CREATE TABLE table_26171 ("Warship" TEXT, "tons  (  L.ton  ) " FLOAT, "Horse- power" FLOAT, "Speed  (  Knots  ) " TEXT, "Armour  ( Inch ) " TEXT, "Main Artillery" TEXT, "Built Year" FLOAT)

What's Blanco Encalada's main artillery?
SELECT "Main Artillery" FROM table_26171 WHERE "Warship" = 'Blanco Encalada'
SELECT "Main Artillery" FROM "table_26171" WHERE "Warship" = 'Blanco Encalada'