Blockade logistics from Arica to Callao

Arica’s four batteries and the presence of British, French, and American observers made its blockade both a military and diplomatic test. Reinforcements increased the fortress’s immediate defense but also enlarged the food burden of a force dependent on sea supply. Because Chile controlled the maritime approach, it could attack quickly or let the concentrated garrison consume dwindling stores. The later blockade of Callao separated Lima from outside support while Chilean land forces advanced, leaving Peruvian troops concentrated in the wrong place. Once Lima fell, the remaining Peruvian warships in Callao were scuttled rather than surrendered. Together, the two cases show how blockade effects accumulate through logistics and timing.