Jeremy
Explorer
Uller said:Can the character speak with a strong voice under water?
Yes. This part I've personally verified. Can it be understood by others? No. Is that necessary? Unknown.
Uller said:As for material components...that probably depends upon the component:
A gem?...not affected by water.
A strand of spider web? Spiders spin webs under water...the only question is, can the caster get a hold of it in water? I'd say it can work if the caster got it in his hand prior to going in the water.
Dust? I've never seen wet dust.
A drop of acid? It would instantly be diluted to the point that it was no longer acidic...
etc.
Wow.. I don't envy you the task of micromanaging that if you ever run into underwater combat.
As I said, the only official rules on the subject state that spells work fine underwater except for fire spells which require a spellcraft check to work. If you want to make it more complicated or difficult, go right ahead. Though examining the effectiveness of every component on a case by case basis might be a bit overkill.
It'd be easier to state spells with a V component require this spell or have this chance of failure, spells with a S component require this spell or have this chance of failure, and/or spells with a M component require this spell or have this chance. That way you can pick and choose and make it as uncomplicated or as "realistic" as you like without bogging down the game and making what would be an exciting cinematic and very different encounter and excercise in looking up information in books, statistics, probablilities and number crunching and loosing all the fun.
Of course, my personal opinion is that the spells take care of it, but if you do run it your way, you may need a simplifying mechanic.