In 13 voyages, the three-masted barque Jeanie Johnston carried 2,500 desperate passengers fleeing the Irish potato famine for North America, destinies unknown.

In today's happier Ireland, where incomes are rising, jobs are plentiful and tables groan with food, the wooden-hulled Jeanie Johnston is getting ready to sail yet again--a replica of the original vessel, that is. She is being lovingly constructed by volunteers from Ireland, Northern Ireland and the world, who are preparing her for a celebratory voyage to the United States and Canada in April.

Most ships of the mid-1800s were overcrowded, disease-ridden vessels called "coffin ships" because of high loss of life among passengers. But the Johnston was one of the few Irish immigrant ships on which not a single passenger died, and one aim of the coming voyage is "to show a positive side of history--people did make it across," said Robert O'Sullivan, a guide at the Jeanie Johnston project on Ireland's southwestern coast.

For Harry Cross, 42, a volunteer carpenter who hails from South Philadelphia, the chance to help replicate a 19th-century wooden sailing vessel is simply "awesome." "She's not just a piece of wood," said Cross, whose mother's great-great-grandfather Jeff Heffron left an impoverished Ireland for America in the 1800s. "I guess it's a tie to my heritage. You can see the way [people] lived. They really had it hard."

The hard life of rural 19th-century Ireland got infinitely harder in 1845 when a rampant fungal blight called phytophthora infestans began rotting potato plants. The impact was devastating. More than 4 million Irish, from landless laborers to small landholders, depended on the potato for food and employment. Many families had routinely survived on nothing but dozens of pounds of potatoes per day, abetted by buttermilk, cabbage and occasional fish.

As the famine's effects rippled through the countryside, Ireland's population dropped by 2 million, from 8.5 to 6.5 million, between 1845 and 1851. A million died--some from starvation, but most from typhus, yellow fever, dysentery and other diseases that ravaged a hunger-weakened population. Roughly 1 million fled their homeland on ships like the Jeanie Johnston, many enduring six weeks of waterborne hell on the transatlantic passage.

More than 200 passengers could be crammed into the hold of a typical small ship. Water turned foul, flour became infested, chamber pots overflowed. Death rates on the ships ranged from 3 to 20 percent. "Once a fever got going on a ship, there was nothing you could do," said project historian Helen O'Carroll.

The Jeanie Johnston was different, though. Built in Quebec in 1847, she was sold to Irish businessman John Donovan and his son Nicholas the following year. It is not clear whether Nicholas Donovan operated the Jeanie Johnston properly because it made good business sense or out of altruism, but that is what he did.

Although regulations at the time required passenger ships to have a physician aboard, most shipping companies skirted the rule. Not so Donovan. He supplied the Johnston with a full-time doctor, Richard Blennerhassett, from the family for whom this coastal town is named.

Between voyages, the ship was thoroughly cleaned. Not only did no one die while aboard her, but she spawned life: A baby boy was born onboard one day before the ship's maiden passenger voyage in April 1848.

The original Jeanie Johnston lies somewhere beneath the mid-Atlantic, where she went down in October 1958. By then strictly a cargo ship, she slowly sank when a shipment of lumber became waterlogged. Again, the good ship Johnston saved all aboard; her crew members clung to a tall mast until the could be rescued by a passing Dutch vessel.

In the mid-1990s, business leaders here began raising money for construction of the ship's 150-foot replica, meticulously crafted from Irish oak and Austrian larch. The nearly $9 million project received its largest donation, $600,000, from the Dublin-based Elan pharmaceutical company.

Although several professional shipwrights are working on the replica, most are volunteers who are paid about $150 a week and receive free room and board. Cross, a journeyman from Philadelphia's Local 1050 of the Brotherhood of Carpenters and Joiners, is one of a half-dozen Philadelphians working on the project. Most learned about the ship through membership in the Ancient Order of Hibernians, a fraternal organization celebrating the Irish heritage.

One of the Philadelphia volunteers, 24-year-old Danny Market, plans to marry fiancee Helen Monaghan aboard the ship when the vessel docks in the United States. The Jeanie Johnston is expected to tie up in Philadelphia for eight days beginning June 1. During an eight-month tour, she will put in at a number of cities along the East Coast of the United States and Canada and on Lake Michigan.

Because passenger records were lost or destroyed, little is known about the fates of the original passengers who took her to North America between 1848 and 1854. To the amazement of historian O'Carroll, the descendant of one of the original passengers showed up at the ship's visitor center last summer. He was John Kudlik, a teacher of medieval European history at Allegheny County Community College in Pittsburgh.

Kudlik said his great-great-great-grandfather Daniel Dowd left Ireland on the Jeanie Johnston in 1849 and quickly built a dairy business in the Washington area.

"I did a little sailing on a 78-foot ketch in the Caribbean," Kudlik recalled in a phone interview from Pittsburgh this week. "It was hard to fathom a boat not too much bigger than that crossing the Atlantic with that many people on it. I guess I'm sitting here because they did take such good care of their passengers."

CAPTION: Volunteer workman Aidan Frawly, of Toronto, left, helps Irish shipwright Tony Gay and another volunteer bolt planks to the keel of the new Jeanie Johnson.