It's pretty time consuming to travel around the world from one point to another. I think the base speed of knarrs in the ocean should generally be higher, and if animals need to have their speed in water raised to compensate, then so be it. The knarrs are large ships with sails, it makes sense that they'd go faster in the ocean. Could be argued that a knarrs sails should be lowered in rivers and it should travel at rowboat speed, or that wind should have direction. But thats getting a bit more complicated than it needs to be. I've finally finished nomad, but at times I would boat for well over an hour in a straight line across the ocean. Thats absurd, and I won't say more about it.
Time is valuable, please give us some back.