ASTORIA -- Hidden beneath the ever-changing waters at the mouth of the

and its world-famous bar, the

spit and the Graveyard of the Pacific is a pioneer vessel that played a significant role in the greatest period of Chinese emigration in U.S. and Chinese history.

The S.S. Great Republic, one of the four original Pacific Mail Steamships that were the world's largest passenger vessels of their day, brought ashore thousands of Chinese who shaped the heritage of Oregon and the U.S.

The pioneers from the Pearl River delta and Guangzhou (Canton) in Guangdong Province seeking Gum Shan -- their Mountain of Gold -- could not have established Portland's Chinatown, mined the state's silver and gold, helped build its railroads or tilled the rich soil of the Willamette and Hood River valleys without these ships.

The

's final resting place was last observed in 2004 just off Sand Island on the Washington side of the Columbia Bar, across the river from Oregon's Maritime Museum in Astoria. It is the sole wreck site in the U.S. that represents the origins of Chinese immigration before the 1882 exclusion laws.

Two months before his assassination in 1865, President Abraham Lincoln signed legislation authorizing construction of the four largest passenger sidewheel steamers in the world in New York, and a subsidy for the Pacific Mail Steamship Co. to operate them.

The lead ship was named the Great Republic, underscoring a renewed hope after four years of civil war. She was the toast of America, gracing the front page of the Nov. 26, 1866, edition of Harper's Weekly.

The New York Times and New York World reported that the 4,000-ton ship -- 380 feet long, 50 feet wide and 31 feet deep in the hold -- was the largest commercial vessel ever built in a U.S. shipyard.

The Great Republic's keel was laid in January 1866. During a tight 10-month schedule, workers built the large coal bunkers, four boilers and the ship's signature vertical "walking beam" engine connected to two paddlewheels that were 40 feet in diameter and had 34 oak buckets that were 24 inches wide.

They would propel the ship at 9 miles an hour for 33 days at a time across the Pacific. The Great Republic could carry 250 first-class passengers in ornate berths and 1,250 third-class passengers in sparsely lit berths, plus its team of professional U.S. and Chinese Pacific Mail crews.

Her sea trials were completed in the spring of 1867, and a 77-day shakedown voyage from New York took her to new home port of San Francisco. On Sept. 3, 1867, the Great Republic began her working life with regularly scheduled service to Japan and China to deliver mail, transport U.S. and Chinese passengers and conduct trade in textiles, Oregon and California wheat and labor.

The Great Republic completed 25 voyages during her transpacific service from 1867 to 1877, transporting more than 10,000 Chinese to San Francisco, about 10 percent of Chinese emigration to the U.S.

These Chinese, known as

, emigrated under the Burlingame Treaty between President Andrew Johnson's administration and the Qing Dynasty, which established friendly relations between the nations, and the new 14th Amendment.

Almost all began their journey as laborers from districts of Guangdong or as merchants and craftsmen from districts around Guangzhou. They made their way from San Francisco via Astoria, Portland and The Dalles to far-flung parts of the Northwest, establishing Chinatowns, mining activities, ranches and merchant life in places such as John Day.

In 1878, the twin forces of new technology (propellers) and opportunity (potential profit) led to the sale of the Great Republic to P.B. Cornwall. He used the ship to offer a comfortable San Francisco to Portland passage with lower freight rates and higher passenger loads.

In her new role, the Great Republic sailed from San Francisco on April 16, 1879, with 550 cabin passengers and 346 steerage passengers.

It was to be her final voyage.

She arrived off the Columbia River mouth at midnight and embarked a bar pilot. After assessing the calm, favorable tidal conditions under a clear, starlit night, the crew took the ship across the bar over the next hour.

Suddenly, there was confusion in the pilothouse. Captain James Carroll thought the ship was too close to Sand Island. Bar Pilot Thomas Doig thought that she had not yet gone far enough into the river.

An urgent order to turn to port and safety could not overcome a strong ebb current that put the Great Republic hard aground at high tide on Sand Island.

The plan was to wait for another high tide and pull the ship off the sand spit with four local tugs. But the next tides were not high enough, and Carroll decided to send the passengers on to Astoria aboard the tugs.

Upon arriving in Astoria, the passengers published a card in the papers thanking the captain, crew and tug operators for their efforts to save their lives.

The crew wasn't so fortunate. They had waited until the last possible moment, and the last boat was caught in a heavy sea, capsizing it. Eleven crewmen drowned, including the first officer. Seven of the 27 horses on board reached Sand Island.

An urgent salvage operation over the next week couldn't free the ship before it was broken into three large pieces by the ferocious sea and tides. One hundred feet of bow broke off and was beached. The hull aft of the engine broke away and disappeared.

For years after, the engine and sidewheels remained in view of gunners at Fort Canby on the north bank, and at extreme low tide, portions of the wreck still are visible on Republic Spit. These include the ornate saloons where first-class passengers and U.S. naval officers in the Asiatic Fleet spent their time aboard.

The submerged parts, however, weren't rediscovered until 1986 and again in 2004.

The Great Republic's treasure tank, which secured millions of dollars in silver and gold from the Comstock Mines and San Francisco or Carson City mints, lies somewhere on the bottom. The propulsion system is still connected to its wooden frame and is waiting to be uncovered.

The decks below, where thousands of Chinese endured their voyage, were driven into the sand by tidal forces and may survive to be rediscovered. This is where the Sojourners slept in their regional attire, listened to Chinese guitar, stood in line three times a day for their rations of rice, and -- for some making a return trip -- adjusted the money belts containing $20 gold pieces and gold dust representing their hard-won earnings from their Gold Mountain labors.

Within sight of Astoria and Ilwaco lies not just a shipwreck, but a historic shrine of America's Chinese ancestors.

-- Robert Wells, special to The Oregonian

Robert Wells is a retired U.S. Navy captain and Operation Enduring Freedom veteran. He commanded two U.S. Navy ships on visits to Astoria and the Portland Rose Festival. Contact him at robert.s.wells@hotmail.com