Swimming

A character with a dot of Athletics is assumed to be able to swim. A character without a dot of Athletics is assumed to not be able to swim. Swimming in normal conditions generally requires no roll. If speed is important or conditions are unusually difficult, a roll should be made. Long distance swimming requires a Stamina + Athletics roll difficulty 5 for an hour assuming the character is opting for a slow steady pace.
The second hour raises the difficulty 6 and so forth and so on. Swimming at a fast pace will naturally tire out characters much quicker.
If the character is fighting a current or riptides, they should roll Stamina + Athletics to move every 10 yards. Failure doesn’t cause the character to begin to drown but the character may lose ground.
Characters generally only risk drowning if they botch a roll barring some hostile force holding the character’s head underwater.
Creatures with an aquatic movement rate can automatically cover distances at their base rate under normal circumstances, without rolling at all. If the water is treacherous, aquatic creatures get a -2 difficulty on their swimming rolls relative to what a normal land-based humanoid would have to deal with.