In the spring of 1991 a number of interesting cruises along America’s East Coast were last-minute inspirations, dictated by the Persian Gulf War. Instead of plying their usual Mediterranean routes, such lines as Cunard and Royal Viking sent ships to Charleston and Savannah, Baltimore and Boston. Some of these trips will be repeated in 1992, now that the lines have had a chance to gauge their popularity. Passengers were surely aware that a war in the Mideast had prompted their ship’s American itinerary, but most of them probably didn’t know that the exact and sometimes odd configuration of their cruise was dictated by a 1920s law of Congress informally known as the Jones Act, which was designed to protect American merchantmen.

When the Royal Viking Sun started a May cruise in Montreal, followed the coast south and inland as far as Baltimore, then veered east to Britain’s Atlantic outpost of Bermuda for a day before heading for more U.S. ports, the motive wasn’t just an agreeable look at some fascinating places. No, the ship was following a law that says vessels not built in the United States and not registered here (probably 99 percent of cruise ships) must intersperse foreignport stops among their American ones.

Designed for a time when countless merchant and cruise ships flew the American flag, the Jones Act is probably worth another look these days. One line that needn’t give it another thought, however, is Clipper Cruise, whose two small and elegant ships were built and registered in the United States and whose crews are entirely American. Their slender, shallow-draft vessels, the Nantucket Clipper and the Yorktown Clipper , are free to venture into smaller harbors and narrower waterways than the behemoths could navigate even if favored by law.

Last April I traveled north from Jacksonville to Charleston on the Nantucket Clipper , using the Atlantic Intracoastal Waterway. This is the watery Route 1 of American travel, extending from the Annisquam Canal twenty-three miles north of Boston to the Florida Keys. Because some of the Northern sections are now closed, mile O at Norfolk, Virginia, marks the official start of the waterway, which is navigable south of there only for small craft. In dictionaries and encyclopedias it might be listed under “Inter” as well as “Intra,” and it’s sometimes referred to as the Inland Waterway. The waterway’s history can seem as ad hoc as its various names. It was in use well before Europeans appeared, as the way Native Americans got around. In 1643 some Massachusetts colonists dug a half-mile canal linking the Annisquam River and Gloucester Harbor to create what is considered the route’s earliest “improvement.” When George Washington had a portion of the Dismal Swamp surveyed in 1763, he was helping extend the waterway. Exactly thirty years later work finally began on the Dismal Swamp Canal, connecting rivers in Virginia and North Carolina. It was a private venture; not until 1828, with the enlarging of the channel between Georgia’s Cumberland Sound and the St. Johns River in Florida, did the federal government become involved.

After the final portion had been completed in 1936, between Little River and Winyah Bay in South Carolina, the Federal Writers Project celebrated with a book, which remains the only historical look at the waterway from end to end. ”… here were enacted many of the most important early scenes in one of the most amazing adventures of all time, that of the expropriation of a continent,” the anonymous author writes, with what might appear to us today as unseemly glee. “These are the lands first sighted by many of those hardy scouts of empire of the sixteenth and seventeenth centuries whose knowledge of the earth was so sketchy that they imagined they were here seeing the shores of India or China.”

The people who run Clipper are well aware of the lure of that history, and they allow time to sample it in a number of ways. There is the simple pleasure of waking, after a nighttime departure from Jacksonville, to the waters at the marshy fringe of St. Simons Island in Georgia. The naturalist on board, Charlie Rouse, already dubbed by passengers “the bird guy,” has discovered two boat-tailed grackles engaging in a courtship display, and he insists that a speck in a tree is a crested flycatcher. Later, on a morning walk through the village at St. Simons, Rouse listens to a rather raucous birdsong and identifies it as that of the Carolina wren: “It goes teakettle, teakettle, teakettle .” The botanist William Bartram came this way in 1776 and wrote of Georgia’s “marvellous scenes of primitive nature, as yet unmodified by the hand of man.”

There is time also at St. Simons to stroll on a generous swath of public beach and to join a bus tour to learn more about the hand of man on the island, from its early days as a prize of empire sought by the Spanish, British, and French to the full flowering of its plantation culture, wrapped around the products of indigo and sea-island cotton. The tour also reveals St. Simons’s later incarnation as a resort, with a drive past the Addison Mizner-designed Cloister Hotel and its immaculate, oak-alleyed grounds. The enormous, outreaching live oak, with its generous gray-green fringe of Spanish moss, remains as much the emblem of the Georgia landscape as it was when seen by a traveler in 1745: “… the lofty Oak, with all his kindred tribe clad in Robes of antique Moss seems by its venerable Appearance, to be the real Monarch of the Woods …”