Between 1850 and 1858, Donald McKay of East Boston built 31 clipper ships. Twelve were extreme clippers and nineteen were medium clippers and clipper barks. Although the lines of McKay's ships were not substantially different from other clippers built along the northeast coast from Maine to Maryland, his ships sailed with exceptional speed. In Flying Cloud (William Morrow, 304pp, $25), David W. Shaw tells the story of the record breaking maiden voyage of McKay's most famous extreme clipper.

The typical passage of a merchant ship between New York and San Francisco in the 1850s was about 200 days. The gold rush, however, created highly volatile but hugely profitable markets for just about everything that could be supplied. Overland routes, trekking across the continent or steaming to Central America and trekking through the Panamanian jungle were more time-consuming and life-threatening. They were simply not an option for shipping tons of profit-making goods. As for steam powered vessels, sail was cheaper, and clippers were faster. With no coal to carry they also held more cargo and theoretically at least, had infinite range. Steam, of course, would eventually take over but not for a while.

In 1851, Flying Cloud made her 16,000 mile maiden voyage around the Horn from New York to San Francisco in 89 days and 21 hours. She broke her own record in 1854 making the passage in 89 days, 8 hours. All of Mckay's extreme clippers performed in the same league.

The story of the Flying Cloud is exciting in itself, but author, Shaw, has added an unusual twist by focusing on Eleanor Creesy, the navigator of the great ship. Remarkable for being a functioning female member of the clipper's crew, she was also an inspired navigator. Her skills are considered to be a major contributing factor in the ship's safe and swift passages. A native of Marblehead, Massachusetts, Eleanor Creesy learned navigation from her father, a successful captain in the coastal schooner trade. When she married Josiah Perkins Creesy in 1841 he was master of the Oneida plying the China trade and wishing for a faster vessel. She sailed with him throughout his long career.

Shaw's account is very well researched, especially on the subject of rigging and sailing. What becomes immediately apparent, is that in addition to savvy navigation, the clipper's speed was caused by the piling on of sail. The stress of full sails on Flying Cloud's spars caused cracks and splits and snaps even before the ships crossed the equator. Extra sticks were carried in anticipation of such breakage but the ship's carpenter was constantly busy jury-rigging, the crew frequently aloft (125 feet above the deck) installing new spars. Although Shaw has not provided his subjects with much personality it is clear that Josiah often drove his ship beyond the breaking point.

The book is generously illustrated with photos, lithographs and woodcuts of the period as well as charts, diagrams and maps. In the text, however, more information is provided than necessary. No doubt because Shaw is such a thorough researcher the book could use a crisp editing but although his narrative non-fiction style is heavy the subject carries the day.