My issue is that the very definition of a "clipper ship" requires three masts, square rigging, and a narrow hull. Without all three of those features present, they would not have called it a clipper. If the resemblance is close enough such that they would call it a clipper, then it clearly has sails. If it has sails, then what is the fusion core for?
Don't get me wrong, you can have all these things on the ship, but it's all in the tone and sentiment as to how your reader receives it. Admittedly, I'm a big fan of naval warfare in the age of sail and probably knows more than your average reader, but to me it reads as if you simply picked the "most advanced" ship of the age of sail and used the name without understanding what that term implies.
This is what you wrote:
Subject appears in the design of a 19th century clipper ship. Hull is constructed entirely of plastic. Fuel source indeterminate, appears to be a failed cold-fusion reactor. Several mounts for large artillery pieces are visible across the deck, but are empty.
This is what I'm suggesting as an alternative:
Instance appears to be a ship of similar design to a 19th century clipper ship, notably modified for military use instead of trade. Several gun mounts are present on the deck, but all were found empty. A device that appears to be a non-functional cold fusion reactor was found below deck, purpose unknown. Hull is composed entirely of plastic.