The US Atlantic Fleet observes Project B. The ships pictured are, from left to right, the battleships Ohio (BB-12), Delaware (BB-28), North Dakota (BB-29), Utah (BB-31) and Florida (BB-30).
The Joint Board’s report on Project B is taken from:
“Report of the Joint Board on Results of Aviation Ordnance Tests Held during June and July, 1921 and Conclusions Reached.” US Air Service, Vol. 6 (August 1921): 19-21.
These papers have been reproduced as originally written, with spelling corrections and editorial additions highlighted and bracketed in blue. If you find any errors in my transcription, please do not hesitate to contact me.
The aviation and ordnance experiments held during June and July, 1921, are analyzed herewith. Among the findings are: “The effectiveness of the bomb carried by aircraft emphasizes necessity for the rapid development of anti-aircraft armament and for the provision of pursuit planes as a part of the fleet. Aircraft carrying high-capacity high-explosive bombs of sufficient size have adequate offensive power to sink or seriously damage any naval vessel at present constructed, provided such projectiles can be placed in the water close alongside the vessel. Furthermore, it will be difficult, if not impossible, to build any type of vessel of sufficient strength to withstand the destructive force that can be obtained with the largest bombs that airplanes may be able to carry from shore bases.”
NATURE OF EXPERIMENTS AND THE RESULTS
CERTAIN ex-German war vessels having been turned over to the United States Government in accordance with the decision of the Supreme Council as to their allocation, the Navy Department decided to comply with the provision requiring their destruction by conducting a series of experiments in which these vessels were to be sunk by gunfire or by bombs dropped from aircraft. In order that both branches of the national defense might gain the maximum benefit the Secretary of the Navy invited the Army to participate in these experiments.
In addition to the experiments with the ex-German vessels as targets, one was conducted with the ex-Iowa steaming under radio control as a hypothetical enemy. Search was conducted by aircraft and attacks made using dummy bombs from 4.000 feet altitude. This experiment was conducted with a view to obtaining information as to the effectiveness of aircraft in search operations, the ability of aircraft to concentrate for effective attack on a vessel at sea, and the percentage of hits which could be made by dropping bombs from this altitude under the most favorable conditions against a slow moving target capable of changing course at will to decrease the accuracy of bombing.
The aviation experiments were successfully conducted under the direction of the Commander-in-chief Atlantic Fleet by the Air Force of the Atlantic Fleet and a provisional Air Brigade of the Army. The Gunfire experiments were conducted by destroyers and battleship of the Atlantic Fleet.
The experiments extended over the period from June 21 to July 21, and resulted in the sinking of the ex-German vessels as indicated below:
The schedule of experiments was so arranged as to obtain the greatest amount of information for the practical development of aviation and ordnance, including weapons, their appurtenances, and projectiles. Boards of Observers were appointed by the War and Navy Departments.
The experiments definitely determined in each case that the projectiles used were superior to the defensive features of construction of the vessel attacked. It has long been recognized that the gun carried by any type of war vessel is superior at moderate ranges to the armor or protective construction of vessels of like type. In a large measure, therefore, the greatest interest in these experiments lay in the bombing of naval vessels by aircraft. The main features of this report, therefore, relate to the effectiveness of aircraft in offensive action against various types of naval vessels.
GENERAL CONCLUSION
THE Joint Board has carefully studied the reports of the Boards of Observers and as a result of such study, actual observation of the experiments by one or more members of the Joint Board, and general knowledge of the principles of war and methods of conducting war, has arrived at the following conclusions.
Within their radius of action which, relative to that of naval vessels, is extremely short the effectiveness of heavier-than-air craft carrying
-19-
large capacity high explosive bombs, depends upon —
(a) Ability to locate the naval vessel,
(b) Ability to hit the target vessel with the projectile carried,
(c) Ability of the projectile to damage or destroy the vessel.
Consideration of ability locate the naval vessel
Aircraft of any of the three general classes: Lighter-than-air ships, flying boats and land planes, either in combination or singly, have pronounced ability to search sea areas within their radii of action and to locate naval vessels operating in such areas. The high speed of aircraft and the range of visibility obtained by altitude are factors which make these craft especially valuable in the Service of Information.
Heavier-than-air craft may obtain the maximum radius of action for use in the Service of Information only by carrying additional fuel in place of heavy bombs. When armed with heavy bombs the radius of action of heavier-than-air types is inadequate for extensive search operations. Therefore, to conduct an effective attack on naval vessels it will usually be necessary to have certain aircraft for searching and others for conducting the attack with bombs.
Darkness, fog, falling or squally weather, will greatly reduce the effectiveness of aircraft in search operations. Most of these conditions likewise adversely affect surface vessels conducting such operations but not to the same extent.
The present dependability of the personnel and material of Army and Navy aircraft appears to be such as to ensure that search operations, under suitable conditions, can be conducted without an undue percentage of loss. The further development of aircraft will undoubtedly increase both dependability and radius of action.
ABILITY TO HIT THE TARGET VESSEL WITH THE PROJECTILE CARRIED
The number of dummy bombs which actually hit the target during the experiment with the ex-Iowa was a very small percentage of those dropped. Other experiments, however, showed that it is not necessary to make direct hits on naval vessels to put them out of action or to sink them provided the bombs drop sufficiently close to the vessel and the explosive charge is sufficiently large to produce a mine effort of such proportions as to destroy the water-tight integrity of the vessel beyond the control of its personnel and pumps. The effective target for the bomb being, therefore, greater than the dock area of the target vessel, the percentage of effective bombs would be greater than the percentage of actual hits.
Inasmuch as these experiments were not conducted under battle conditions it is difficult to draw conclusions as to the probability of hitting a target with bombs from aircraft while in action. Under the favorable conditions existing during the experiments — namely, stationary, or practically stationary, target, immunity from enemy interference and excellent visibility and flying conditions — the percentage of hits was greatly in excess of that to be expected under battle conditions.
The probability of hitting will be reduced in the case of a target moving at high speed on varying courses; further reduced if the target vessel is protected by effective anti-aircraft armament; and practically negligible if the target is protected by effective pursuit planes. On the other hand the probability of hitting will be increased by more efficient sighting and bomb-dropping control apparatus, by further training and further development of aerial tactics.
In the present state of anti-aircraft defense it is believed that, if an air force can obtain the mastery of the air, an effective percentage of hits can be obtained against surface vessels coming within the radius of action of bombing planes without an undue percentage of loss of aircraft. Anti-aircraft armament is in an early stage of development. The history of war indicates that means of defense develps rapidly to meet the development of offensive weapons. The effectiveness of the bomb carried by aircraft emphasizes the necessity for the rapid development of anti-aircraft armament and for the provision of pursuit planes as a part of the fleet.
ABILITY OT AIRCRAFT TO DAMAGE NAVAL VESSELS
AIRCRAFT carrying high-capacity high-explosive bombs of sufficient size have adequate offensive power to sink or seriously damage any naval at present constructed, provided such projectiles can be placed in the water close alongside the vessel. Furthermore, it will be difficult, if not impossible, to build any type of vessel of sufficient strength to withstand the destructive force that can be obtained with the largest bombs that airplanes may be able to carry from shore bases or sheltered harbors.
High-capacity high-explosive bombs hitting the upper works of the vessel are disastrous to exposed personnel, serious to light upper works. comparatively slight to heavy fittings such as guns, and negligible to turrets. The effect of direct [illegible]
-20-
completely local. The most serious effect of bombs is the mining effect when such bombs explode close alongside and below the surface of the water.
In the case of major ships the mining effect of a bomb will be materially reduced due to the ability of the personnel to free the ship of large quantities of water by means of pumps, to distribute the excess water through the various compartments and to shore up the water-tight doors and bulkheads which are in most serious danger of carrying away due to water pressure.
Aircraft, through the medium of machine guns and fragmentation bombs as well as by high explosive bombs of high capacity, possess sufficient offensive power to seriously threaten the exposed personnel of naval vessels unless such vessels are protected by pursuit planes. This emphasizes the necessity for the further protection of personnel and for the provision of aircraft carriers on which such pursuit planes may be based.
The effect of the gas bomb has mot been determined but it is believed that such bombs possess offensive power which, within the radius of action of the aircraft, is today a serious threat to vessels insufficiently protected by aircraft.
SUMMARY OF GENERAL CONCLUSIONS
At present aircraft possess the following abilities as regards operations with the fleet in areas beyond the radius of action of aircraft based on shore:
(a) Limited assistance to gunnery in the control of fire.
(b) Limited assistance in the service of information and security.
(c) Important strategical and tactical qualities in operations of coast defense.
In adequate quantities they may be the decisive factor in such operations. The availability of these qualities at present depends largely on weather conditions. The radius of action of bombing planes limits their effectiveness against naval weasels to coast defense, or base defense, in which this type is a very powerful adjunct to the present system of coast defense.
With reference to the effect of aircraft on future naval construction the Joint Board is of opinion that:
(a) The mission of the Navy is to control vital lines of transportation upon the sea. If no opposition is met from enemy naval vessels this mission can be accomplished without entering an enemy’s coast zone within which aircraft based on shore or in sheltered harbors are effective.
(b) Without an effective Navy in time of war a nation must submit to an economic blockade fatal to its trade and the importation of necessary materials for the production of war supplies.
(c) If heavier-than-air craft are to be effective in naval warfare they must have great mobility and since their radius of action is not great additional mobility must be obtained by providing mobile bases — i. e., aircraft carriers.
(d) So far as known, no planes large enough to carry a bomb effective against a major ship have been flown from or landed on an airplane carrier at sea. It is probable, however, that future development will make such operations practicable.
(e) Even in the present state of development the aircraft carrier, as exemplified by the Argus of the British Navy [A converted ocean liner, HMS Argus (I-49) was the first aircraft carrier with a full-length landing deck, capable of retrieving as well as launching aircraft. She was commissioned on 16 September 1918.], is a type essential to the highest efficiency of the fleet.
(f) Aircraft carriers are subject to attack by vessels carrying guns, torpedoes or bombs and will require, as all other types of vessels require, the eventual support of the battleship.
(g) The battleship is still the backbone of the fleet and the bulwark of the nation’s sea defense, and will so remain so long as the safe navigation of the sea for purposes of trade or transportation is vital to success in war.
(h) The airplane like the submarine, destroyer and mine, has added to the dangers to which battleships are exposed but has not made the battleship obsolete. The battleship still remains the greatest factor of naval strength.
(i) The development of aircraft instead of furnishing an economical instrument of war leading to the abolition of the battleship has but added to the complexity of naval warfare.
(j) The aviation and ordnance experiments conducted with the ex-German vessels as targets have proved that it has become imperative as a matter of national defense to provide for the maximum possible development of aviation in both the Army and Navy. They have proved also the necessity for aircraft carriers of the maximum size and speed to supply our fleet with the offensive and defensive power which aircraft provide, within their radius of action, as an effective adjunct of the fleet. It is likewise essential that effective anti-aircraft armament be developed.
The Joint Board recommends that the provisions of the previous orders of the War and Navy Departments relative to secrecy concerning the results of the aviation and ordnance experiments be rescinded and that this report, if approved by the War and Navy Departments, be issued jointly to the Press.
John J. Pershing, Senior Member.
Navy Department
Approved: August 18, 1921.
Theodore Roosevelt, Acting Secretary of the Navy
Approved: John W. Weeks, Secretary of War.
-21-