 The bombing tests against New Jersey were conducted on 5 September 1923 in the Atlantic Ocean off Diamond Shoals , North Carolina , by Martin NBS @-@ 1 bombers of the 2nd Bombardment Group . Observers were aboard the Army transport ship St. Mihiel . Four of the NBS @-@ 1s attacked New Jersey with 600 @-@ pound ( 270 kg ) bombs at an altitude of 10 @,@ 000 feet ( 3 @,@ 000 m ) , scoring four hits and several near @-@ misses , which caused significant flooding . Another attack was made , this time with 2 @,@ 000 @-@ pound ( 910 kg ) bombs at 6 @,@ 000 feet ( 1 @,@ 800 m ) , seven of which landed close to the ship . By this time , flooding had increased to the point that the casemate gun ports were submerged . Two more NBS @-@ 1s then attacked with two 1 @,@ 100 @-@ pound ( 500 kg ) bombs apiece ; the first two missed but the third was a direct hit . It caused a large explosion and New Jersey capsized and sank 24 minutes later . 
