Crates filled with "Pieces of Eight" are salvageable items in Endless Ocean 2. These are shown to be made of metal, wood and high-density materials when scanned using the Multisensor.
"A box filled with "pieces of eight", Spanish silver coins from the late 18th century. Definitely a pirate's treasure!"
The appraisal reward for finding one of these crates is 2,200 pelagos.