They were human skeletons wearing tattered uniforms. The captain wore blue; the rest wore dark orange. The captain also had a gray mustache and beard.
The Dauntless was a cargo ship carrying priceless treasure near Lake Michigan, Wisconsin. While making the trip, it managed to get caught in a terrible storm. Deciding to take advantage of the situation, the lighthouse keeper switched off the lighthouse with the intent to cause the Dauntless to crash into the rocks and steal the treasure. Supposedly, the crew were never discovered. The Dauntless would not be discovered either, since the lighthouse keeper was knocked from the top of the lighthouse and died.
What's New, Scooby-Doo?
Fred Jones, Daphne Blake, and Velma Dinkley found the skeletons when they went to search for the ghost of the Dauntless. The ghost ship rammed and destroyed their motorboat, forcing them to board it. They hid to avoid being noticed by the skeleton crew, who drove off on a motorboat.
The culprit behind the skeletons was revealed to be Crusty McPeet. He discovered the resting place of the sunken Dauntless, so he fabricated the ghost ship and built the skeletons to scare people away while he searched for the treasure. His scheme was uncovered by Verona Dempsey, who caught him in a net.