As the earlier discussion of the geography of the Atacama region illustrates, control of the sea lanes along the coast would be absolutely vital to the success of a land campaign there
Bulnes, Gonzalo (1919). Guerra del Pacífico(PDF) (in Spanish). Vol. 3: Ocupación del Perú – La Paz. Valparaíso: Sociedad Imprenta y Litografía Universo.