Check: A successful Swim check allows the character to swim one-quarter of the character's speed as a move-equivalent action or one-half the character's speed as a full-round action. Roll once per round. If the character fails, the character makes no progress through the water. If the character fails by 5 or more, the character goes underwater and starts to drown.

If the character is underwater (whether drowning or swimming underwater intentionally), the character suffers a cumulative –1 penalty to the character's Swim check for each consecutive round the character has been underwater.

The DC for the Swim check depends on the water:

Each hour that the character swims, make a Swim check against DC 20 or take 1d6 points of subdual damage from fatigue.

Special: Instead of an armor check penalty, the character suffers a penalty of –1 for each 5 pounds of gear the character is carrying or wearing.