This recounting of a Pacific run aboard a merchant marine ship from boating journalist Allen may be prosaic, but it is also lulling, as if it had caught the rhythm of wide ocean swells. Recently married to the first mate of the Endurance, a Titanic-size containership, Allen elects to go along with him on his next assignment. They would ship out of Oakland, Calif., en route to the Far East, with stops in the Aleutians, Japan, China, Hong Kong, Taiwan, Okinawa, and other ports of call, then make a long pull back to Long Beach, Calif. Allen's log of the trip is interspersed with annotations, histories (both personal and maritime), port tours, details of the ship's Brobdingnagian architecture, and a taste of what it is like to work for the merchant marine. She recounts the brutal hours, the quarrels and differences between crew members, the travails of women mariners. Allen depicts a world in flux (though often ruled by protocols dating back to the Hanseatic League): The arts of celestial navigation and sea savviness--skills that tempted the officers to the sea in the first place--have been replaced by global positioning systems and computer printouts. Dismayingly, too, she makes clear that the US shipping industry is taking its last bows; now down to 298 ocean vessels, it's a victim (as Allen would have it) of union bloat and flags of convenience. The book is prey to the doldrums of shipboard life, but when Allen gets a chance--recalling a brush with mean weather or the abuse a female engineer endured--she can write with powerful immediacy. Allen's voyage may not have been ""two years before the mast"" (seafarer Richard Henry Dana is a great hero of hers)--it was actually two months aft of the mast in a sixth-floor stateroom--but one leaves her book sensing she paints a genuine portrait.