Atlantic was a wooden-hulled, side-wheel steamship launched in 1849. She was conceived as a part of an American fleet which would break the monopoly that European steamers, notably the Cunard Line, had on trans-Atlantic trade. She was the most successful of the Collins Line ships, and one of the most luxurious vessels of her day, but the company went bankrupt in 1858.

She was chartered by the Quartermaster Corps of the United States Army for much of the American Civil War. She supported the army's logistical requirements during major assaults, ran routine supply missions, and evacuated casualties, among other missions.

After the war, Atlantic was primarily used to bring German immigrants to the United States.

Over the course of her career, Atlantic completed sixty-six trans-Atlantic roundtrips, more than any other American side-wheel steamship.

Construction and characteristics In 1846, Edward K. Collins made a proposal to the United States Post Office. In return for a $385,000 annual subsidy, Collins would build a fleet of five ships that would sail between New York and Liverpool, carrying the mail, twice a month in the eight months of the year when the stormy North Atlantic was reasonably calm. He won the contract and established the New York and Liverpool United States Mail Steamship Company, which was universally shortened in common parlance to the Collins Line. Stewart Brown, and James Brown, representing the private banking firm Brown Brothers, were partners and financial backers of the company. United States Navy personnel supervised the design and construction of the Collins fleet, including Atlantic, so as to enable its vessels to be readily converted to warships, should the need arise.

Atlantic and Pacific were the first of the Collins Line ships which were built. Atlantic was built in the shipyard of William H. Brown at the foot of 12th street on the East River. The foreman on the job was George Steers. The hull was made of wood, reinforced with diagonal iron strapping. In consideration of her prospective service in the North Atlantic, she was built stoutly. The iron straps, 5" wide, and 1" thick, weighed 50 tons alone. A significant innovation in her design was her straight stem and lack of a bowsprit. This marked the ship as evolving toward greater reliance on steam rather than sail power. Both Atlantic and Pacific were launched on February 1, 1849. Atlantic's boilers, engines, and other machinery were added once the ship was afloat, so she was not ready for sea until the following year.

Atlantic was long with a beam of , and a depth of hold of . She displaced 2,668 tons. As originally constructed, she had three decks, the spar deck, the main deck, and the lower deck. The spar deck had cabins for the ship's officers, the galley, barber shop, and a smoking room. The smoking room could be accessed from the main deck by an internal staircase so that passengers would not have to expose themselves to the weather. The main deck included the great saloon, long, and the dining saloon, long. Both rooms were wide. The two rooms were separated by the steward's pantry where dishes, silverware, and other table ware were stored. The two saloons were paneled in rosewood, satinwood, and olive wood, and were carpeted. Meals were lowered from the galley on the spar deck to the dining saloon in dumbwaiters. The dining tables had marble tops. The walls were decorated with emblems of each state of the Union, and the cabin windows were painted glass with the coats of arms of major cities in the United States. A separate ladies drawing room was also on the main deck. The passenger cabins were on the main deck, outboard of the saloons on both sides of the ship. There was no provision for steerage passengers on Atlantic. She carried a crew of 170.

Atlantic had four coal-fired boilers to provide steam for her engines. She had two side-lever steam engines manufactured by the Novelty Iron Works of New York. The engines were large, each with a single cylinder with a bore of and a stroke of . The bed plate alone for one of these engines weighed 34 tons. The boilers consumed enormous quantities of coal, about 85 tons each day. These engines generated power variously reported as between 500 and 1000 horsepower each. Each engine drove a paddlewheel that was in diameter, each with 36 paddles. The ship was able to average 12 knots on a trans-Atlantic voyage. As originally constructed, Atlantic had three masts and was rigged as a bark. In 1853 or 1854 the mizzen mast was removed increasing her dependence on her steam engines for propulsion.

The first four Collins Line ships cost just under $3 million to build, suggesting that Atlantic's original cost was approximately $750,000.

New York and Liverpool United States Mail Steamship Company (18501858) Atlantic departed New York for Liverpool on her maiden voyage on April 27, 1850. She reached port on May 10, but not without teething troubles. Just over half way across, the ship was stopped to repair the loss of paddles in heavy seas. She drifted for 12 hours while repairs were effected. Then one of the engines had to be shut down due to a valve failure, cutting the ship's speed by a third. Nonetheless, when all her machinery was working, she made almost 300 miles a day, a creditable speed for 1850. She proved that she could achieve these respectable speeds all the way across the Atlantic when she reached New York in July 1850 only 10 days and fifteen hours after leaving her dock in Liverpool. This was just an hour and twenty minutes behind Cunard's Asia which, at the time, held the blue riband for the fastest trans-Atlantic voyage. Atlantic's speed was very competitive for her time.

Atlantic and the other Collins Line ships were more than just fast. They were among the most luxurious of their day. Consequently, traveling on them was more expensive than on lesser ships, one newspaper commenting that, "The superior comforts she offers will cause the extra $10 passage money to be disregarded." The luxuries attracted the rich and famous. Among the notables to sail on Atlantic were singer Jenny Lind, President Millard Fillmore, President James Buchanan, Vice President George M. Dallas, Ambassador to France, John Y. Mason, Ambassador to Russia Thomas H. Seymour, Gaetano Bedini, the first Papal Nuncio to the United States, theater entrepreneur William Niblo, and Philanthropist George Peabody.

For most of her career with the Collins Line, Atlantic rotated with Pacific, Baltic, and Arctic in regular ocean crossings. She completed a round trip, including loading and unloading in New York and Liverpool in about a month. For the most part, these trips were uneventful, but within her first year she suffered a major breakdown. Atlantic left Liverpool on December 29, 1850, and soon encountered stormy weather and rough seas. On January 6, 1851, the drive shaft for her starboard paddlewheel broke, and in doing so, wrecked several related pieces of machinery before the engine was shut down. Her captain ordered the crew to send up the yardarms for her square-rigged sails hoping to sail to Halifax or New York. The wind turned contrary, however, and the ship was forced to sail back to Europe. She arrived in Cork, Ireland on January 22, 1851. Her passengers were transferred to other ships, and Atlantic was towed to Liverpool for repairs.

It took a half year to repair the ship. While waiting for her engine to be repaired, a new dining room, suitable for serving 200 guests, was constructed on the spar deck. The old dining room, one level down on the main deck, was converted into rooms for 80 additional passengers. She arrived back in New York on August 3, 1851, to resume her monthly sailings, and although she was withdrawn from service periodically for repairs and upgrades, Atlantic continued them with regularity through 1857.

Atlantic had a minor scrape on April 28, 1852, when she ran aground in a dense fog near Killmore. She was able to work her way back into deep water and arrived at Liverpool the next day. She went aground again, this time on Sandy Hook, New Jersey, in March 1854. This was a particularly unlucky trip. While she floated off at high tide, she went aground again the next day after clearing customs in New York Harbor.

The North Atlantic was typically stormy during the winter months, so while Atlantic might carry over two hundred passengers on a summer crossing, there might be fewer than fifty willing to brave the discomfort and risk of a winter voyage. Several winter sailings were delayed by ice on the Hudson River.

The Collins Line suffered a number of setbacks in the mid-1850s. It lost Pacific and Arctic to shipwreck. In August 1856 Congress reduced the mail subsidy, which had risen to $858,000 per year, back to its original $385,000. The surviving ships, Atlantic and Baltic, were worked hard for less profit. In March 1857, Atlantic was withdrawn from service for repairs and was replaced by a chartered ship which was slower and less luxurious, eroding the Collins Line's reputation for superior service. Atlantic returned to service in late June 1857, but she was becoming less attractive to customers. Newer vessels, such as Vanderbilt, were speedier. On January 6, 1858, Atlantic returned to New York from Liverpool for the last time as a Collins Line steamer. She had completed 55 trans-Atlantic roundtrips, the most of any of Collins' ships. The Collins Line was bankrupt.

On April 1, 1858, Dudley B. Fuller, acting on behalf of the Brown brothers, was the sole bidder for Atlantic, Baltic, and Adriatic at a sheriff's auction. He bid only $50,000 which left various government and private creditors seeking recompense, mired in failed sale attempts and litigation for years.

North Atlantic Steamship Company (18591860) In 1859, the first trans-continental rail line was still a decade away. The fastest way to travel between the east and west coasts of the United States was to take a steamer from New York to Panama, take the Panama Railroad across the isthmus, and then take another steamer to San Francisco. Prior to 1859, the Pacific Mail Steamship Company served the west coast part of this route while the U.S. Mail Steamship Company served the east coast portion. Both lines depended on the subsidies from the U.S. Post Office for their profitability. When these contracts were due for renewal in 1859, the U.S. Mail Steamship Company chose to sell its assets and retire from the business. In response to losing its Atlantic partner, the Pacific Mail Steamship Company created the North Atlantic Steamship Company in conjunction with the Panama Railroad. The steamship company contributed $400,000 in cash, while the railroad contributed $500,000. The new company bought the three remaining Collins Line ships, including Atlantic, from the Brown brothers in 1859 for $900,000, half in cash and half in Pacific Mail Steamship Company stock.

Atlantic was extensively modified for her new job. New cabins were built on her spar deck for first and second class passengers, while the staterooms on the main deck were removed to create space for hundreds of steerage berths.

On October 20, 1859, Atlantic put to sea for the first time in a year and a half. She sailed from the former Collins Line wharf at the foot of Canal Street for Aspinwall, Panama. She was no longer a luxury liner for a few dozen rich and famous. She had on board perhaps 1,000 people, including 250 troops from the U.S. Army's Fourth and Ninth Regiments bound for General William Harney's command in the Pacific Northwest. She arrived back in New York on November 10, 1859 with 340 Californians returning to the eastern United States, and $1.6 million of their gold.