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View Full Version : Thought - Walking on Water? (Mundane)



Nero24200
2009-12-28, 06:20 PM
Inspired by
this scene (http://www.youtube.com/watch?v=tZWLpxTfnB8) shown in an earlier topic, it got me thinking of a few ways of making the "epic feel" of high level combatants, such as cutting throw objects like trees and running fast enough to move on water.

This is where the question comes in. Just how fast would a character need to be to run on water? To my knowledge, no animal can run on water, so such a person would at least need to be faster than any animal to acomplish such a feat (if it would even be possible).

Signmaker
2009-12-28, 06:24 PM
There's an MiC item that does this, as a swift action movement. As for velocity and mundaneness, no clue. That would have to take in to account surface tension vs. weight displacement.

SurlySeraph
2009-12-28, 06:24 PM
The basilisk, aka Jesus Christ Lizard, is a real-world animal that can run on water. (http://www.youtube.com/watch?v=45yabrnryXk) Water striders, a common insect, can also walk on water, but the physics that allow them to do so wouldn't allow larger animals to do the same.

Djinn_in_Tonic
2009-12-28, 06:25 PM
Inspired by
this scene (http://www.youtube.com/watch?v=tZWLpxTfnB8) shown in an earlier topic, it got me thinking of a few ways of making the "epic feel" of high level combatants, such as cutting throw objects like trees and running fast enough to move on water.

This is where the question comes in. Just how fast would a character need to be to run on water? To my knowledge, no animal can run on water, so such a person would at least need to be faster than any animal to acomplish such a feat (if it would even be possible).

It's not really a matter of speed: weight, distribution, and surface area are all part of it. The water strider is an insect that can walk on water through the correct distribution of its weight against the water tension. I believe the Basilisk Lizard can also walk on water for a short time (run on it, rather), but I'm not sure why that's the case.

Edit: Damn ninjas... :smallbiggrin:

bosssmiley
2009-12-28, 06:26 PM
This is where the question comes in. Just how fast would a character need to be to run on water? To my knowledge, no animal can run on water, so such a person would at least need to be faster than any animal to acomplish such a feat (if it would even be possible).

You don't need the speed of a Jesus Lizard to run on water. All you have to do is intimidate the water so badly it stays exactly where you tell it to (ie: underfoot).

Signmaker
2009-12-28, 06:27 PM
Edit: Damn ninjas... :smallbiggrin:

I was a good minute ahead, though without the creature references.

Ravens_cry
2009-12-28, 06:27 PM
I asked this question on a physics forum, and the basic answer was if you could run as fast as a barefoot waterskier being towed behind a boat, you could run on water.

olentu
2009-12-28, 06:28 PM
Well in D&D they would need to be a DC90 balance I believe check fast to walk on water.

jseah
2009-12-28, 06:28 PM
You don't have to be fast. You just to exert an equal downwards force on the water surface as your weight.

In practice, that usually means the water doesn't stay there for long.

So it'll look more like you're hopping on water, rather than running on it.

Trailing small watery explosions while you're at it.

Let's say each hop takes 0.5 seconds, and you only touch the water for 0.05 seconds. If we assume the force you exert is equal over time (it's not), the minimum force you need to stay up is at least 10 times your body weight.
And that's not considering that you'll generate a shockwave in the water body with pressure equals to 10 times your weight.

The energy requirements are just insane.

zzz... need to calculate the speed of your foot on water to generate that kind of force.

Ravens_cry
2009-12-28, 06:31 PM
You don't have to be fast. You just to exert an equal downwards force on the water surface as your weight.

Possible nitpick. Wouldn't that be upwards force??? Because we normally do the whole 'exert a downward force equal to our weight', I would think.
Hmmm. . .this problem, like so many others, can be solved with explosives.

deuxhero
2009-12-28, 06:33 PM
A Monk ACF from it's wet outside.

jseah
2009-12-28, 06:36 PM
^you exert a downwards force on the water, it exerts an upwards force back on you.

If it's equal to your weight, you stay up.

When you step into a pond or puddle, you don't exert your full body weight on the water. It moves aside before that and the leftover force goes into making you plunge in.
***This is a simplification. I don't know the equations for the actual forces.

That said, the earlier conclusion, running as fast as a water skier, is about right.

Stegyre
2009-12-28, 06:39 PM
Possible nitpick. Wouldn't that be upwards force??? Because we normally do the whole 'exert a downward force equal to our weight', I would think.
Hmmm. . .this problem, like so many others, can be solved with explosives.Check out normal force (http://en.wikipedia.org/wiki/Normal_force).

Physics is your friend. (Well, not the electromagnetics part; that's a b-)

The Dark Fiddler
2009-12-28, 06:43 PM
You don't need the speed of a Jesus Lizard to run on water. All you have to do is intimidate the water so badly it stays exactly where you tell it to (ie: underfoot).

DC 100 Intimidate Check.

Quick, get the optimizers and give them a Level 1 Commoner! Let's see how quickly they can get it. :smallamused:

taltamir
2009-12-28, 07:17 PM
http://www.d20srd.org/srd/epic/skills.htm
it is a DC90 balance check to walk on water without magic.

bibliophile
2009-12-28, 09:01 PM
You could wear large boat like shoes.

If a person is 150 lbs, they need to displace about 2.5 cubic feet of water. If your boat shoes were approximately half-cylinders (so that the two shoes together made a cylinder) a length of 1.5 feet and diameter of 1.5 feet would keep you afloat. And you;d have to walk funny.

Boat shoes are not however, particularly epic.

Volos
2009-12-28, 09:21 PM
There are sandals that allow you to ballance on a wall or an unstable surface like snow or water.

Pharaoh's Fist
2009-12-28, 11:36 PM
Chuck E. Cheese could probably move fast enough.

SurlySeraph
2009-12-28, 11:40 PM
That's the Ruby Knight Windicator, right? Doesn't work anymore. Errata nixed Persistent Footsteps of the Divine.

deuxhero
2009-12-28, 11:44 PM
You could wear large boat like shoes.


Never watch Mythbusters I take it?

Yukitsu
2009-12-28, 11:44 PM
IIRC, there's a swordsage stance that lets you walk on water, or even on air. Supernatural abilities, but given the source is anime, I'd take it. I believe the water walk was a 5th level manuever, meaning a swordsage can get it at 9.

The Glyphstone
2009-12-28, 11:51 PM
That's the Ruby Knight Windicator, right? Doesn't work anymore. Errata nixed Persistent Footsteps of the Divine.

Chuck still works to a point. He just can't break the speed of light anymore.

deuxhero
2009-12-28, 11:53 PM
What? show me this build!

Glimbur
2009-12-28, 11:59 PM
There's a soulmeld that lets you walk on water. Cerulean Sandals iirc.

Mando Knight
2009-12-29, 12:08 AM
Never watch Mythbusters I take it?

Yeah... you need ridiculous balancing capabilities, and each shoe needs to be able to support your entire weight.

bibliophile
2009-12-29, 12:11 AM
Yeah... you need ridiculous balancing capabilities, and each shoe needs to be able to support your entire weight.

Hmm, good point.

It's difficult, but not impossible.

Harperfan7
2009-12-29, 02:49 AM
What's the Jackie Chan movie where he goes to Australia? There's a fight scene in the penthouse of a very tall hotel where he gets across a pool by run-stepping on a little child-water-ring-floater-thing to the other side. He actually did it, it wasn't special effects.

I realize thats not the same, but you'd think a D&D character could do it eventually.

In the game Oblivion, if you have 100 in your acrobatics skill you can continually jump across water.

The swiftblades 9th level ability can allow you to run over water.

AirGuitarGod32
2009-12-29, 03:22 AM
There's an either balance or tumble check to walk/leap off a wall. Maybe someone can come up with one for walking on water.

Killer Angel
2009-12-29, 04:19 AM
There's an either balance or tumble check to walk/leap off a wall. Maybe someone can come up with one for walking on water.

What a good idea! I really wonder who will ever do such a thing... :smallamused:


Well in D&D they would need to be a DC90 balance I believe check fast to walk on water.


http://www.d20srd.org/srd/epic/skills.htm
it is a DC90 balance check to walk on water without magic.

Kobold-Bard
2009-12-29, 12:29 PM
A Monk ACF from it's wet outside.

I like it, and is even moderately useful, unlike Slow Fall which is beyond pointless.

Jayabalard
2009-12-29, 01:00 PM
This is where the question comes in. Just how fast would a character need to be to run on water? To my knowledge, no animal can run on water, so such a person would at least need to be faster than any animal to acomplish such a feat (if it would even be possible).there are plenty of animals that can, but they're all either EXTREMELY light, or very light + very fastor use special effects


The water Strider (http://www.youtube.com/watch?v=_d5tUBFaNL0&feature=related) or pond skater is an insect that can do it.

There's the Jesus lizard (http://www.youtube.com/watch?v=Qhsxo7vY8ac).

And last but not least there's a certain breed of Tiger (http://www.youtube.com/watch?v=FZ1st1Vw2kY&NR=1&feature=fvwp) that can do it.

Zom B
2009-12-29, 01:13 PM
What? show me this build!

http://community.wizards.com/go/thread/view/75882/19861942/Chuck_E._Cheese

Jayabalard
2009-12-29, 02:07 PM
You don't have to be fast. You just to exert an equal downwards force on the water surface as your weight. You're already exerting a force equal to your weight downward... that's what weight means.


Check out normal force (http://en.wikipedia.org/wiki/Normal_force).

Physics is your friend. (Well, not the electromagnetics part; that's a b-)I'm not really sure that's a sufficiently complete model when talking about water; you need to be looking at how surface tension works. There are limits to how much force the surface of the water can exert on an object based on a number of factors (size, and time primarily iirc).