Question: The Battle of Vuelta de Obligado was part of a larger naval blockade that lasted how long?

Context paragraphs:
Donato Álvarez: Donato Álvarez (1825 – September 23, 1913) was an Argentine general.  He fought in the battle of Vuelta de Obligado under the command of Lucio Mansilla.  He joined Justo José de Urquiza in his conflict against Juan Manuel de Rosas, and fought in the battle of Caseros.  He also fought in the Paraguayan War and the Conquest of the Desert.  He died in Buenos Aires in September 23, 1913.

National Sovereignty Day: The National Sovereignty Day (Spanish: "Día de la Soberanía Nacional" ) is a national public holiday of Argentina, celebrated during November 28.  It commemorates the Battle of Vuelta de Obligado, when a small Argentine army stood against an Anglo-French navy that broke into the Paraná River on November 20, 1845, against the will of the Argentine Confederation.  Although the battle itself ended with an Argentine defeat, the losses of Britain and France in the whole military campaign were so high that both countries were forced to the bargaining table and signed a treaty with Juan Manuel de Rosas.  The day was enacted as a national observance in 1974, following a request from the revisionist historian José María Rosa, and promoted into a national holiday in 2010.

Astley Cooper Key: Admiral Sir Astley Cooper Key (18 January 1821 – 3 March 1888) was a Royal Navy officer.  As a junior officer he saw action at the Battle of Vuelta de Obligado in November 1845 during the Anglo-French blockade of the Río de la Plata and took part at the Battle of Bomarsund in August 1854 and the Bombardment of Sveaborg in August 1855 during the Crimean War.  He also went ashore with the naval brigade to take part in the Battle of Canton in December 1857 during the Second Opium War.  He later commanded a specially-formed Baltic Fleet created in February 1878 to intimidate Russia from entering Constantinople during the closing stages of the Russo-Turkish War.  He became First Naval Lord in August 1879 in which role he was primarily interested in administration and technology rather than strategy: he kept the cost of running the Navy within budgets, sanctioned the construction of six Admiral class battleships and ensured the Navy was properly prepared for the Panjdeh Incident in 1885 when Russian forces seized Afghan territory at Panjdeh.

John Edmund Commerell: Admiral of the Fleet Sir John Edmund Commerell, (13 January 1829 – 21 May 1901) was a Royal Navy officer.  As a junior officer, he was present at the Battle of Vuelta de Obligado in November 1845 during the Uruguayan Civil War.  He also took part in operations in Sea of Azov during the Crimean War and went ashore with the quartermaster and a seaman, to destroy large quantities of enemy forage on the shore.  After a difficult and dangerous journey they reached their objective – a magazine of corn – and managed to ignite the stacks, but the guards were alerted and immediately opened fire and gave chase.  The men had difficulty in escaping, but they finally reached their ship and the lookouts later reported that the forage store had burned to the ground.  He and his colleague, Quartermaster William Thomas Rickard, were awarded the Victoria Cross, the highest award for gallantry in the face of the enemy that can be awarded to British and Commonwealth forces.

Battle of Vuelta de Obligado: The naval Battle of Vuelta de Obligado took place on the waters of the Paraná River on 20 November 1845, between the Argentine Confederation, under the leadership of Juan Manuel de Rosas, and a combined Anglo-French fleet.  The action was part of the larger Anglo-French blockade of the Río de la Plata.  Although the attacking forces broke through the Argentine naval defenses and overran the land defenses, the battle proved that foreign ships could not safely navigate Argentine internal waters against its government's wishes.  The battle also changed political feeling in South America, increasing support for Rosas and his government.

Martiniano Chilavert: Martiniano Chilavert (October 16, 1798 – February 4, 1852) was a 19th-century Argentinian military officer who took in the part in the country's civil wars between the Unitarians and the Federales.  Originally an Unitarian opponent of Federalist leader of Juan Manuel de Rosas, Chilavert joined the federalists after the Battle of Vuelta de Obligado.  Chilavert was motivated by Rosas' resistance to the British and French and the other Unitarian leaders' alliance with non-Argentines.  The day after the day after the Battle of Caseros, he was shot without a trial on the orders of Justo José de Urquiza.

Alsogaray: Alsogaray is a Basque surname.  A branch of the family emigrated to South America in the early 19th century, and sustained a military tradition for several generations, beginning with Coronel Álvaro José Alsogaray's role in the 1845 Battle of Vuelta de Obligado.  Some members of the Alsogaray family became famous in Argentina due to their involvement in critical events in Argentine history.

Lucio Norberto Mansilla: Lucio Norberto Mansilla (April 2, 1789 – April 10, 1871) was an Argentine military man and politician.  He was the first governor of the Entre Ríos Province and fought in the battle of Vuelta de Obligado.

Anglo-French blockade of the Río de la Plata: The Anglo-French blockade of the Río de la Plata was a five-year-long naval blockade imposed by France and Britain on the Argentine Confederation ruled by Juan Manuel de Rosas.  It was imposed in 1845 to support the Colorado Party in the Uruguayan Civil War and closed Buenos Aires to naval commerce.  The Anglo-French navy trespassed into the internal waters of Argentina, in order to sell their products, as Rosas maintained a protectionist policy to improve the weak Argentine economy.  Eventually both Britain and France gave in, signing treaties in 1849 (Britain) and 1850 (France) acknowledging the Argentine sovereignty over its rivers.

James Hope (Royal Navy officer): Admiral of the Fleet Sir James Hope, GCB (3 March 1808 – 9 June 1881) was a Royal Navy officer.  As a captain he was present at the Battle of Vuelta de Obligado during the Uruguayan Civil War and then in the Baltic Sea during the Crimean War.

Supporting paragraphs: Battle of Vuelta de Obligado Anglo-French blockade of the Río de la Plata
Answer: five-year-long