 Aretusa was armed with a main battery of one 120 mm ( 4 @.@ 7 in ) / 40 gun and six 57 mm ( 2 @.@ 2 in ) / 43 guns mounted <unk> She was also equipped with three 37 mm ( 1 @.@ 5 in ) / 20 guns in single mounts . Her primary offensive weapon was her five 450 mm ( 17 @.@ 7 in ) torpedo tubes . The ship was protected by an armored deck that was up to 1 @.@ 6 in ( 41 mm ) thick ; her conning tower was armored with the same thickness of steel plate . 
