Questions on Swimming...

[smetzger]

Swimming without a swim speed requires a successful swim check and then your movement is 1/4.

1) If you have a movement of 30'/4 = 7.5. Should this be rounded up to 10' our down to 5'?

2) Rules indicate that only fire spells behave differently underwater. If your under the influence of a fly spell... can you 'fly' underwater?
Would that negate the need for a swim check?
What would your speed be?

[Darg]

Swimming without a swim speed requires a successful swim check and then your movement is 1/4.

1) If you have a movement of 30'/4 = 7.5. Should this be rounded up to 10' our down to 5'?

2) Rules indicate that only fire spells behave differently underwater. If your under the influence of a fly spell... can you 'fly' underwater?
Would that negate the need for a swim check?
What would your speed be?

1) It gets rounded down to 5', but if you use a full round action then half your speed is 15'.

2) Flight requires air. Water displaces air. You can fly 'under' water if you can somehow create or find a large air bubble in or under water. You require a swim speed or swim check to move in/through water.

[Biggus]

Rules indicate that only fire spells behave differently underwater.

Where are the rules about that? I'm currently running an underwater section of an adventure and I was wondering how magic worked there.

[Jay R]

If you are swimming at 7.5 feet per round, then in two rounds, you should go 15 feet. The DM should make a judgment call about where you are after the first round.

[hamishspence]

Where are the rules about that? I'm currently running an underwater section of an adventure and I was wondering how magic worked there.

The DMG.

Equivalent section of the SRD:

https://www.d20srd.org/srd/wilderness.htm#underwaterCombat

Fire
Nonmagical fire (including alchemist’s fire) does not burn underwater. Spells or spell-like effects with the fire descriptor are ineffective underwater unless the caster makes a Spellcraft check (DC 20 + spell level). If the check succeeds, the spell creates a bubble of steam instead of its usual fiery effect, but otherwise the spell works as described. A supernatural fire effect is ineffective underwater unless its description states otherwise. The surface of a body of water blocks line of effect for any fire spell. If the caster has made a Spellcraft check to make the fire spell usable underwater, the surface still blocks the spell’s line of effect.

[Melayl]

1) It gets rounded down to 5', but if you use a full round action then half your speed is 15'.

2) Flight requires air. Water displaces air. You can fly 'under' water if you can somehow create or find a large air bubble in or under water. You require a swim speed or swim check to move in/through water.

Air acts like a fluid. You can, indeed, "fly" through water as you would through air. There are various water birds that do exactly that while diving and hunting for fish.

https://howthingsfly.si.edu/ask-an-explainer/could-you-fly-plane-underwater-if-it-had-all-water-proof-features

If your flight does not involve using wings, why would there be any problem "flying" underwater? Why would it be different than flying in the air?

[Fouredged Sword]

If I was DM I would allow players to keep their fly speed underwater, but it would still require a swim check and impose the normal 1/4 reduction if used to swim. This would allow something with a very high fly speed like, for example a big dragon with a 200ft fly speed and 40ft move speed, to swim very fast compared to it's relatively normal move speed, being able to swim 50 feet per action rather than 10.

[Darg]

Air acts like a fluid. You can, indeed, "fly" through water as you would through air. There are various water birds that do exactly that while diving and hunting for fish.

https://howthingsfly.si.edu/ask-an-explainer/could-you-fly-plane-underwater-if-it-had-all-water-proof-features

If your flight does not involve using wings, why would there be any problem "flying" underwater? Why would it be different than flying in the air?

Because movement through water requires a swim speed or a swim check (https://www.d20srd.org/srd/wilderness.htm#aquaticTerrain). Flight also has aspects that are negated by being in water (can't hover for example so suffer the rules for falling). Mechanically speaking flight in water is contradictory and not fleshed out well enough to be RAW.

Besides, if we want to get too irl technical you don't actually touch anything and therefore everything is actually flying.

Mechanically speaking, those birds are unable to "fly" underwater as quickly as they can above. Representatively they would probably have a swim speed to represent their natural ability to move through water.


If I was DM I would allow players to keep their fly speed underwater, but it would still require a swim check and impose the normal 1/4 reduction if used to swim. This would allow something with a very high fly speed like, for example a big dragon with a 200ft fly speed and 40ft move speed, to swim very fast compared to it's relatively normal move speed, being able to swim 50 feet per action rather than 10.

Dragons you find in or around water already have a swim speed of 60ft (40 for green).

TBQH, allowing flying underwater is exactly like allowing swimming through the air. If you allow one, there is no logical reason to prevent the other.

[Wintermoot]

TBQH, allowing flying underwater is exactly like allowing swimming through the air. If you allow one, there is no logical reason to prevent the other.

This^^^^ Forget real world physics or how you think it SHOULD work in real life. Fly speed is already the most powerful movement type in the game, there's no reason to make it more powerful. Creatures/characters with Swim (for water) and Burrow (for earth) deserve to have their special too.

So, no, as DM I would never let you use your fly speed to "fly" through water. And I firmly believe that is RAI.

[Batcathat]

TBQH, allowing flying underwater is exactly like allowing swimming through the air. If you allow one, there is no logical reason to prevent the other.

Depends on the method of flying, I think. Wings or jet propulsion wouldn't work the same way under water but if it's done purely through some sort of magical levitation, there's not really any reason for it not to work under water (similar to how I could use my hand to move something around, whether it's in the air or under water). It's neither fair nor balanced, of course, but things involving D&D magic rarely are.

[Biggus]

2) Flight requires air. Water displaces air. You can fly 'under' water if you can somehow create or find a large air bubble in or under water. You require a swim speed or swim check to move in/through water.

This appears to be correct. The MM (p.312) defines flight as the ability to "move through the air".


The DMG.

Equivalent section of the SRD:

https://www.d20srd.org/srd/wilderness.htm#underwaterCombat

Fire
Nonmagical fire (including alchemist’s fire) does not burn underwater. Spells or spell-like effects with the fire descriptor are ineffective underwater unless the caster makes a Spellcraft check (DC 20 + spell level). If the check succeeds, the spell creates a bubble of steam instead of its usual fiery effect, but otherwise the spell works as described. A supernatural fire effect is ineffective underwater unless its description states otherwise. The surface of a body of water blocks line of effect for any fire spell. If the caster has made a Spellcraft check to make the fire spell usable underwater, the surface still blocks the spell’s line of effect.

Ah, thank you. *reads section* So the rules don't say that only fire spells work differently underwater, they just don't specifically mention its effect on any other spells?

[loky1109]

Air acts like a fluid. You can, indeed, "fly" through water as you would through air. There are various water birds that do exactly that while diving and hunting for fish.

https://howthingsfly.si.edu/ask-an-explainer/could-you-fly-plane-underwater-if-it-had-all-water-proof-features

If your flight does not involve using wings, why would there be any problem "flying" underwater? Why would it be different than flying in the air?
Birds that you talk about obviously have swim speed.
You know, not every flying creatures can use wings for swim. Most of them can't.

[Melayl]

Birds that you talk about obviously have swim speed.
You know, not every flying creatures can use wings for swim. Most of them can't.

Actually, according to physics, any winged creature *can* use their wings to fly through water. Air and water are both fluids, although water is more viscous than air. It might be more difficult for them to fly in water, and they might panic and not use their wings properly, but wings do work exactly the same in the air as in water.

As for why you can't swim through the air, again, water is more viscous and therefore has more resistance than air. Also, air is lighter than water, and most things that could be boyant in water will not be boyant in air. Less resistance to push against + less boyancy = can't swim.

I realize that "mechanically" it isn't spelled out in the rules, but it seems to be common sense to me. As a DM I'd certainly follow what I see as common sense, but you can do whatever you choose to do.

[loky1109]

Actually, according to physics, any winged creature *can* use their wings to fly through water.

No. You are wrong. I mean, of course they can. And you can, and cats can, but most of wings are not disigned by evolution for swimming.


Air and water are both fluids.
Air isn't. It is gas. Gases and liquids have many differents. More than you think. Swim and fly are different tasks and they require different technical solutions.

Fly in the air in most parts not based on "push air back and push self forward". Lifting force gets from difference between pressure under and above the wing. Flying wings optimized for this task and when they push, they push down, not back. In the water you need exactly pushing (back, not down). And not every wing can do this good in so viscous surroundings. Most just broke. Fully or only feathers.

Plus, big area of wings needed in air in water is only obstacle. Yes, you push yourself forward when swing back, but when you'll move wings forward to ready for next swing you'll stop yourself and push you back.

And I didn't tell about insect's wings ..


but it seems to be common sense to me.
This isn't any form of attack, but you are bad in physics as I can see and because of it your common sense doesn't work good in this field.

[Wintermoot]

common sense can cut both ways on issues of "what's good for the game" vs "what's realistic"

for the game, imagine you have two players, one who has a flight speed of 60' and one who invested in a swim speed of 60'. Now imagine how that second player feels when you as the DM say "oh both players have 60' speed through water". He feels, rightly so, like it's unfair. I guarantee no future players for that DM will ever invest in swim speed or swim powers. So common sense, as far as what's good for the game, is very clearly in the "flight speed does not equal swim speed"

I also tend to disagree with you on "wings work as well underwater" in real life either. Flying birds that "swim" underwater are all based on speed diving where they fold their wings in and dive for fish. Or they are something like ducks where they are using their feet for swimming, not their wings.

Wings aren't like paddles. With paddles you use the paddle vertically on the stroke to push against the water to provide movement, then you lift the paddle out of the water or at least turn it horizontally to limit surface area on the backstroke in order to limit the reverse surface area. Most creatures with wings either don't ahve the correct musculature for that, or the feathers don't have water-proofing (like Ducks) to protect them from the water and to make them impermeable to the water when "stroking" against it.

So if you wanted to use wings as flippers you'd have to have specialized wings and the musculature and training to use them the right way. Which is considerably different than how you use them to fly through the air.

[Melayl]

No. You are wrong. I mean, of course they can. And you can, and cats can, but most of wings are not disigned by evolution for swimming.


Air isn't. It is gas. Gases and liquids have many differents. More than you think. Swim and fly are different tasks and they require different technical solutions.

Fly in the air in most parts not based on "push air back and push self forward". Lifting force gets from difference between pressure under and above the wing. Flying wings optimized for this task and when they push, they push down, not back. In the water you need exactly pushing (back, not down). And not every wing can do this good in so viscous surroundings. Most just broke. Fully or only feathers.

Plus, big area of wings needed in air in water is only obstacle. Yes, you push yourself forward when swing back, but when you'll move wings forward to ready for next swing you'll stop yourself and push you back.

And I didn't tell about insect's wings ..


This isn't any form of attack, but you are bad in physics as I can see and because of it your common sense doesn't work good in this field.

I appreciate that you aren't attacking my comments. Please understand that I'm not trying to attack you, either. However, you do have some things incorrect in your post.

Physics says both air and water are fluids. Yes, one is a gas and one is a liquid. Both, by definition of physics, are fluids, due to the way they move. So is plasma.

https://courses.lumenlearning.com/physics/chapter/11-1-what-is-a-fluid/

https://www.windows2universe.org/teacher_resources/air_fluid.html#:~:text=Any%20substance%20that%20fl ows%20is,can%20be%20classified%20as%20fluids.

I do admit and regret that I was not complete in my statements earlier. It does take more force to fly underwater, and some wings might not be able to handle such forces. Some wings might not propel very quickly, and some might even break under such force. So, I was partially incorrect in saying that *all* winged creatures could fly underwater as they do in the air.

However, the *mechanics* of flight, *how* the wings would need to move, is the same as it would be in the air. This is because both air and water are fluids, and aerodynamics works the same in both. See the above links.

[Darg]

Movement Modes: Creatures may have modes of movement other than walking and running. These are natural, not magical, unless specifically noted in a monster description.

Burrow: A creature with a burrow speed can tunnel through dirt, but not through rock unless the descriptive text says otherwise. Creatures cannot charge or run while burrowing. Most burrowing creatures do not leave behind tunnels other creatures can use (either because the material they tunnel through fills in behind them or because they do not actually dislocate any material when burrowing); see the individual creature descriptions for details.

Climb: A creature with a climb speed has a +8 racial bonus on all Climb checks. The creature must make a Climb check to climb any wall or slope with a DC of more than 0, but it always can choose to take 10 (see Checks without Rolls, page 65 of the Player ’s Handbook), even if rushed or threatened while climbing. The creature climbs at the given speed while climbing. If it chooses an accelerated climb (see the Climb skill, page 69 of the Player ’s Handbook), it moves at double the given climb speed (or its base land speed, whichever is lower) and makes a single Climb check at a –5 penalty. Creatures cannot run while climbing. A creature retains its Dexterity bonus to Armor Class (if any) while climbing, and opponents get no special bonus on their attacks against a climbing creature.

Fly: A creature with a fly speed can move through the air at the indicated speed if carrying no more than a light load; see Carrying Capacity, page 161 of the Player ’s Handbook. (Note that medium armor does not necessarily constitute a medium load.) All fly speeds include a parenthetical note indicating maneuverability, as follows:
—Perfect: The creature can perform almost any aerial maneuver it wishes. It moves through the air as well as a human moves over smooth ground.
—Good: The creature is very agile in the air (like a housefly or a hummingbird), but cannot change direction as readily as those with perfect maneuverability.
—Average: The creature can fly as adroitly as a small bird.
—Poor: The creature flies as well as a very large bird.
—Clumsy: The creature can barely maneuver at all.
A creature that flies can make dive attacks. A dive attack works just like a charge, but the diving creature must move a minimum of 30 feet and descend at least 10 feet. It can make only claw or talon attacks, but these deal double damage. A creature can use the run action while flying, provided it flies in a straight line. For more information, see Tactical Aerial Movement, page 20 of the Dungeon Master’s Guide.

Swim: A creature with a swim speed can move through water at its swim speed without making Swim checks. It has a +8 racial bonus on any Swim check to perform some special action or avoid a hazard. The creature can always can choose to take 10 on a Swim check, even if distracted or endangered. The creature can use the run action while swimming, provided it swims in a straight line.

There is no exception that a fly speed allows a creature to fly in water or through any other substance.

[loky1109]

Physics says both air and water are fluids. Yes, one is a gas and one is a liquid. Both, by definition of physics, are fluids, due to the way they move. So is plasma.

I see. My mistake. There aren't merged term in my language, only separate gas and liquid, so I was unfamiliar with this word.


Some wings might not propel very quickly, and some might even break under such force
Not "some" but "most".


However, the *mechanics* of flight, *how* the wings would need to move, is the same as it would be in the air.
I can't agree. In water you don't need lifting force - you take it from buoyancy. In air you definitely need it. Even if we'll not look at the water resistance, bird's wings give inappropriate resulting vector of force. Birds push themselves more up and less forward, swimmers need to push themselves forward only (or at least much less up). And birds can't change it. Physiologically.

And even we say that all birds can "fly" through water... Well. Greater part of flyers are insects. Incomparably greater. More than 99%. And most of them can't "fly" in water at all. Even theoretically.
Butterflies for example fly creating air depression between upper surfaces of their wings at each stroke. In water this don't work.
Dragonflies and hymenopterans do hundreds strokes in second - in water no way do that. I can continue.



This is because both air and water are fluids, and aerodynamics works the same in both.
Look here:
https://en.wikipedia.org/wiki/Fluid_dynamics
Aerodynamics and hydrodynamics are different disciplines. And this is with reason.

[Melayl]

From what I've read (and I am certainly not a physicist so I could be wrong), the differences between the two are negligible at below sonic/supersonic speeds.

Regardless of all of that, it is certainly 100% within RAW to rule that flight does not work underwater.

I would say it is also reasonable for a GM to rule that flight could work underwater. Entirely up to your GM to decide.

[smetzger]

Ah, thank you. *reads section* So the rules don't say that only fire spells work differently underwater, they just don't specifically mention its effect on any other spells?

P. 149 of the Rules Compendium...
"Magical effects are unaffected except for those that require attack rolls, which are treated like any other attacks, and fire
effects (see below)."

Rules Compendium p. 149, 141 and Swim skill check cover most stuff about underwater.
Then there are spells: water breathing, freedom of movement, and swim.

[Fouredged Sword]

I believe there is a more detailed section covering how spells work underwater in Stormwrack. I may be wrong, but generally if you want to have an adventure anywhere that's wet its a good book to look through.

[rel]

Swimming without a swim speed requires a successful swim check and then your movement is 1/4.

1) If you have a movement of 30'/4 = 7.5. Should this be rounded up to 10' our down to 5'?

2) Rules indicate that only fire spells behave differently underwater. If your under the influence of a fly spell... can you 'fly' underwater?
Would that negate the need for a swim check?
What would your speed be?

The RAW calls out flight as movement through air and swimming as movement through water.
Flying through water would be a houserule.

[Jay R]

There's no point continuing to argue about flying through water. Some people think it should work; some people don't.

So the DM at each game will make a ruling for that game. In my game, flying doesn't work underwater. [But also, I haven't run an underwater adventure in this century.]

Ask your DM. Making rulings is their job.