Battle between the Argentine Confederation Army and the Empire of Brazil Navy in 1851, at El Tonelero pass on the Paraná River, during the Platine War
The battle decided control of the Tonelero pass on the Paraná River, enabling the Brazilian fleet to advance and decisively shift momentum in the Platine War.
Key Facts
- Date
- 17 December 1851
- Argentine cannon rounds fired
- More than 450 rounds
- Brazilian sailors killed
- 4 killed
- Argentine soldiers killed
- 8 killed
- Argentine artillery pieces deployed
- 16 guns
- Argentine troop strength
- 2,000 soldiers
By the Numbers
Location
Cause → Event → Consequence
During the Platine War, Brazil sought to project military power along the Paraná River into Argentine Confederation territory. The Brazilian Imperial Navy needed to break through the fortified Tonelero pass to land troops and support allied forces operating against Juan Manuel de Rosas. Argentine commander Lucio Norberto Mansilla held the pass with artillery and infantry to prevent the passage.
On 17 December 1851, eight Brazilian warships under John Pascoe Grenfell attempted to force the Tonelero pass near the cliff of Acevedo on the western bank of the Paraná River. Argentine forces fired over 450 cannon rounds for approximately one hour, killing four Brazilian sailors and wounding five. The warships returned fire, killing eight and wounding twenty Argentine soldiers, then broke through.
After the Brazilian squadron passed the defenses, commander Mansilla believed the Brazilian infantry division would land directly on his main position and fled, abandoning all artillery and equipment. The fleet landed troops at Diamante, Entre Ríos, and returned to bring additional battalions from Colonia del Sacramento, strengthening the Allied coalition's position against Rosas in the wider conflict.
Belligerents & Mobilization Analysis
Side A
1 belligerent
Lucio Norberto Mansilla.
Side B
1 belligerent
John Pascoe Grenfell, Marques de Sousa.