t'AND AND WATEK 
January 9, 1915. 
Kowerer, & distance of 487 mileo was flown by tbe Italian air- 
man, Deroye, on July 17, 1913, this being the record, up to 
date, of a non-stop flight in a straight line. We can thus, 
until any further record is established, assume that no existing 
•eroplane can, with a reasonable margin of safety, undertake 
« flight over the sea of a distance greater than 400 miles. 
The conclusion is, therefore, that, for the present, the radius 
of action of an aeroplane flying over the sea is about 200 miles. 
If we now examine some airship records, we find that 
the French airship, Adjudant-Vin^enot, left its shed at Toul 
on June 20, 1914, and made a non-stop voyage in a circuit, 
passing over Toul, Oommercy, Verdun, Sedan, Mesieres, 
Maubeuge, Oompi6gne, Palis, Versailles, Paris, Meaux, 
Chalons, Vouziei-a, Montmedy, Longuyon, Nancy, Neuf- 
chateau, Mireoourt, Commercy, Toul, thus showing that, for 
a considerable part of its journey, it must have travelled with 
the wind. 
On that voyage, which lasted 35hr. 20min., the airship 
carried a crew of eight, besides Captain Joux, who was in 
command. This performance of the Adjudant-Vincenot is 
the record for duration in a "closed circuit" voyage, that 
is, one in which the airship eventually returns to its start- 
ing-point. Recently the Zeppelin L.Z.24 remained in the air 
for 34hr. and 59 min., travelling in various directions over 
Germany. It did not, however, n.ake a " closed circuit," for 
it started ita voyage at Friedrichshafen and ended it at Johan- 
nistal. 
RADIUS OF ACTION OF THE 
ZEPPELIN. 
In examining duration records, it is important to bear in 
mind the fact that the sustentation of an airship, or its 
power to remain aloft, is independent of its propulsion. It 
is, therefore, possible for the airship to remain aloft without 
the working of its motor, or motors, thus economising fuel 
whenever it is possible. The aeroplane, however, has to work 
ita engine during the whole of its flight, for, without propul- 
sion of its own, it has no sustentation. Therefore, it follows 
that in establishing duration records, an airship may take 
advantage of the wind to go from one place to another; so 
that a duration record of this type of aircraft is evidently 
considerably greater than the length of time of its possible 
navigation under full power. Also, when concerned solely in 
the establishment of a duration record, the airship has not 
on board a full crew, as would be necessary for prolonged mili- 
tary observations, nor has it a supply of projectiles and of 
ammunition. Under such conditions a greater amount of fuel 
can be carried than would be possible when the airship is out 
for a military cruise. In these circumstances it can be as- 
sumed, with a fair degree of accuracy, that the probable dura- 
tion of an airship voyage under full power is, at present, about 
one-third of the record times already mentioned, that is, one 
of about twelve hours. A Zeppelin, having a speed of fifty 
miles per hour, would thus be able to travel, under war con- 
ditions, a distance of about 12 x 50 = 600 miles. Conse- 
quently its radius of action would be about 300 miles. That 
of the aeroplane ia, as already shown, only 200 miles. The 
importance of these figures, and of the airship's possible in- 
fluence on the North Sea operations, will be readily grasped 
if reference be made to the sketch-map on the previous page. 
THE ZEPPELIN IN THE NORTH SEA. 
The Island of Heligoland, ofif the coast of Germany, is 
not only a naval base, but also the most up-to-date Zeppelin 
station. From it a modern Zeppelin can undertake cruises of 
considerable length over the North Sea, and can survey the 
greater part of that portion of the Atlantic Ocean. Indeed, 
an airship, having a radius of action of 300 miles, can travel 
from Heligoland to any point bounded by the arc, Z, Z, Z. 
From any position on that arc, Z, Z, Z, a Zeppelin, at a. 
height of, say, 4,000ft., could, in fine weather, make observa- 
tions over a further distance of twenty-five miles, so that, 
although the range of action of a Zeppelin from Heligoland 
would be limited by the arc, Z, Z, Z, its range of observation 
would extend up to the arc, O, 0, 0. The section-lined area, 
contained by the arcs, 0, O, O and Z, Z, Z, is a belt which, 
under normal conditions of wind and weather, would be be- 
yond the radius of action of a Zeppelin, but over which it 
would be able to keep watch. Zeppelins, stationed at Heligo- 
land, could, therefore, observe over the thousands of square- 
miles of sea area whicli lie between the arc, 0, O, O, and the 
coast of Continental Europe. 
Observation, carried out by the Zeppelin over the North 
Sea, could not be sent by wireless telegraphy unless the air- 
ship were within the cross section-lined area, bounded by the- 
arc, W, W, W, and the mainland of Europe. The radius 
of the arc, W, W, W, is 150 miles, which is the range of th& 
wireless telegraphy apparatus fitted on a modem Zeppelin. 
If a Zeppelin, therefore, has made an observation beyond 150 
miles from Heligoland, it would have to return to within that 
range before it could send its wireless message. This is an 
important point to remember in dealing with the new factor 
wliich has been introduced into naval warfare by the advent 
of aircraft, for it shows that it is only within the arc, 
W, W, W, that a Zeppelin can maintain contact with its ad- 
versaries and Headquarters. 
If we now examine the radius of action of the aeroplane 
from various points of the English coast, we shall see that, 
with an aviation base near Sheerness, observations can be 
carried out within the area contained by the arc. A, A, A. 
From a point near Cromer aeroplanes can scout the sea area^ 
within the arc, B, B, B. With Scarborough as centre, obser- 
vations, by means of aeroplanes, can be carried out within 
the arc, C, C, C, and, from a point near Peterhead, aero- 
planes can make observations within the arc, D, D, D. 
Of all the various circles that can be described with a- 
ra<lius of 200 miles about a centre lying on the English coast, 
the one drawn from a point near Cromer cuts the greatest^ 
area of the Zeppelin wireless zone. This is useful to note. 
Another point of practical importance is that there is a» 
zone in the north-east of the North Sea which can be scouted 
by means of Zeppelins stationed at Heligoland, bi'.t which 
cannot be reached Ly aeroplane from the British coast. That 
zone is denoted by dotted lines in the sketch. 
THE LOSS OF THE "FORMIDABLE." 
By COL. F. N. MAUDE, C.B. (late R.E.). 
THE heavy loss of trained and most highly eBcctive 
seamen, which seems to form an inevitable feature 
of the sinking of any of our warships, simply 
compels one to ask the question, whether, in fact, 
all means of keeping our fighting vessels afloat 
after 6-ubmarine attack, in any of its forms, have 
been considered, and put through a fair and conclusive trial. 
I make no apology for venturing outside the usual 
limitations of my articles, for the subject has interested me 
for years, and aa an officer of the Royal Engineers, a corps 
formerly entrusted with the business of submarine coast de- 
fence, it was part of my duty to make myself thoroughly 
familiar with the problems involved in modern battleship 
building, and in particular to follow all the records of ex- 
periments made with submarine mines against such vessels 
which from time to time the Admiralty placed at our dis- 
posal. The Oberon and the Resistance are the first two whose 
names recur to me. 
I saw 5001bs'. gun-cotton mines exploded under them at 
different times, afterwards studying their effect in dry dock, 
and I was as convinced then as I am now that even that 
charge should not necessarily send a ship (such as we were 
then building) to the bottom, or such as we have since built, 
unless the mine happens to explode the ship's magazine, as it 
would appear does occasionally happen, though theory is quite 
powerless to explain the how or why of this occurrence. But 
service in India called me away, and it was only after tlio 
Japanese War that I approached Sir William White, v.ho had 
just retired from the Admiralty, and discussed my scheme 
with him. Unfortunately, we differed fundarntiitally on 
facts of which I had been an eye-witness and he lia J not seen, 
and again, since the matter was not one in which I was 
directly concerned, I allowed my patent to lapse, and re- 
solved to stick to my own last. 
My idea was exceedingly simple, and can be tested by 
anyone who will try to force an empty biscuit tin, mouth 
downwards, in his bath — when the resistance he will encoun- 
ter will astonish him. 
It was not applicable for mci'chaiit steaiiieis, because, r.» 
a rule, it is uneconomical to subdivide them by a horizontal 
plane, which interferes with tlio facility of loading and un- 
loading cargo. But all our warships, from small protected 
cruisers upwards, are so subdivided by tho armour plate 
turtle-deck running riglit through them from bow to stern, 
and beneath which all the engines, boilers', magazines, etc., 
are always placed. This turtle-deck is pierced with hatch- 
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