A year is not that long to be alone. Sure for some it would be and you wouldn't know if you like it until you tried it. I know I can so see no challange other than the money part. On a boat you will not be able to avoid people unless you bob about in the ocean in which case weather will likely end the experiment.
If you are wondering if you can handle isolation a boat is not needed.
You can even talk to people and be alone. Move away, do not make any friends, keep all conversations to a minumum, and see how you do. How long before you start to need those connections, how long before you have to reach for the internet, TV, or other media to feel connected. You can even find a job that has little interaction. Some people love it, others not so much.
Have faith that the oceans are going to rise and flood the world, that plague and pestilence brought on by Climate Change is going to punish us for not believing. Please do as they say it is our only hope. :P