12-scale worms are usually found while separating and cleaning mussels. They seem to be harmless and inoffensive. In the illustration, the head is at the left. There are many varieties, some with more or less scales.
Of course, finding a shipwreck is a necessary prerequisite for finding artifacts. Many wreck locations are well known. Others are secrets, and many wrecks have yet to be discovered. While you can recover artifacts from almost any shipwreck, it is these "virgin" wrecks that are often the best producers of prize items like portholes, deadeyes, and china. But how do you find a wreck like this? Research is the most productive method. This will require visiting local libraries, historical societies, nautical museums, and many other institutions. It means lots of reading and digging for information. Be prepared to spend some time searching for clues that aren't willing to be found.