The following poem “The Republic” was written by Longfellow in 1850 when the nation was fracturing over the issue of slavery. [The anti-slavery Whigs converted into the Republican Party in February 1854.] It was a time in the life of the Republic that inspired naming of the new clipper ship , 'Great Republic' launched in 1853. Portions of Longfellow's poem follow.
The following poem “The Republic” was written by Longfellow in 1850 when the nation was fracturing over the issue of slavery. [The anti-slavery Whigs converted into the Republican Party in February 1854.] It was a time in the life of the Republic that inspired naming of the new clipper ship , ‘Great Republic’ launched in 1853. Portions of Longfellow’s poem follow.
Thou too, sail on, O Ship of State!
Humanity with all its fears
With all the hopes of future years,
Is hanging breathless on thy fate!
We know what Master laid the keel,
What Workmen wrought thy ribs of steel.
Our hears, our hopes are all with thee,
Our hearts, our hopes, our prayers, our tears,
Our faith triumphant, O’er our fears,
Are all with thee,-are all with thee!
This merchant ship sailed from Boston in December 1853 to the cheers of 30,000 to 50,000 spectators present because Boston had declared the day a public holiday. Sailing through New York it reached London in 1855 as reported in the Illustrated London News on which this article is based. An abridged portion of the news item announcing its arrival in London follows.
“This gigantic vessel—partly destroyed by fire soon after she was built, during a great conflagration in New York, having had her damages made good, arrived in the Thames on her first voyage last week: having made the run from New York to Scilly in thirteen days, and beat up Channel to the Downs in three days against the heavy east winds which have been prevailing. She is at the present exciting much interest, from her immense proportions and peculiar rig, as she lies at her moorings off Purfleet.
On boarding her, one is struck with her enormous width of beam, which equals that of the largest line-of-battle ships afloat: in consequence of her immense beam she cannot enter either of the docks here; and, drawing with her cargo nearly twenty-five feet, she is compelled from insufficient depth of water high up to discharge her cargo in the Long Reach; but it is intended when that is accomplished to bring her up to moorings at Blackwall. She is 3400 tons burthen: 305 feet long; 53 feet beam; hold 30 feet; and has come here ballasted with 3000 tons of guano..” She required 1.5 million feet of pine, 2056 tons of white oak, 336.5 tons of iron, and 56 tons of copper. She is the largest sailing ship in the world.” 
Deducing her voyage for this article was like pulling one protruding string from a skein. With three 216-feet tall masts a side wind would topple her were it not for ‘ballast’ of 3000 tons of guano in her 30 foot deep hold. At that time guano, the excrement of primarily bats and cormorants [11-16% nitrogen, 8-12% phosphoric acid, and 2-3% potash ] was used in the manufacture of gunpowder.
Reaching Scilly marked its sailing time of thirteen hours because this archipelago is the southernmost tip of England. It is a chain of several islands 80 miles southwest of Saint Isaac, Cornwall, actual location of the fictional town of Portwenn, site of ‘Doc Martin,’ popular PBS television series.
As a sailing ship it depended on vagaries of wind and weather. Reaching Cornwall on the southwest corner of England it sailed on to the southeast corner to “The Downs” on the southeast point of England where it would begin its voyage up the Thames estuary into London—its destination. The Downs was a staging area in the Atlantic where ships set at anchor awainting their turn to sail up the Thames. [At one time 800 ships were anchored there.] Being too deep in the water to sail into central London she first had to lighten her load.
She first had to go to Gravesend a short distance up the southeast side of England. It was a port city of the London Port Authority Pilot Station meaning where she had to take on an English pilot experienced at sailing ships up the Thames into central London. It is also where Native American Pocahontas died and was buried in 1617.
She then sailed on to Purfleet. Why? It was built as a site for six powder magazines holding up to 60,000 barrels of gunpowder protected by a fort. Also, they likely made their gunpowder using guano such as the Republic’s ballast. Unloading it there decreased the ship’s draw to enable it to sail into central London.
Finally the shipped reached its destination of Blackwall, a dock on a sheltered loop of the Thames next to the London District of Poplar—location of the true story portrayed in the popular PBS series, “The Midwives.” When you see Jenny biking through all those heavy-set men with a ship’s smoke stacks in the background, they are probably stevedores on the Blackwall dock. It was constructed by the East India Tea Company which played a prominent part in the Boston Tea Party that contributed so heavily to the beginning of the American Revolution.
That’s all I could glean from the thread I pulled from that article in the 1855 book I recently purchased at a garage sale here in Shawnee.
 The Illustrated London News [weekly], Vol.26, Jan-June, 1855,