Can anyone help a New Boat Owner ona custom Ketch?
I suggest you talk to the person you bought it from, tell them you made a mistake and ask them to take it back. Tell them they can keep your $100. If they agree, transfer ownership to them in whatever manner is legally effective in your state.
If that doesn''t work, my next suggestion is that you seek advice from a local attorney. You might be entitled to free assistance from a legal aid lawyer, if you are unemployed, or qualify on the basis of limited income (even if your sig. other has a much bigger income).
IMHO, some rat took advantage of you, and I believe a clever, resourceful lawyer can help you, and, if he has a daughter himself, he would take great pleasure in doing so.