Sinking of the Ostfriesland
On July 20, 1921 the Navy brought out the ex-German WWI battleship, Ostfriesland, considered unsinkable. One day of scheduled 230, 550 and 600 lb. bomb attacks by Marine, Navy and Army aircraft settled the Ostfriesland three feet by the stern with a five degree list to port; she was taking on water. Further bombing was delayed a day by rough seas.
On the morning of July 21, five NBS-1 bombers each dropped a single 1,100 lb bomb, scoring three direct hits. By noon, Ostfriesland had settled two more feet by the stern and one foot by the bow. At this point, 2,000 lb bombs were loaded and a flight of three Handley-Page O/400 and eight NBS-1 bombers led by Capt. Walter Lawson dropped six in quick succession, aiming for the water near the ship. There were no direct hits but three of the bombs landed close enough to rip hull plates as well as cause the ship to roll over. The ship sank in 21 minutes, with a seventh bomb dropped on the foam rising up from the sinking ship.[4] Nearby the site, observing, were various foreign and domestic officials aboard the USS Henderson. One man present was a representative of the Japanese navy: Captain Osami Nagano. Nagano was quoted in a local paper as saying there was "much to be learned here."[citation needed] Years later, Nagano helped plan the Japanese attack on Pearl Harbor.
Although Mitchell had stressed "war-time conditions", the tests were under static conditions and the sinking of the Ostfriesland was accomplished by violating agreed-upon rules that would have allowed Navy engineers to examine the effects of smaller munitions, though the rules were changed right before the 2,000 bombs were to be dropped; Mitchell's airmen disregarded the rule and quickly sank the ship in a coordinated attack. Studies of the wreck of the Ostfriesland show she had suffered little topside damage from bombs and was sunk by progressive flooding that might have been stemmed by a fast-acting damage control party on board the vessel. Mitchell used the sinking for his own publicity purposes, though his results were downplayed in public by General of the Armies John J. Pershing who hoped to smooth Army/Navy relations.
Nevertheless, the test was highly influential at the time, causing budgets to be redrawn for further air development and forcing the Navy to look more closely at the possibilities of naval airpower.[5] Despite the advantages enjoyed by the bombers in the artificial exercise, Mitchell's report stressed facts repeatedly proven later in war:
...sea craft of all kinds, up to and including the most modern battleships, can be destroyed easily by bombs dropped from aircraft, and further, that the most effective means of destruction are bombs. [They] demonstrated beyond a doubt that, given sufficient bombing planes—in short an adequate air force— aircraft constitute a positive defense of our country against hostile invasion.
The fact of the sinkings was indisputable, and Mitchell repeated the performance twice in tests conducted with like results on obsolete U.S. pre-dreadnought battleship Alabama in September, 1921, and the battleships Virginia and New Jersey in September, 1923.[6] The latter two ships were subjected to teargas attacks and hit with specially designed 4,300 lb demolition bombs.
