hundred of tons per square inch to compress it by 1%. I ain't sure if a 50% compression wouldn't make it solid

Fun physics facts that in no way belong in a D&D game:

First of all, water is an known as a mostly incompressible liquid. Insofar it does not remain a liquid when compressed.
Second, this is where phase diagrams (https://en.wikipedia.org/wiki/Phase_diagram) come in handy. Did you know that there are at least 15 different kinds of ice?
Technically speaking at room temperature under that kind of reputed pressure, there is absolutely no way that enclosed body of water can remain in liquid form.
The higher ices(e.g. ice-10, ice-11), whose crystals are forced into highly ordered and symmetric arrangements do actually have quite a high density(like 2.5g/cm3).

By definition you can't make a 4l volume fit into a 2l space(both are units of volume, it's a mathematical impossibility).
You can however fit 4kg of water into a 2.3l volume. You merely need enough pressure to produce a density ~75% greater than liquid water.

I do like Deophaun's train of thought though.

On the other hand, salt really does have a low melting point.
What you could have used is silicate-based ceramics, you know, what space vehicles use as re-entry heat shields.
I'd peg the intelligence check on that one at about DC100.

[atemu1234]

I'd suggest routing a river into the temple, is it below sea level?

[Inevitability]

I'd suggest routing a river into the temple, is it below sea level?

A Decanter of Endless water is probably faster and easier, and I'm fairly sure it's within WBL for the mentioned party.

[ZamielVanWeber]

Ok, I feel like I should point out that most salt would probably not be good for this, as 800C is not a high enough melting point against lava. That might be against some cooler ones, but most of the time not. Some fluorides would get you a couple hundred extra degrees, but not a safe margin.

Also, do you know if sodium chloride is soluble in silicates? Your canoe might simply dissolve, which would be embarrassing.

I would probably go with an asbestos lined titanium boat, possibly with a graphite layer to improve the structure.

Still, good times. :smallsmile:

Titanium cannot be created by Marvelous Pigments. Also I went with NaCl because it is funny and DnD lava is not hot (Resist Fire 1 stopped it initially, IIRC if Rules Compendium fixed that).

[Eisfalken]

Technically, you would need two skills: Craft (Alchemy) to know the chemical properties of salt, and either Craft (boatbuilding) or Knowledge (architecture & engineering) to figure out how to build a "boat" out of it (per Stormwrack).

[Eisfalken]

A Decanter of Endless water is probably faster and easier, and I'm fairly sure it's within WBL for the mentioned party.

Heck, forget that: something that repeatedly casts create water is probably cheaper. It can't do all the things the decanter can, but you only really need it here for the water to cool the lava.