It would be great to be able to learn how to swim, and have a skill system where that affects how much weight you can be carrying while swimming (as well as speed). There should also be currents - so you’re swept downstream.
Swimming was unpopular in the middle ages because it wasn’t socially acceptable to take your clothes off and it was pretty damned cold anyway. But soldiers were trained to swim in full armor as this gave you a tactical advantage in warfare.
It should be something you can learn - and would be useful since so many towns have rivers which could be crossed away from bridges, either to escape or sneak into town.
