If you aren't willing to accept that this sort of thing might happen, Early access probably is something you should avoid in the future. Even just whether saves will be compatible before and after an update (i.e you have to start completely over) is something that can, and does, happen in Early access titles. 2 hours of lost time is nothing in comparison to that.

That said, the "save" command now makes sure to do a character save as well as a world save as of the most recent patch, so you might want to make a mental note to do that before setting out to see with a full load, just to be safe.

Your boat is probably still out there, btw, waiting for you to find it. I use a mod that puts map markers on boats and carts specifically as an 'in case' something like this happens.