What's Blanco Encalada's main artillery?
CREATE TABLE "s_ironclad_of_chile_and_peru_at_the_begi" (
  "warship" text,
  "tons_l_ton" real,
  "horse_power" real,
  "speed_knots" text,
  "armour_inch" text,
  "main_artillery" text,
  "built_year" real
);
SELECT "main_artillery" FROM "s_ironclad_of_chile_and_peru_at_the_begi" WHERE "warship"='Blanco Encalada';