Drowning Rules and House Rules

[ArcanaGuy]

Hello, everyone! My first post on the forums, figured I've lurked enough threads that I should probably join, especially since it occurred to me that you might help me with a problem of mine.

I'm a longtime DM for 3.0, but recently I started a new campaign with some new players, and the subject for this game was 'seafaring'. (to which all my players joyfully cried, "Yay, we can be pirates!") And I dunno why this didn't occur to me before someone jumped into the water, but I had never had to worry about drowning before.

So I looked it up and saw ... that an average person can breath underwater for 2 minutes (assuming combat round = 6 seconds) no matter what he's doing without making a check.

Now, that might be a bad assumption. My group has assumed that for a long time, but I can't find anything in the rules that says *why* we assume that. But regardless! It seems odd to me that drowning happens in the same amount of time no matter what you're doing... so I was wondering if there are any supplements that change these rules, or house-rules that worked particularly well?

My own on-the-spot decision was that staying still took up 1 round of air, being active automatically used up 2 rounds of air, and any especially difficult activity (crawling over the sharply barnacle-encrusted underside of the ship, thus taking damage) caused a fortitude save versus 10+damage or equivalent DC or else lose a third round's worth of air.

[TuggyNE]

The relevant rule is actually in the Swim skill description.
You can hold your breath for a number of rounds equal to twice your Constitution score, but only if you do nothing other than take move actions or free actions. If you take a standard action or a full-round action (such as making an attack), the remainder of the duration for which you can hold your breath is reduced by 1 round. (Effectively, a character in combat can hold his or her 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 1. If you fail the Constitution check, you begin to drown.

[ArcanaGuy]

Ha-HA! My on-the-fly was pretty much on the mark! Thank you, very much.