Age of Heroes
(Str; Armor Penalty)
Always useful if you are thrown from the side of your galley by a passing god or the far more mundane issue of merely staying afloat.
Make a Swim check once per round while you are in the water. Success means you may swim at up to one half your speed as a full-round action or at one-quarter your speed as a move action. If you fail by four or less, you make no progress through the water. If you fail by five or more, you go underwater. If you are underwater, either because you failed a Swim check or because you are swimming underwater intentionally, you must hold your breath. You can hold your breath for a number of rounds equal to your Constitution score, but only if you do nothing other than take move or free actions. If you take a standard or full-round action, such as making an attack, the remainder of the duration for which you can hold your breath is reduced by one round. Effectively, a character in combat can hold their breath only half as long as normal. After that period of time, you must make a DC 10 Constitution check every round to continue holding your breath. Each round, the DC for that check increases by one. If you fail the Constitution check, you begin to drown. The DC for the Swim check depends on the water, as given on the table below. Each hour that you swim, you must make a DC 20 Swim check or take 1d6 points of non-lethal damage from fatigue.
A successful Swim check allows you to swim one quarter of your speed as a move action or one-half your speed as a full-round action.
Swim checks are subject to double the normal armor check penalty and encumbrance penalty. If you have the Athletic feat, you gain a +2 bonus on Swim checks. If you have the Endurance feat, you gain a +4 bonus on Swim checks made to avoid taking non-lethal damage from fatigue. A creature with a swim speed can move through water at its indicated speed without making Swim checks. It gains a +8 racial bonus on any Swim check to perform a special action or avoid a hazard. The creature always can choose to take 10 on a Swim check, even if distracted or endangered when swimming. Such a creature can use the run action while swimming, provided that it swims in a straight line.