A china bowl protruding from the muck inside the Captain's cabin of an unidentified Japanese 110-foot long whaler-configuration small freighter sunk upright in 130 feet of water off the south end of Ebwaj Island. Muck is a fine, oozy sediment within wrecks formed by the decomposition of anything organic. It is readily stirred up and can easily obscure a diver's vision. Divers have lost their orientation, and their lives, by digging in the muck--mucking--for artifacts. Mucking inside a wreck is something that should be undertaken only with great care and forethought.