Author of "The Text-Book of Military Aeronautics" and "The Text-Book of Naval Aeronautics," Vice-President Aerial League of America, etc.
The operations of U-boats in American waters, which have resulted in sinking ships, and the action of Germany in extending the danger zone to American waters, have forced this country to face the U-boat problem and all its possibilities. The operations of U-boats 250 miles out at sea compel consideration of the problem from a broader standpoint.
AERIAL COAST PATROL NECESSITATES ESTABLISHING AIR STATIONS AT EVERY 20 MILES ALONG OUR COASTS
The Allies have found that the Aerial Coast Patrol to be effective must be complete. The French Minister of Marine in his published report to the Chamber of Deputies stated:
We have found it necessary to organize seaplane stations all around the coasts, so that the zone of action of each station joins that of its neighbor on the other side.
Again and again the Allies have found that an efficient Aerial Coast Patrol was a quick cure for repeated U-boat attacks in different localities.
To be efficient the Aerial Coast Patrol must operate from dawn to dusk and must be so organized that every mile of the coast is under constant surveillance, and reach 100 miles out at sea.
To have "seaplane stations all around the coasts, so that the zone of action of each station joins that of its neighbor on the other side," as stated by the French Minister of Marine, means having a station at every 20 miles. The range of vision of the observer in the seaplane, at the comparatively low altitude at which the seaplane must fly in U-boat hunting, is about 10 miles. He sees clearly 10 miles ahead, and on each side: therefore, as shown in the accompanying sketch, when two seaplanes start out from two parallel stations 20 miles apart, each covers 10 miles or so of the course, and no U-boat can escape their combined action. If one sees a U-boat or something suspicious, it leaves its course and flies towards the object, and the other two stand by, ready to lend assistance. The aim is always to capture the U-boat when possible; therefore the seaplanes summon the patrols and destroyers by wireless. But, if there is the least possibility of the U-boat escaping unless action is taken promptly, then the seaplanes drop depth bombs and fire on the U-boat with their guns. This is only one of the many methods adopted. The modus operandi in U-boat patrol is left to the chief officer of each station to decide.
The smaller seaplanes operate the same way, but closer to the shore. It is not safe for a single motored seaplane to venture beyond sight of land; therefore their course in patrolling must always be parallel with the shore.
Dirigibles patrol more or less like large seaplanes, and one of their duties is the convoying of ships in and out of ports, holding up doubtful vessels at sea and convoying them to the examining station.
Following are the official reports of the British Admiralty of the sinking of 10 U-boats, eight by seaplanes and two by dirigibles.
The first case is described as follows:
While on patrol in the English Channel a seaplane sighted a submarine eight miles away, directly in the path of an oncoming convoy of merchant-ships. The seaplane dived at 90 miles an hour. The submarine attempted to escape by submerging, but was just awash as the seaplane reached a bombing position and released two bombs, one of which exploded on the conning-tower. The seaplane dropped two more bombs into the midst of air bubbles from the collapsed submarine, which was of the largest type, carrying two guns.
The second case:
At dawn a seaplane sighted a large submarine on the surface, with a member of the crew standing by the gun. The seaplane dropped a bomb on the tail of the U-boat, and afterward photographed the sinking submarine, with a big hole in its deck. A second bomb was dropped close to the submarine's bow, and the U-boat collapsed.
The third case:
Two seaplanes attacked a large submarine travelling on the surface at 14 knots, with two men in the conning-tower, and the submarine began to sink stern first. A bomb from the second seaplane completed the work.
The fourth case:
Three patrol planes sighted a large submarine as it was submerging and dropped two bombs close to the conning-tower, causing the submarine to turn turtle and disappear in a mass of oil and wreckage.
The fifth case:
A seaplane sighted two submarines close to the surface and dropped two bombs. One bomb was ineffective, but the other hit the deck fairly amidships. The submarine was hidden by the smoke of the explosion, and when the smoke cleared the U-boat was sinking with both ends in the air.
The sixth case:
A seaplane saw the track of a torpedo fired at a merchantman. It dived toward the surface and sighted the black shadow of a submarine well below the surface. It dropped two bombs, which both exploded close to the submarine, resulting in a large quantity of oil, bubbles and wreckage.
The seventh case:
Two seaplanes sighted a U-boat on the surface and dropped a bomb each. The first bomb caused a heavy list to the U-boat, which began to sink by the stern. The second bomb exploded in the center of the swirl, demolishing the U-boat.
The eighth case:
A seaplane dropped a bomb on a submarine just emerging, and the U-boat disappeared with a heavy list to port. The pilot dropped a second bomb into the swirl, and a few minutes later a patch of oil, 150 feet long and 12 feet wide, appeared on the surface.
The ninth case:
A naval airship at midday sighted a suspicious patch of oil and circled it to ascertain the cause. Suddenly a periscope broke the surface in the midst of the oil. The airship dropped a bomb close to the periscope, and a series of bubbles began appearing, indicating that the damaged submarine was moving slowly away under water. Several more bombs were dropped in the path indicated, until satisfactory evidence was obtained of the enemy's destruction.
The tenth case:
An airship dropped two bombs over a submarine which was engaged in attacking merchantmen. Great patches of oil and bubbles indicated severe damage, and trawlers made this complete by depth charges.
DESTROYING U-BOATS IN THEIR BASES AND PROTECTING SHIPS AT SEA. OTHER PROBLEMS AND THE POSSIBLE SOLUTION
The problem of beating the U-boat may be divided into three phases, one offensive and two defensive, as follows:
(I) Protecting ships at sea,
(2) Protecting ships within 100 miles of the coast,
(3) Destroying the U-boats in their bases.
The only hope of success rests in doing all three simultaneously and on an extensive scale. The cost of tonnage already lost and being lost each month represents such an enormous intrinsic loss to the cause of the Allies that the cost of conducting intensive warfare on the U-boats is small by comparison.
DESTROYING U-BOATS IN THEIR BASES
Destroying U-boats in their bases, and in the docks where they are being built and repaired, was under consideration by the Allies before the close of the war, and promised to be most fruitful, because in the nature of prevention.
The brilliant exploits of the British Navy in blocking the channels at Zeebrugge and Ostend—which was made possible by the completeness of the photographs taken from aeroplanes—have given an indication of what can be done. Unfortunately, as has been pointed out by the British officials, the Allies did not have a large number of bombing aeroplanes to send to follow up the brilliant work of the British Navy by dropping a few hundred tons of bombs and blowing up the works, the lock gates of the Bruges Canal and Ghent Canal and the U-boats in the docks.
PROTECTING SHIPS AT SEA WITH AIRCRAFT
Protecting ships at sea with aircraft 100 miles or more from shore and on transatlantic trips is the most difficult problem of all, but is by no means impossible.
There are two methods: (1) the purely defensive, and (2) a combination of defensive and offensive. These two methods in their application can aim to (1) protect individual ships, or (2) protect shipping as a whole.
In considering any plan to protect ships at sea it must be considered that such a plan must work without:
(1) Necessitating the slowing down or stopping of ships.
(2) Cutting down the capacity of the vessel to be protected by more than 5 per cent.
(3) Requiring the services of highly trained specialists, which cannot be obtained within 12 months.
(4) Requiring the laying up of ships for changes in construction, thereby tying up the tonnage for a period of time.
PROTECTING INDIVIDUAL SHIPS
In a general way to protect individual ships what is needed is a means of enabling the captain of a ship to see the U-boat at least a mile away, and as much more as possible, so as to give time to turn the guns on it. The distance desired depends entirely on the type of U-boat attacking. The smaller U-boats, which are not equipped with guns of large caliber, can be dealt with if their presence is found out before they get within 1500 yards of a ship. The larger U-boats, which are equipped with 6-inch guns, can fire on ships, and, therefore, their presence must be detected before the ship is within range. In this case, the U-boat's guns, as well as its torpedoes, must be reckoned with. It being mainly a question of finding the U-boat before it gets near enough to attack a ship, aircraft solve the problem better than anything else.
THE USE OF SEAPLANES AND DIRIGIBLES IN PROTECTING INDIVIDUAL SHIPS IN TRIPS ACROSS THE ATLANTIC IN THE PRESENT STAGE OF DEVELOPMENT OF AIRCRAFT
While there are aeroplanes that can cross the Atlantic and dirigibles the size of Zeppelins can easily cross the Atlantic, in each case they can only do so at full speed, which is between 60 miles and 100 miles per hour, which is many times the speed of ships. The employment of large aeroplanes to escort ships would be possible by using aeroplane ships stationed or cruising every 300 miles on the Atlantic. This could not be done immediately, however, because the seaplane ships would have to built; and, of course, this brings up the subject of whether, if we could build additional ships, it would not be desirable to use the ships to transport aeroplanes to the scene of action abroad, unless flying aeroplanes over is adopted. In this case, the priority would probably have to be given to using ships to carry the thousands of smaller aeroplanes needed to maintain supremacy in the air. This matter will be discussed further in detail under the heading of "Protecting Shipping as a Whole by Establishing Transatlantic Patrol."
PUTTING AEROPLANES ON SHIPS ONLY POSSIBLE IN FEW CASES
Putting aeroplanes, especially large aeroplanes, on board ships for protection is only possible in a very few exceptional cases, when the ship is thoroughly adapted for it and aviators can be spared from other naval duties to operate the aeroplanes.
The placing of aeroplanes on board ships must be essentially for the actual fighting of U-boats in an emergency, because it increases the danger from U-boat attacks to slow down or stop a ship at sea, which would have to be done to pick up the aviators after the aeroplane had made its flight.
Many of the largest ships would permit placing a platform for launching seaplanes, and the seaplane could be launched by means of a catapult used heretofore by the United States Navy, the details of which have been made public a number of times since 1912, when the first tests were made, and are therefore public property, and it is not necessary to discuss them further here. But to pilot the seaplane would require trained pilots and expert mechanics in large number. Here we must consider the difference between merely hunting the U-boat and the actual fighting of the U-boat. In considering the hunting of the U-boat, we find that it would be necessary to launch a seaplane every half-hour during daylight, and the ship would have to be slowed down or stopped to pick up the seaplane or the aviators, or both, and slowing down the ship would increase the danger from U-boat attacks. Therefore, the plan of hunting the U-boats with seaplanes on board of the ship cannot be considered at this time.
Mr. Joseph A. Steinmetz, the president of the Aero Club of Pennsylvania, has proposed a plan to provide a sort of flexible runway which can be let down at the stern of the ship and permits the seaplane to run up to the aft deck under its own power. The idea is well worth testing. If it proves practical it will permit using small seaplanes to spot U-boats at sea, making each ship self-protecting.
If, instead of having a seaplane on board the ship, a speedy fighting flying boat or aeroplane equipped with pontoons or without them is provided, then when the U-boat is sighted, or the U-boat fires at the ship, the aeroplane is launched and the aviator flies to attack the U-boat with as large a gun and bombs as the seaplane can carry, then the equipping of ships with aeroplanes is a measure well worth considering.
In other words, this aeroplane would be only for use in emergency, when the loss of the ship and the lives of the thousands on board are at stake. In such a case, the loss of the aeroplane is a mere detail compared with the possible saving of the ship and its passengers and crew.
Having to fight both the aeroplane and the ship would prove too much for the U-boat. It would divert the attention of the U-boat's fighting crew from either, and it would invariably lead to the defeat of the U-boat.
KITE BALLOONS AND MAN-CARRYING KITES AS LOOK-OUTS FOR U-BOATS
The simplest solution to the problem of seeing the U-boat before it comes within fighting distance is the employment of kite balloons or man-carrying kites, sending them up between 1000 and 3000 feet, and scanning the water from these altitudes. When the author discussed the possibility of using kite balloons and kites for this purpose in transatlantic trips 14 months ago in the "Text-Book on Naval Aeronautics," this had never been done and was not considered practical. A great many objections were brought up, none of which were based on a thorough understanding of the problem or of the possibilities of employing kite balloons and kites. In view of the fact that British, French, and American publications have shown illustrations of kite balloons attached to ships being used as lookouts for U-boats in the protection of transports, discussing the subject briefly will not be divulging a military secret. The first report of the employment of a kite balloon to spot U-boats at sea was made a year ago, when an official report was given out by the Navy Department telling us of the rescue at sea, under adverse conditions, of a kite balloon observer by a seaman. The details made public in connection with that report, and the official photographs given out for publication later showed that the balloon employed was a very small one, and that there was a combination of minimums which worked against possible success: (1) Being small, it did not have enough lift; (2) being the first experiment, the handling of it was more or less inefficient; (3) being early morning, and the weather being chilly and stormy, the hydrogen had a minimum lifting capacity, under conditions which required the very maximum lift; (4) the squall struck the balloon before it had attained a height of a thousand feet, and caught it in the nose-down position, which tended to throw it down instead of lifting it up, as would have been the case if it had struck it with the nose up. It is necessary to discuss the minor details of that first experiment, because the seeming failure of that experiment has been a sort of legend which is used in arguments against the kite balloon. As a matter of fact, larger kite balloons, properly inflated and manned by trained personnel, have proven a great success, and, as shown by the numerous official photographs issued by the British, French, Italian and American Governments' Publicity Bureaus, they are used extensively now to spot U-boats.
There are many advantages afforded by the kite balloon for this service. The range of vision depends, of course, upon the height of the balloon, but it affords an extensive vision, such as is not afforded by anything else. From a height, any irregularity of the sea is quickly noticeable. Likewise, from a height, the ripples on the water disappear and the water is seen as a glossy surface against which the track of a periscope or the oil from a U-boat or any other disturbance on the surface of the water, such as created by a U-boat submerging and emerging or travelling close to the surface, are clearly noticeable.
However, the mission of the kite balloon and of the man-carrying kite is mainly that of looking out for the U-boats. The actual fighting of the U-boat or protecting the ship after the U-boat has been found, must be done through other agencies.
MAN-CARRYING KITES ARE AN UNKNOWN QUANTITY WITH TREMENDOUS POSSIBILITIES
Man-carrying kites are an unknown quantity with tremendous possibilities. The kite was the prototype of all aircraft; and kites have been used successfully to explore the upper air and for taking photographs from high altitudes. The man-carrying kite was used for observation purposes long before the kite balloon was adopted; but at the time when the kites were used, the knowledge of construction of heavier-than-air craft and all meteorological conditions was limited. Therefore, the man-carrying kites had many limitations. Little has been done to test the possibilities of the man-carrying kite, outside of a few attempts of private individuals, like Mr. Samuel Perkins, of Boston, and Mr. Fred J. Haworth, of Pittsburgh.
The man-carrying kite, if successfully developed, would greatly simplify the problem of supplying aerial lookouts for ships, although one cannot see at the present time how they could face all the conditions to be met at sea as easily as they are faced by the kite balloon.
PROTECTING SHIPPING AS A WHOLE BY TRANSATLANTIC AERIAL PATROLS
Protecting shipping as a whole by having transatlantic air patrols is within the immediate possibilities of the aeronautic art and science. No less authorities than Gianni Caproni, the famous designer and constructor of the Caproni machines, Handley-Page, the famous designer and constructor of the British Handley-Page war-planes, and Glenn H. Curtiss, the famous American constructor, have in the past two years expressed their readiness to build aeroplanes capable of flying across the Atlantic with an adequate margin of safety. They have, in fact, offered not only to build the aeroplanes, but also to have them flown over. Handley-Page only asked for a bonus of $2500 over the price of the aeroplane for assuming the risk of delivering the aeroplane across the Atlantic by flying it over.
We also know that some of the largest aeroplanes produced in the last six months could, with a few alterations, be adapted for transatlantic cruising.
SEVEN WAYS OF FLYING ACROSS THE ATLANTIC, AND THREE ROUTES
There are seven ways of flying across the Atlantic, and three routes, as follows:
(1) By means of large aeroplanes capable of flying the 3000 miles from New York to Ireland without stopping. The construction of such aeroplanes is considered possible by prominent aeroplane manufacturers. They will be assisted by trade-winds.
(2) By means of land aeroplanes, large or small, starting from Newfoundland and flying to Ireland, a distance of 1860 miles, without stopping. The construction of aeroplanes capable of doing this is considered easy by prominent manufacturers. They will be assisted by trade-winds.
(3) By means of flying boats and hydroaeroplanes, starting from New York and flying to Ireland, stopping to take fuel from ships stationed at every 300 miles along the route.
(4) By means of flying boats and hydroaeroplanes, starting from Newfoundland and flying to Ireland, 1860 miles, taking on gasoline from ships stationed at every 300 miles along the route.
(5) By means of land machines, large or small, flying from Newfoundland to the Azores, 1195 miles, and from the Azores to Portugal, 850 miles.
(6) By means of hydroaeroplanes, flying from Newfoundland to the Azores and from the Azores to Ireland, taking on fuel from ships stationed 300 miles apart along the route.
(7) By means of flying boats, flying from Newfoundland to the Azores, and taking on fuel there.
Different authorities prefer different methods, and they can find a great many reasons why any one should be adopted. The safest way is to prefer to try them all.
LARGE VERSUS SMALL PLANES FOR CROSSING THE ATLANTIC
In the last five years there have probably been about 25 persons who have considered the transatlantic flying seriously. More recently there was increased interest in the matter, since it represented the one solution to our sending war-planes to France in large enough numbers to deliver the decisive blow to the Germans.
There are different opinions as to whether a large aeroplane would be better than a smaller aeroplane. The large machine is more convincing to most people, but it is more difficult to get the government authorities to decide to place orders for them. The small machine, capable of a speed up to 150 miles an hour, has a great many friends—people who believe that fast small machines can easily be constructed and can cross the Atlantic in a single non-stop flight.
LAND MACHINES VERSUS FLYING BOATS OR HYDROAEROPLANES
There is also divided opinion as to whether the land machine or the flying boat or hydroaeroplane is the most efficient for the transatlantic flight.
Most aviators prefer to think in terms of flying a land machine in a single flight, some even thinking in terms of flying straight from New York to Ireland. These represent the new generation of aviators and engineers, who believe in full measures.
On the other hand, the friends of the flying boat and hydro-aeroplane have a good case. They point out that with a plane capable of landing on the water, it is possible to start from New York or Newfoundland and fly from ship to ship taking on fuel and, if necessary, changing crews.
DOUBLE CREWS NEEDED FOR LARGE MACHINES
In the case of large machines, it is of course necessary to think of having double crews, meaning for men, two pilots and two mechanics, who will take turns in piloting and caring for the machine.
The question is often asked: How will pilots know when they reach Ireland and Great Britain and how will they find the landing place?
Those who ask these questions fear that the pilots, after having flown across the Atlantic, would wreck the machines by landing on unsuitable spots.
The question is easily answered. The pilots would have to get some flying experience on the Irish and British coasts, so they would know the landing places and would find them just as pilots doing night bombing and night patrol duty find their landing places.
DIFFICULT PROBLEMS OF NAVIGATION SOLVED
Next to getting the machine and having trained pilots, the important thing is navigation.
The general impression is that it is going to be very hard to cross the Atlantic without losing one's way. On the other hand, experts, who have looked into the matter closely, consider the problem very easy to solve.
The radio direction finder is perhaps the best instrument to guide the aeroplane in flying across the Atlantic. This instrument, used on ships by the belligerent nations and said to have been used by the German Zeppelins in their raids, can easily be applied to the aeroplane, so that the aeroplane can be tuned with a given station, whether on the ship or on shore, and the aeroplane flown towards the station. The possible application of this instrument was first considered three years ago and since by the Aero Club authorities. Radio authorities whose opinion has been asked on the subject have stated that the idea is thoroughly practical.
LIFE OF A MACHINE 600 HOURS. LIFE OF A MOTOR 300 HOURS
The life of a well-built aeroplane, barring accidents, is about 600 hours of flying. The life of a motor, provided it is run throttled down, is at least 300 hours of running. It will need a motor overhauling from time to time, but they can be relied on thoroughly for this length of time. Allowing an average speed of 100 miles an hour, these war-planes would, therefore, be in good condition for flights totalling 60,000 miles. As the longest distance across the Atlantic is only 3000 miles, these war-planes could make a great many trips across the Atlantic.
DIRIGIBLES OF THE ZEPPELIN TYPE COULD EASILY PATROL THE ATLANTIC AND DESTROY U-BOATS
Dirigibles of the Zeppelin type, meaning the largest types in use, could easily patrol the Atlantic for U-boats and prevent the operations of U-boats along ship lanes. The dirigibles have an advantage over the seaplanes in that they can hover over a spot at sea and investigate without having to land. A dozen large airships costing probably not more than $25,000,000 with their hangars and all their equipment necessary would solve the problem of patrolling sea-lanes across the Atlantic better than any other agencies available at present.
TRANSATLANTIC AIR PATROL ARMED WITH DEPTH BOMBS AND GUNS
The transatlantic air patrol would have to be armed with depth bombs and the largest of the present-day guns used on aircraft. They would patrol the lanes at intervals under a system which would insure having an aircraft at every few hundred miles at all times between sunrise and sunset. This system would be one of sending out an aeroplane or dirigible every hour or so from both sides of the Atlantic, beginning during the evening, so that by sunrise the following morning the aircraft would be at different points over the shipping lanes, ready to protect the ships from U-boat attacks.
PROTECTING SHIPS WITHIN 100 MILES OF THE COAST
Protecting ships within 100 miles of the coast is the job of the aerial coast patrol, which includes seaplanes of the flying boat type, having a radius of from 250 miles to 1000 miles, and of dirigibles having the same radius, as well as smaller dirigibles having a radius of only 200 miles, which are used for convoying coast-wise shipping and patrolling along the coasts and harbors.