noun
hull
HULL/hʌl/
The main body of a ship, boat, or aircraft.
The wooden hull rests on supports in the workshop.

Etymology
Probably a figurative use of hull for an outer covering. A separate nautical source has also been proposed, so the relationship is not certain.
In context
The ship has been preserved in a state of suspended animation for 500 years. The images returned by the AUV are haunting. The hull is largely intact, its ribs and planking clearly visible against the mud.