His naval policy was to construct two ships for each one Chile built, and he went on to turn the Peruvian Navy into the most powerful in South America.
He acquired the frigates Mercedes, Guisse, Gamarra, Amazonas, and Apurimac and the schooners Tumbes and Loa.
Castilla also acquired the first steam-powered warship of any South American country and named her Rimac.
For the defense of the Amazon, Castilla began to develop an Amazonian fleet with the purchase of the ships Morona, Pastaza, Napo, and Putumayo.
[19] Both vessels were built in parts in England in 1862 and assembled in Puno on Lake Titicaca.
[26] ex-US Cannon-class destroyer escorts (sometimes known as Bostwick class), 1,900 tons full load.
[23][26] ex-US LSM type medium landing ships, 913 tons full load.
[23] ex-US Terrebonne Parish class landing ships, 5,800 tons full load.
[19][44] ex-Russian tankers, Grigoriy Nesterenko type transport oilers, 28,610 tonnes dwt.
[19] ex-US Apache (or Cherokee) class fleet ocean tug, 1,675 tons full load.
[23] ex-US Maricopa (orSotoyomo) class auxiliary ocean tug, 853 tons full load.
[19] Amazon flotilla water barges acquired in 1972, 300 tons standard load(?
[19] ex-Dutch Carrasco class survey ships, 343 tons ex-Dutch van Straelen class former inshore minesweepers converted to survey ship role,[19] 169 tons full load.