Thanks for all the comments.
- Running windowed should already be possible, through the unity resolution menu. Holding shift when you start the game should give this.
- You don't automatically get saving and loading in Unity. I'm not sure it's worth it for a sandbox like this.
- Good point about reefing topgallants. There's a general UI issue about reefing and storms, namely, how can the player tell whether they have too much sail. You could put a strain gauge somewhere, or have it done automatically or get suggestions from your lieutenants; or keep things immediate and unsubtle.
- Sails aren't textured at all at the moment.
- "Miles travelled" - would be a good thing to put on the map when I redo it.
- Wind rising or falling - For one thing, there should be a more intuitive display of the wind level, at least something graphical with the pointer on the compass. For another, the wind changing is only an issue when using time acceleration, and time acceleration in general should be made less unfriendly to the player and, e.g., make or take in sail automatically, as though the watch-officer was doing it.
- I'm glad someone made it across the Atlantic. Right now there is no collision testing done between the camera and terrain - it sounds like you have the camera inside the terrain.