 The Nagato @-@ class ships ' waterline armor belt was made from Vickers cemented armor and protected 137 @.@ 14 meters ( 449 @.@ 9 ft ) of the hull between the barbettes of the end turrets . The lower strake was 305 mm ( 12 in ) thick , 2 @.@ 7 meters ( 8 ft 10 in ) high , and tapered to a thickness of 100 mm ( 3 @.@ 9 in ) at its bottom edge ; above it was a strake of 229 mm ( 9 in ) armor that was 1 @.@ 7 meters ( 5 ft 7 in ) high . Approximately 1 @.@ 77 meters ( 5 ft 10 in ) of the armor belt was below the waterline . The turrets were protected with an armor thickness of 305 mm on the face , 230 – 190 mm ( 9 @.@ 1 – 7 @.@ 5 in ) on the sides , and 152 – 127 mm ( 6 @.@ 0 – 5 @.@ 0 in ) on the roof . The barbettes were protected by armor 305 mm thick , while the casemates of the 140 mm guns were protected by 25 mm armor plates . The sides of the conning tower were 369 mm ( 14 @.@ 5 in ) thick . 
