Originally posted by Enorats:

There is a mod that makes it so the wind always changes to be at your back when your sails are deployed.

The game seems to be intentionally made so that the wind shifts to be directly against you every few moments. It's incredibly frustrating, and quite noticeable. I spent a LOT of hours playing games like Naval Action and other sailing games.. and this one really sticks out in terms of the frustration of dealing with the wind. Here, you pretty much just don't.. because it just shifts to be against you again.

As far as I know, the wind starts at a given direction and speed, and varies in pseudorandom directions and strengths at pseudorandom intervals. There appears to be nothing more sophisticated than "roll new direction, roll new speed, roll duration until next set of rolls." The fact that about 75% of the possible directions for the wind to be blowing are not aligned with the direction you want to go at any given time, statistically speaking, couples with common human cognitive failings to leave many people with the impression that it's somehow unfairly working deliberately against them.

On the bright side, as far as I know, you can make close to if not true full speed in a longboat provided a wind direction from anywhere within the aft 180 degree arc relative to heading, so about half the time, you should be just fine. Anytime you really have to get somewhere with the wind directly in your face, you can always beat if you want to (good for filling in map and discovering new lands and bumping into serpents), or furl the sail and row if it's that important. But really, even just hugging a quartering headwind under sail power will still give you decent speed.