the York River could be clarified by industrial filters, an idea Norman Scott had earlier suggested for other sites with zero visibility.

Elsewhere in the United States, the famed “cheesebox on a raft,” the Civil War ironclad Monitor, the first gunboat with a revolving turret, was located in 1973 seventy meters deep about seventeen miles off Cape Hatteras, North Carolina, by a Duke University team using sonar. Two years later, the archaeologists Gordon Watts, John Broadwater, and others visited the Monitor in the Harbor Branch Foundation’s Johnson-Sea-Link I, a submersible from which they could be launched into open water to swim around and examine the site.

The 1968–1969 dryland excavation of the steamboat Bertrand, sunk in 1865 twenty-five miles north of Omaha, Nebraska, in the Missouri River (which had since changed course), was supervised by U.S. National Park Service archaeologists. The project yielded not only a well-preserved hull but nearly 2 million artifacts, including bottles with their paper labels intact.

In Canada, the amateur archaeologist Daniel A. Nelson, after searching with side-scanning sonar in an area narrowed by archival research to thirty-two square miles, in 1973 located two warships sunk during the War of 1812, the Hamilton and the Scourge, ninety meters deep in Lake Champlain. Inspected and recorded from a research submarine and by a remotely operated vehicle (ROV), the ships proved to be almost perfectly preserved with upright masts, figureheads in place, and skeletons of the crew on the decks.

Pioneering work on ships in the Far East was conducted both on land and under water in the 1970s. At the port city of Quanzhou, china, a thirty-four-meter ship of the thirteenth century a.d. was discovered and excavated in 1973, and a fourteenth-century wreck with an immense collection of Chinese ceramics was excavated by the Korean navy after the ship was discovered near Shinan, Korea, by a fisherman in 1975. Both ships offered the surprise of V-shaped hulls from a time when scholars assumed that all Chinese ships were flat-bottomed.

In Mombasa, Kenya, Robin Piercy of INA began, in 1977, the first full-scale shipwreck excavation in East Africa on the remains of the Santo Antonio de Tanna, a Portuguese ship built at Goa and sunk in 1696 while trying to help relieve a siege of the Portuguese fort, Fort Jesus, by Omani Arabs. During the same period, Colin Martin continued excavating two Spanish ships—El Gran Grifón and La Trinidad Valencera—that had fled north around Scotland and Ireland following the defeat of the Spanish Armada in 1588.

1980s

A number of projects in the 1980s proved that wrecks could be found and at least partly recovered from any depth and at any temperature. In the first year of the decade, using sonar, a team led by Joe MacInnis discovered the well-preserved Breadalbane under two meters of surface ice at a depth of a hundred meters in Canada’s Northwest Passage. The British bark had been sunk by ice in 1853 while on a rescue mission for the ill-fated Franklin expedition of 1846. MacInnis’s team was able to explore the site in a one-person submersible, the WASP, lowered through a hole in the ice.

In 1985, a French-American team, searching an area of the North Atlantic 350 miles southeast of Newfoundland and 150 miles square, was able to locate and examine, at a depth of 4,000 meters, the “unsinkable” Titanic, a ship sunk by an iceberg on its maiden voyage in 1912 with a loss of 1,522 lives. Preliminary images of the wreck were seen via television from ROV, and in 1986, Robert Ballard of the Woods Hole Oceanographic Institute visually inspected the site from the submarine Alvin. After the discovery, amid some controversy, artifacts were raised from the ship by a French group for display.

Equally impressive was the discovery in 1987 of the SS Central American, lost 200 miles off Charleston, South Carolina, in 1857 in water a mile and a half deep. The Columbus-America Discovery Group, admittedly after the gold bullion the ship was known to be carrying, surveyed 1,400 square miles of ocean floor with sonar to locate the vessel and then retrieved much of the cargo and other artifacts with advanced robots. In the muddy York River, John Broadwater of the Virginia Department of Conservation and Historic Resources showed that