"VOYAGE OF THE St. Louis" is not a comfortable exhibition in any sense of the word. Like most everything else at the U.S. Holocaust Memorial Museum, this story -- about a ship of 936 European Jews fleeing Nazi Germany in 1939 and its failed journey to find safe harbor in America -- makes you work hard, and leaves you feeling sick at heart.

The effort and pain are well-rewarded.

From the very first wall panels, viewers are asked to kneel and squint at the faded photographs and text on yellowing scraps of paper hung low in the museum's deliberately dim lighting. On one level these conditions exist to preserve the fragile items, while on another they serve as ascetic mood-enhancements designed to foster the museum's appropriately sober atmosphere (in what other museum will visitors routinely shush someone for speaking too loud?).

Even more, the drama of dashed hopes and national shame that plays out on these few walls is itself an uneasy one, for in a half-dozen glass cases we can see reflected a bony finger of blame pointed squarely back at us.

Sixty years ago this month, the SS St. Louis set sail from Hamburg for Havana. The vast majority on board were Jews in flight from Nazi persecution who had bought landing permits for a couple of hundred dollars from Cuba's corrupt director of immigration. Many had already been briefly incarcerated in Nazi camps and had been released -- sometimes through bribery -- on condition that they emigrate immediately.

Unbeknown to the travelers, however, Cuban President Federico Laredo Bru had invalidated the fraudulent permits and, upon the St. Louis's arrival in Havana harbor, did not allow anyone to disembark. For one tense week, the ship and its increasingly panicked passengers languished in the water, while a representative from the American Jewish Joint Distribution Committee negotiated unsuccessfully for a resolution with Bru. Suicide prevention boats bobbed alongside the moored ocean liner after at least one desperate passenger slashed his wrists and threw himself overboard.

Leaving Cuba in early June, the ship then headed for Miami where, again floating in limbo just off the Florida coast, the refugees hoped to persuade the U.S. government to let them in, despite already overflowing immigrant quotas and waiting lists thousands of names long.

Long story short: The United States said no. As bluntly put in a terse letter of refusal, "The German refugees . . . must await their turns on the waiting list."

Upon its return to Europe in mid-June, St. Louis passengers were able to find refuge in Great Britain, France, Belgium and the Netherlands. Within a matter of months, though, most of the exiles (with the exception of those passengers admitted to England) once again found themselves in jeopardy as the cancer of Nazi occupation spread through Europe.

Some eventually escaped to safety; others went into hiding; hundreds more were to perish in death camps, after only a tantalizing taste of freedom.

"Voyage of the St. Louis" is their saga, but the show is also the account of an unusual research project: the museum's two-year effort to track down every man, woman and child on that boat and discover his or her fate. It is a memorial, the product of painstaking international detective work that today has narrowed the list of those unaccounted for to a mere 21 names. Some 30 of the last passengers' fates have been identified just since the exhibition opened in April.

Unlike much of the Holocaust Memorial Museum permanent collection, there are no computer screens here, no video or audio testimonies from survivors that allow for the passive absorption of knowledge. The tale is told silently, and the audience must lean in to hear it.

Yet despite the sweat equity it demands of museumgoers, the small exhibit has all the dynamics of a piece of tragic theater: the achingly hopeful faces seen in shipboard snapshots of happy, smiling vacationers playing shuffleboard and posing as though on a pleasure cruise; the dingy relics (a dog-eared postcard and souvenir doll dressed in the uniform of a St. Louis crew member); the nail-biting suspense of newspaper accounts (a front-page Miami Herald photo essay dated Saturday, June 3, 1939, printed the ironic caption, "Never Say Die"); and the gut-churning letters that lay out disappointment after crushing disappointment.

Of particular impact are two letters written by survivors Oskar Blechner (who was one of the lucky ones to make it to England) and Rudi Dingfelder (who, even though he was sent to Auschwitz, survived).

From the safety of England, Blechner writes -- in increasingly exclamation-punctuated prose -- a dispatch to a member of Great Britain's Jewish Refugee Committee, in which he laments his own sense of impotence and the loss of his relatives' lives while $500 of his own voucher money is tied up in red tape.

And in two touching pages of broken English understatement, Dingfelder writes to long-lost relatives after the war: "These Auschwitz is one of the frightfullest concentration camps which I have seen in my life." When he modestly apologizes: "I don't want to bore to tell you about me."

Rest easy, Rudi. Like your own story, "Voyage of the St. Louis" speaks with a quiet and halting eloquence, and the harrowing testimony it has preserved is anything but boring.

VOYAGE OF THE ST. LOUIS -- Through Sept. 6 at the U.S. Holocaust Memorial Museum, 100 Raoul Wallenberg Place (15th Street) SW (Metro: Smithsonian). 202/488-0400. Open 10 to 5:30 daily, Thursdays until 8. No tickets are required for the "St. Louis" exhibition; admission to the permanent Holocaust exhibit is by free, timed-entry tickets available at the museum or through ProTix (800/400-9373; service charge added). Web site: www.ushmm.org.

Free public programs associated with the exhibit include:

June 3 at 7 -- An evening with Henry Blumenstein, Ruth Loeb Forest and Ilse Marcus, three survivors of the St. Louis.

June 10 at 7 -- World War II relief worker and scholar Amy Zahl Gottleib discusses the 287 St. Louis passengers who found refuge in England.

July 15 at 7 -- Documentary film: "The Voyage of the St. Louis," with an appearance by film producer Arnie Gelbert.

To reserve seating for these events, call ProTix at 800/400-9373.

CAPTION: Jewish refugees look through a porthole while docked in the port of Havana.

CAPTION: Oskar Blechner, a passenger who eventually found refuge in England, holds onto the SS St. Louis's life preserver.