Here's what I have attempted, and all of which have failed:
- Going to the shore and trying to walk onto the shore
- Right-clicking on the boat, hoping to find an option such as 'Get off boat'
- Right-clicking on the shore
- Attempting to toggle swim while in the shallow water near the shore
- Logging out and logging back in to see if there is a bug that is preventing me from doing this
- Attempting to travel to my hearth fire to escape my boat-prison
- Left-clicking on the boat
- Left-clicking on the water and shallow water near the shore
There was but one solution that allowed me to escape, but required that I logout, login, and then choose to start playing from 'Your hearth fire'. This was my last resort and I don't plan on doing this because my hearth fire is dreadfully far away from my current location. Plus my hearth fire is inconveniently on a large island of which I cannot escape without the assistance of a rowboat.