The environment settings for rivers could benefit by including "downstream" as an option for direction of current. As matters now stand, one can only select a compass direction, and this makes rivers quite unrealistic. For example, navigating down the Rhine one proceeds in a generally NNW direction, but with so many river bends setting the current to, say a fixed 320º, the program generates a very implausible right-angle current depending on vessel heading. Simulating true downstream flow, with the occasional eddies, bank effects, etc would more closely replicate the real-world experience.