From the article.

"Although he was able to move the home in this manner, Lozman said it should not be covered by maritime law because it lacked the usual seafaring features such as a motor and GPS device, and needed land-based sewer lines and an extension cord for power."

Sooo, in order to be covered under maritime law a vessel must have a GPS and motor? Hmmm? And since it was plugged into shore power it wasn't considered a vessel?

I guess I have no idea what a vessel is.