Fortress of Humaitá

The site was a sharp horseshoe bend in the river; practically all vessels wishing to enter the Republic of Paraguay – and indeed to steam onwards to the Brazilian province of Mato Grosso – were forced to navigate it.

The fortress was protected from attack on its landward side by impenetrable swamp or, where this was lacking, defensive earthworks which, at their greatest extension, comprised a system of trenches stretching for 8 lineal miles (13 km), had a garrison of 18,000 men and deployed 120 cannon.

However the fortress, though not by then invulnerable to the latest armour-plated warships, was a serious obstacle to the Allies' plans to proceed upriver to the Paraguayan capital Asunción and to recapture the Brazilian territory of Mato Grosso: it delayed them for two and a half years.

[21][22][23] Professor Williams' assessment: "In an attempt to coerce Paraguay economically and bring it to its knees, Buenos Aires only stiffened Paraguayan nationalism and produced a voluntary, xenophobic isolation of the breakaway province".

[32] During his presidency there were conflicts, not only with Brazil and Buenos Aires, but also the United States: the USS Water Witch affair of 1855 in which the fort of Itapirú [es] fired upon an American warship,[33] which led to a US naval expedition against Paraguay in 1858.

[36][49] To a design by the Hungarian colonel of engineers Wisner de Morgenstern [es],[50][51] he hastily fortified the river's left bank with a few batteries, which were continually but slowly augmented, and a trench was dug on the land side enclosing the rear of them.

As described by an eyewitness aboard USS Fulton, part of the Paraguay expedition sent by President Buchanan to demand reparations for wrongs alleged to have been done to the United States Sixteen ominous apertures pointed their gloom, and whatever else they may contain, upon us; and, like the eyes of the figure in the picture, seemed to follow the vessel's motion ...

[61][62] An unpleasant surprise for an invading flotilla was that, owing to the peculiar conformation of the river bed, there were "treacherous backwaters which often neutralize the action of the rudder, in direct proportion to the length of vessels".

The outline measures nearly eight miles and a half, and encloses meadow land to the extent of 8,000,000 square yards – a glorious battlefield.The 200-yard wide navigable channel ran close to the east bank i.e. the river batteries.

[72] Other sources,[80] notably George Thompson (de facto chief engineer of Paraguayan army) wrote that there were three chains side-by-side, of which the heaviest had 7.5 inch links, sustained by barges and canoes.

[81] The official staff report of Allied force that captured Humaitá, dated 29 July 1868, by Cordeiro Torres e Alvim [pt], said that on both banks of the river there were seven chains which, after entering the water, were bound to three.

[82] Before even arriving at the Vuelta de Humaitá an invading squadron would first have to navigate the River Paraguay from its mouth, and run the gauntlet of such batteries as the Paraguayans were able to deploy on its left bank, particularly at Curuzú and Curupayty.

Their guns and ammunition were not shipped until they arrived at Corrientes; for the Paraná is equally shallow in various parts...It is difficult to conceive a more formidable obstacle to an advancing squadron than this small portion of the river between Tres Bocas and Humaitá.

[92] The fuses were designed and made by George Frederick Masterman, chief apothecary to the Paraguayan Army:[93] they were glass capsules of sulphuric acid which, when broken by striking a heavy object, ignited a potassium chlorate/sugar mixture.

Much of it was protected naturally by carrizal,[109] marsh or swamp, and where not, an elaborate system of trenches was constructed, eventually extending over 13 km (8 mi) with palisades and chevaux-de-fríse at regular intervals,[110] known as the Quadrilateral (Cuadrilátero,[111][112] Polígono or Quadrilatero in various language sources).

[139]In order to gradually map the area the Allies were obliged to resort to mangrullos (improvised watch towers)[140][119] or (a first in South American warfare) captive observation balloons,[141][142] but the Paraguayans obscured the terrain by lighting fires of damp grass.

[157] Wooden paddle-steamers, if intending to proceed into Paraguay, would have had to steam, against the current, past the succession of batteries – where the range was 200 metres (660 ft) or less[158] – and somehow cut through the boom of twisted chains, without being sunk: this appeared to be impossible.

I had seen it compared with Silistria and Kars, where even Turks fought; with Sebastopol in her strength ...; with the Quadrilateral which awed Italy; with Luxembourg, dear to France; with Richmond, that so long held the Northerners at bay; and with the armour-plated batteries of Vicksburg and the shielded defences of Gibraltar.

Can these poor barbettes, this entrenched camp sans citadel— which the Brazilian papers had reported to have been blown up —be the same that resisted 40,000 men, not to speak of ironclads and gunboats, and that endured a siege of two years and a half?

When Burton inspected them (August 1868) he noted that many had been thrown into deep water but the remainder were poor:[165] The guns barely deserve the name; some of them were so honeycombed that they must have been used as street posts...[166] Not the worst of them were made at Asunción or Ibicuy, whose furnaces and air chimneys could melt four tons per diem.

[167][168] The gunboat HMS Dotterel, while anchored at Humaitá for three hours in June 1865, from the river counted 116 guns, a number far greater than was recorded by Burton or Jourdan when inspecting the captured fortress.

The Londres work, besides being in a state of decay, was an exposed mass of masonry which ought to have shared the fate of forts from Sumpter to Pulaski, and when granite fails bricks cannot hope to succeed.

News of this naval engagement arrived in the River Plate on 14 May 1862 and was reported in the Buenos Aires Standard in these terms:[178] The two steel vessels commenced a cannonade a mile apart, without doing any damage on either side.

The chain was thus buried some two feet under the mud of the river, offering no obstacle whatever to the navigation.Because the marshlands were not ideal for the raising of cattle or the cultivation of manioc or maize, and because the Quadrilateral required a large garrison, food for Humaitá needed to be brought in from elsewhere.

Besides they would be already fortified and intrenched before the Brazilians could arrive in any considerable numbers, and then, having shown the world their strength, and demonstrated to Brazil that they were not to be conquered except at ruinous cost and sacrifice, the Imperial government would be glad to treat for peace on terms highly advantageous to Paraguay....

Thus Solano López's reckless actions brought about the very thing that most threatened the security, even the existence, of his country: a union of his two powerful neighbours.... For John Hoyt Williams, Humaitá was instrumental in generating the risk-taking behaviour:[196] The hundreds of heavy calibre guns mounted at Humaitá and elsewhere, the modern navy, railroad, telegraph, and munitions manufacturing establishments – all helped to bring about the horrendous War of the Triple Alliance and their own destruction by providing the hardware with which Francisco Solano López could become the Mariscal and self-appointed arbiter of the Río de la Plata.

[198]A possible alternative view is that López was aware that developments in naval warfare were making Humaitá obsolescent and so decided to take the offensive before Paraguay lost the balance of advantage altogether.

[202] Indeed, López himself only eight months after the Battle of Hampton Roads was pressing the American ambassador in Asunción to procure a monitor for him;[203] and Paraguay placed orders for several ironclads to be built in European or Brazilian yards before the War.

Their ability to manoeuvre depended excessively on the level of the river, which between September and March could fall as much as fourteen feet, restricting the navigable channels and increasing the perils from obstructions or sandbanks.

These difficulties are almost sufficient to account for the failure of the allies to bring about the quick decision that their overwhelming superiority in numbers and armament entitled them to hope for, but they were also handicapped by divided leadership, national jealousies and as time went on a sinking morale.