what would be the rules for casting while swimming or underwater.
character falls out of a boat. he is swimming... attempts to cast a spell: whats the concentration check (assume rough water)
same character fails his swim check and is now underwhater holding his breath: whats the concentration check, whats the penalty to trying to cast under whiter? (normal standard action penalty?)
Same character reaches the bottom of the water and is no longer attempting to swim but is still completely submerged: what is the concentration? can they cast while submerged without immediatly drowning?
The Answer you are looking for, can be found in Player Hand Book, page 432 under Spellcasting Underwater entry.