Taylor Swift -- Boat Torched Near Beach House ... 'Property of Taylor Swift'

Taylor Swift just lost an awesome $150k boat after it was burned to the ground on a beach near her home ... at least that's what vandals want you to think.

The 35-foot cruiser washed up on shore in July and was abandoned after its owner couldn't afford to have it moved. We're told that's when some punk decided to spray paint, "Property of Taylor Swift" on the side of the rig.

However, law enforcement tells TMZ Swift had nothing to do with the paint or fire and it's now an arson investigation.

The thing is ... Taylor could have claimed the boat because in Rhode Island an abandoned vessel is fair game to anybody after 45 days.

It was a bit of a stretch considering the only thing we know of Swift burning is pictures.