Drowning

[Seven]

Any thought of adding rules for this somewhere?
It seems pretty common.
Characters in armor fall in a pit or a moat?

[Snarkythekobold]

Depends on the circumstances . . . need an old skool GM ruling.

You might do some sort of Save; hopefully a comrade would try to help

I would hate for a PC to die like that. It just seems cheap. But it could happen

[Dimirag]

There are lots of possibilities here, not counting swimming rules

You could make characters be able to hold their breath for a 1+Con bonus rounds, with quick preparation they can add a d6 roll to that value, with good prep roll 1d3+3 instead.
Once time has run out character starts drowning.
-You can call for a Death Saving Throw, if successful next round ask for another with a penalty, and so on, failure means death
-You can go with hit points damage, specially if you use poisons this way
--1d6 damage per round, or and incremental value (1d6, then 2d6, then 3d6 and so forth)

[Seven]

Maybe a periodic swim check can be made to see if a character can swim.
There would be a bonus for knowing how to swim/having swum in the past and negative bonus for armor, backpack, etc? Just making the check periodically would account for the swimmer getting tired.

A swimming character who suddenly goes under wouldn't have a chance to hold his breath.
A falling character who doesn't know he's heading towards water might not think of doing so.
A character in plate mail, might just try to hold his breath and hope someone fishes him out in time.

Also recovery from swimming is possible.
My last daughter drown when she was 8.
They fished her out of the community pool and called an ambulance.
When I got to the hospital I was told she had drown but that they had been able to reanimate her. We got her back once they were done pumping her stomach. None the wiser.

[Dimirag]

For swimming I would go with rules similar to climbing, 1 roll per 100 feet, water current could modify the distance while encumbrance, armor and the water flow could impose penalties to the roll.
Character that know how to swim should have higher values that other characters, my quasi-class "savage" was used with this mechanism in mind.
Now, as for sinking, you can use the final roll like rolling a set number or above (the number increases with encumbrance and armor), rolling a set above the skill (like double or skill+40 or more), or require some specific amount of failures (like 3 in a row, or 3 nonconsecutive ones).

[Seven]

The original B3 suggested something like 25% chance of drowning in leather, 70% in chainmail and 95% in plate. I feel a strength bonus is appropriate here, but only to negate the armor penalty. It seems a potion of giant strength would help to swim in plate, to a degree at least.

Thieves seems the most likely to be good swimmers.
It's a great skill to be able to get away from guards in armor.