January 23, 1915. i 
LAND AND WATER 
explosivo effect of >a inine is intensely local, and if only it can 
be kept twenty or thirty feet from tlie side of the ship, its 
destructive energy becomes practically innocuous. 
Admirals and other naval experts often object to nct- 
dofenoe on tho ground that it is cumbersome and difficult to 
handle, that it is, under modern conditions, largely inefiective, 
and that it tends to interfere with the speed and manoeuvring 
qualities of tho ship— but in reply it may be said that these 
nets and thoir supports can easily bo designed so as to become 
completely effective for the purpose proposed, and that it is 
better to loso a few knots' speed, notably within the narrow con- 
finea of tho North Sea, than to lose the vessel itself ; and there 
can, I fear, bo littlei ' doubt but that we shall continue to be 
horrified by news of fresh naval disasters, and the still more 
irreparable loss of gallant lives until our naval authorities 
taka into more serious consideration this most pressing prob- 
lem of Net-Defence.— Yours faithfully, 
Arnold F. Hills,- M.I.N.A. 
Hammerfieldj Penshurst, Kent. 
RUSSIA AND AVIATION. 
To tho Editor of Land ani> Watee. 
Sir, — Having lately como over from Russia on important 
business wliich has kept me very occupied, I was fortunate 
enough in a spare moment to read Mr. L. Blin Desbleds'' 
article on " The Airship in Naval Warfare," published in 
your esteemed journal of January 9th, 1915.' 
With all due respect to Mr. Desbleds, with whom I am 
eomevvhab- acquainted through correspondence, I cannot agree ■ 
wHh his views on tho subject treated -by him ia the befora- 
mention«d article.- 
Having had inttimate experience of dirigiblesi or 'airships 
for many years I may state that the capability of the airship 
to remain stationary over any given-point is extremely pro- 
blematical. In practice I have never seen it done in average 
weather or even under the ideal conditions of the White 
Nights of Northern Russia, better cotiditions than which it is 
impossible to find, except perhaps on the paper of the mathe- 
matician. 
When attempting to keep- an airship stationary over any 
given point, instead of doing so the airship, even whan oa its i 
best behaviour, drifts slightly about in every direction, with-' 
out any definite wisk of it-s own -as- it -were, the toy of every 
phenomenon of tho element in which it floats, and not even 
superior management of tho vessel will fully counteract this 
behaviour, which those having deep practical experience of 
airships know to be sufficiently Aggravating and disconcerting 
when endeavouring to do witii accuracy anything requiring 
this quality of remaining stationary, which the airship is gene- 
rally supposed to possess, such work can be better carried 
out when the airship has a certain amount of engine-driven, 
accurately-gauged headway 1 
Under tlie genei-al term of aeroplaiiej it ia apparent from 
Mr. Desblbds' article that he compares the small type of aero- 
plane generally known with the modern airship, quite ignoring 
tho existence of the large 400-h.p. to 900-h.p. aeroplanes, an 
equally modern de\"elopment, which Russia, keeping its own 
counsel, has brought to a high pitch of perfection during the 
past two or three years, and with which I have had also much 
to do. 
The comparison made by Mr. Desblftds is unfair, as these 
large aeroplanes are as superior for general utility to their 
small sisters as the modern airships are to the early smaller 
airships. 
These large aeroplanes can be made so to hover as it were 
o\«er any given point, as to attain very similar conditions to 
tho3o obtained on an airship having a very slight amount of 
headway as aforesaid, for periods of time amply sufficient for 
thoir operators, wilh the modem perfection of instruments, to 
falfil with accuracy anything which previously it has been sup- 
posed could bettor be accomplished on airships, when trying 
to make them remain stationary over a given point. 
These large aeroplanes are fittod with four engines, and 
have a speed of seventy miles per hour, and can be made to 
fly non-stop, whenever so required, for twelve hours, and they 
can bo a* easily navigated at night fdr such periods as in the 
d&ytirae. Thc!y have ample crew accommodation, and carry 
an instalfetion of "wireless telegraph with a range of not less 
than 200 miles, searchlights, machine guns, bomb-dropping 
apparatus, and photographic laboratory. 
Such aeroplanes have proved their complete superiority 
to airships, and their nsft during this war ha»- brought great 
ben?fit to Russia, and tho .sooner Great Britain has such 
iaachii>«8 tho beiter. — I am. Sir, yours truly, 
0. J. H. MACITBMZn^ICENNEDr. 
Member of Technical Committee,*' 
Imperial All-Russia Aero Club.' 
33, St. SwHhin.!* Lano, Loadon, E.Ci ■ 
PROTECTION AGAINST SUBMARINES. 
To the Editor of Land and Water. 
Dbae Sir, — I enclose a memo, re submarines. I havo 
already sent the substance of it to the Admiralty, but it was 
mixed up with other proposals, and not so clearly put as' 
it now is. They do not consider the idea practicable. I 
have asked them, whether I may communicate my ideas to 
the Press, as'some others have done, and they agree. 
I should be extremely glad if you would (in Land and 
Water) give, briefly, your ideas on the proposal. I know 
you take great interest in such matters. Various similar 
ideas were commented on in The Times in November. 
1. Main Idea.^^-The idea is to arrange so that- a submstriiie, 
in fairly shallow or confined waters, shall notify its pre- 
sence and its whereabouts. It is proposed to lay down wires 
which the submarine will touch and breafc or displace'. 
Since the- vertical height from- keel to top of periscope is 
considerable, a system of horizontal wires would bo raosb 
efficient. 
2. Wires. — To bo laid horizontally one above anotlier, 
and at such intervals — say 25 feet — that a submarine- must 
strike one or other. To be suspended at suitable intervals 
by cords or wires from floats. To be anchored at tho ends 
and at other points if necessary. See sketch Figi 1. Lengtli 
of a wire not to be so great as to seriously retard the sub- 
marine, oUierwise the latter would become aware of the^fact 
that it was entangled and might go astern, and shake oS the 
wire. 
3. Indicator Floats. — A submarine striking a wire would 
double it up and carry it along. Connected with ' each 
end float there would be an indicator float (A, fig. 1 and 2), 
which would remain on the surface and move along in wake 
of submarine and show a flag. A watching destroyer could 
follow. At night tho float could carry a lighter be coated 
■with luminous paint. 
4. Remarks. — Wires could be laid acrosa mouths of har- 
bours, etc., or around selected areas of sea (e.g., areas near 
Belgium wlien ships shell the coast), or even right across 
the Straits of Dover. The south part of the North Sea is 
only about 120 feet deep. The wires would be in lengths, 
eaoB overlapping the next. They would be more simple 
than a system of nets such as has been proposed. In some 
cases it might be suitable to attach the ends of the wires 
strongly to the shore. The breaking of the wire might in- 
terrupt an electric current, and so signal the presence of tho 
submai'ine. Of course ships crossing the wire would have to 
stop engines and slow, - 
E. S.- BBLaASH, M.I.C.K. 
30; Lansdotm Crescent, Cheltenham, 
15* 
