The curved ribs of a wood hull of a 9.75-metre 18th century boat poking up from the mud at the World Trade Center site, in New York, yesterday. Archaeologists said the vessel probably was used along with other debris to fill in land to extend lower Manhattan into the Hudson River. They called the find significant but said more study was needed to determine the age of the ship. They found a 100-pound boat anchor in the same area on Wednesday, but they are not sure if it belongs to the ship.