Underwater Spellcasting

[Sacrosanct]

I should have expanded upon my thoughts.

Changes to the way spells work is fine (and can add to the fun). But, they need to be communicated IRL to the player in a timely manner (not necessarily before the first water adventure, depending). And they need to be thought through so that a roughly equivalent set of changes are made to all the character classes. Not that every character or class has to be exactly equal, but so that all characters are still fun to play.

I do agree that a genius level PC would have a good idea how his or her spells would work before actually doing them. So yes, the DM should let the player know and give them that list.

 

[Blue]

Thanks [MENTION=15700]Sacrosanct[/MENTION]. While I don't agree with 100% of them a lot of the effects give a good feel.

Quite useful, I'm running a two player sea/undersea campaign with a Triton paladin and a sea-shanty human bard. And their pet axolotl named Kracken.

 

[Sword of Spirit]

I’d just apply advantage or disadvantage to spell attack rolls and saves when it makes sense, remembering that things are held together by magic as much as physics. So maybe you have disadvantage on attacks with fire bolt due to the difficulty of it moving through the medium. But then again, creatures without swim speeds have a harder time dodging, so maybe it evens out. Maybe lightning bolt (held together by magic) travels well through the medium and imposed disadvantage on saving throws , while the super-heated water from a fireball doesn’t substantially change anything.

But really, you can spin things multiple different ways, so it’s fairly easy to say spellcasting works normally (maybe described with different visual effects for fun), unless you specifically want it to work differently.

 

[Bobble]

What are the rules, if any, regarding underwater spellcasting? I have looked through the books and couldn't find anything on the subject. Am I just missing something?

Look in the 1st Ed DMG

 

[LordEntrails]

I do agree that a genius level PC would have a good idea how his or her spells would work before actually doing them. So yes, the DM should let the player know and give them that list.

*shrugs* maybe. I've known/know "genius intellects" (as defined by Mensa). Doesn't mean they have much common sense or can extrapolate. Some have intellects that are very narrow and I can easily see that a 1st level wizard with a genius intellect would have no practical idea of how that would effect his spells if cast underwater. Lots of variables, just another situation for a DM to make a ruling on based upon their understanding.

 

[coolAlias]

Assuming we're talking about 5e here, I could only really find 3 explicit rules (see 1 - 3 below), two of which pertain to spell components and don't mention water at all but that do raise important points.

I've added a bunch of questions you may want to consider relating to each point, and several others have given some good ideas about how spells or material components might not work as expected.

1. Creatures and objects that are fully immersed in water have resistance to fire damage. (PHB 198)

- As such, I would suggest avoiding any further penalties to fire magic.

- Recall also that resistances from multiple sources do not stack, so a demon with fire resistance also fully submerged in water only halves the fire damage once.

2. A character who is gagged or in an area of silence can't cast a spell with a verbal component. (PHB 203)

- Is a character considered "gagged" when underwater?

* What if they have a swim speed? See for example attacking with melee weapons.

* What if they can breathe underwater?

- See also https://rpg.stackexchange.com/quest...-be-cast-underwater-if-the-caster-cant-breath

3. A character must have free use of at least one hand cast a spell with a somatic component. (PHB 203)

- Normally, a character can move and cast a spell at the same time; does swimming always require the use of both arms and hands, and if so, does that preclude casting somatic spells and moving in the same turn?

* Would the above ruling apply equally to Material components? What if it's a focus?

4. Assuming a spell is successfully cast, there do not appear to be any rules indicating that the spell effect will deviate from the spell description, regardless of whether that spell is cast in water or air unless otherwise specified by the spell itself. Thus, casting Shocking Grasp or Lightning Bolt while underwater behaves exactly as written, not electrocuting nearby creatures as real-world physics might otherwise suggest.

- Will this be the case for all spells, or will some be subject to physics?

* For example, fog cannot form in water; will the spell Fog Cloud simply fail if cast underwater, or will it work because "magic"?

- See https://rpg.stackexchange.com/questions/95717/what-happens-when-you-cast-fireball-under-water

- See https://rpg.stackexchange.com/questions/136108/what-happens-to-lightning-spells-underwater

Additonal thought: if the target of a spell is fully immersed in water and the spellcaster is not, does the water count as cover or concealment? See e.g. https://rpg.stackexchange.com/questions/107741/can-you-cast-spells-through-water

 

[cbwjm]

I would probably look at earlier editions for ideas. I'd make fire spells completely ineffective when cast underwater (I'm aware of the fire resistance rule mentioned above), spells that form clouds wouldn't work, ongoing acid damage is neutralised when surrounded by water. Lightning effects in earlier editions instead created a radius when forming which would be quite dangerous for the wizard casting lightning bolt since they would be at the centre of the burst.

Otherwise, I'd look at spells on a case by case basis, perhaps when the wizard player is memorising spells so that they can choose something else if desired, and then mark down the effects for later consistency.

I might be tempted to use 3e's method that required a spellcraft (arcana?) check to cast a fire spell successfully underwater (instead turning it to superheated steam) so that a wizard can still throw their fireball spell.

 

[digitalelf]

I would probably look at earlier editions for ideas.

The 2nd Edition AD&D book "Of Ships and the Sea" devotes several chapters on undersea adventuring; yes, including casting spells underwater, complete with how the environment effects spell components.

Yeah, it's 2nd edition, but it should be easy to make the conversions to 5th edition on the fly if need be.

 

[Li Shenron]

What are the rules, if any, regarding underwater spellcasting?

Without specific rules in 5e, spellcasting works normally underwater.

There are no penalties of any kind such as disadvantage on the spellcaster's possible attack roll or advantage to the target's saving throw, and there are no concentration checks necessary.

You can normally cast a spell that has verbal, somatic or material components underwater. Yes, also verbal component, because you can speak underwater even if you cannot breathe.

The game says nothing in terms of rules about the level of precision required by verbal/somatic components. There is some fluff text about "intricate gestures" and "specific pitch and resonance", but there is absolutely no rule saying when the circumstances make it impossible to cast, except the specific cases of being gagged or silenced for verbal, and not having a free hand for somatic. Therefore, everything else is up to the DM to house rules.

 

[Shiroiken]

I've already done an underwater encounter where the party was spellcasting. The biggest issue I imposed was losing rounds of holding your breath by casting spells with verbal components. They were in a long underwater tunnel with a water weird in the middle, and one of the characters almost didn't make it to the end because he cast 2 verbal spells during the fight. Of course, none of my players used fire, lightning, or acid damage spells, so I didn't need to make any kind of adjudication on the spell effects.