Alissa could hold her breath for 16 + (Swimming+Willpower roll) turns.<br/>She can swim 6 + (Swimming+Strength roll) meters per turn.<br/>However after 2 + (Swimming+Strength roll) turns she begins to take fatigue stun damage... which seems really fast.  Hmm.  Maybe that is if just making the roll?<br/><br/>So she could hold her breath (assuming a straight 6 on the speed, no successes on the willpower roll, and ignoring the stun damage) for 96 meters.<br/><br/>Hmm.  I would think that either type could assist with movement, though the air one would probably be fairly noticeable doing so.