Since the early twentieth century, the explorations in the Amazon, especially with the formation of the Board of Roads. On the other hand, under the auspices of the Government or the Geographical Society of Lima and sometimes have been made by our sailors another kind of explorations, fixing the geographic coordinates of many points of the national territory.
During these events, the borders were not well defined, that is why on several occasions the Ecuadorian troops, above all, occupied national territory without being able to be timely rejected. In the Napo river region there were fortuitous encounters between Peruvians and Ecuadorians. Lieutenant Oscar Mavila Ruiz in command of the boat "Cahuapanas" was in charge of these operations.
"Courageous Huáscar! Luck puts us for the third time in front of enemies and within a few minutes we will engage in the fight ... It does not matter that your forces are superior, because you have a much stronger heart ... and you will win because our cause is holy, and because we defend , not only the honor of our beloved homeland, but also that of a sister and allied republic, unjustly and treacherously offended by the same enemies. Crewmen of Huáscar, ¡Viva el Perú! "
(Arenga of Admiral Miguel Grau to his staff before the Battle of Pisagua, quoted in Ahumada: 1982, 398).
After the Battle of Iquique on May 21, 1879, the monitor "Huáscar" carried out operations on the Chilean coasts, such as the one carried out in Antofagasta on the 26th of the same month, against the batteries on land and the Chilean schooner "Covadonga" . Three days later, he cut the submarine cable, and with this action managed to isolate this port with Valparaiso.
However, on the 30th of that month, Admiral Miguel Grau, noticing the Chilean squad returning from his unsuccessful expedition to Callao, decided to sail from Iquique in a northwest direction, being spotted by the corvette "Magallanes" and the armored "Blanco Encalada ", Chilean ships that immediately began their pursuit. In this way, said port was again blocked on May 31 of the same year.
By June 1, the "Huáscar" was anchored in Arica, from where it left for Pisagua to load coal. At six in the morning of Tuesday 03, while Admiral Miguel Grau sailed his ship to the south, in search of the Chilean corvettes "O'Higgins" and "Chacabuco", he spotted, between Huanillos and Punta Lobos, two steamships , and believing that they could be his targets, he launched himself on his hunt. Great was his surprise when, being five miles away, he recognized that those ships were the "Blanco Encalada" and the "Magallanes", who, realizing the presence of "Huáscar", chased him again, this time for five hours. Our monitor could barely reach a speed of nine miles due to the poor quality of coal he had loaded in Pacocha and Pisagua.
The persecution stopped for a moment when at 11.30 am the "Blanco", realizing that the distance that separated him from "Huáscar" was only three miles, broke his fires against our ship (the corvette "Magallanes" did not participate in this combat). Immediately "the Huáscar staff, with a serenity worthy of the instants of test, was prepared for the combat ... and to the touch of zafarrancho each one happened to occupy his respective position".
Thus, the monitor wore three pavilions that in unison of "Viva el Perú!" responded the attacks of the Chilean armored with four shots of cannon of its tower and three with those of stern. With this, the "Huáscar" could escape without damaging its armor or affect its staff, except for the loss of a young volunteer crew member who volunteered to fight for the homeland, Antonio Cucalón, who died drowned after falling into the sea.
Later, the "Huáscar" arrived in Callao on June 7 where they made repairs to their machines.