April 25, 191 8 
Land & Water 
The Channel Straits: By A. H. Pollen 
THE following question has been put to me : 
" I observe that, in the current number of Land 
AND Water, your colleague, Mr. Belloc, in ex- 
plaining the enemy's selection of the Messines- 
Givenchy sector for his recent attack, points out 
that, among the arguments in its favour, 'for what it is 
worth there was the moral effect of an attack developing 
close to, and threatening that highly sensitive point, the 
straits of the Channel.' Is it not possible that he had 
something more than ' moral effect ' in view ? 
" I am driven to ask this question : Is it possible the 
enemy has some objective, altogether independent of the 
direct military advantages of his procedure ? Is he, in other 
words, trying to manoeuvre us into giving up Dunkirk, and 
then, possibly, Calais ? If there were some overwhelming 
naval advantage to be gained by the possession of Dunkirk, 
his policy might seem to be justified. Is it possible to 
state, with some precision, the change that would be brought 
about in the naval position if the enemy were either at 
Dunkirk, or at Dunkirk and at Calais ? " 
In essaying to answer this question, I shall not attempt to 
assess either the probabilit}' of or the military effect of our 
withdrawal from Dunkirk, or of our being compelled to give 
Calais to the enemy. Though the first seems to me highh' 
improbable, and the second altogether out of the question, 
all I am concerned with here is to deal with the effect their 
tenure by the enemy would have in assisting his naval opera- 
tions in impeding ours, and in giving him means, other than 
naval, for interfering with our sea traffic. Before 
attempting a reasoned answer, it might be as well to 
glance at what may be called our traditional policy with 
regard to the Dutch, Flemish, and French Channel ports ; 
for it is really to this tradition, and not to the facts of the 
situation of to-day, that we must look for the moral effect 
of which my colleague wrote last week. From very early 
times it has been taken for granted that the possession of 
these ports by an enemy must constitute a serious sea menace. 
It is largely for this reason that, ever since the fall of Napoleon, 
the maintenance of the independence and neutrality both of 
Holland and of Belgium has been a corner stone of our foreign 
policy. When, therefore, in September and October, 1914, 
the enemy, having seized Ostend and Zeebrugge, was engaged 
in a determined effort to get Dunkirk and Calais as well, the 
utmost unea.siness was created in this country. But I do 
not think many people could have stated explicitly their 
exact ground for uneasiness in the sense of being able to 
say precisely what particular naval and military operations 
the possession of these ports would have made possible for 
the enemy. People forgot that our historic attitude in this 
matter dated from the period when there were not only no 
submarines, but no thirty-knot destroyers, nor guns with 
the modern command of range, nor air power. Conse- 
quently, if it was traditional policy with us that the Dutch 
ports, the Flemish ports, and the French ports, should be 
in separate possession, and two of the groups neutral, it 
seemed necessarily to follow that, if an enemy could get 
two groups into his own possession, not must an immediate 
blow have been struck at our prestige, but some kind of 
naval loss of a serious kind would follow. Calais and Dun- 
kirk, then, grew into symbols just as Verdun did later 
on. To possess them became an end in itself, and hence 
their denial to the enemy became of crucial importance. 
As a simple matter of fact, the actual possession of Dunkirk, 
or even of Calais — viewing the thing altogether apart from 
the military consequences involved — would affect the naval 
position adversely at a single point only. And the explana- 
tion of this is not very recondite. The two governing factors 
at sea are, first, that the enemy's only free naval force is his 
submarine fleet, which is almost independent of port 
facilities, and, secondly, that outside the immediate vicinity 
of his larger ports, the enemy possesses no freedom of surface 
movement at sea at all. If you examine these propositions 
separately, their truth becomes obvious. The two main and 
most profitable fields of the enemy's submarines have been 
from the Chops of the Channel westward, and in the Mediter- 
ranean Passim. To be a thousand miles from its base makes, 
therefore, very little difference to the submarine. To give a 
submarine-using enemy a base a few miles nearer his main 
field would consequently confer no advantage on him of any 
kind whatever. 
Curiously enough, if we suppose the Channel to be the 
field of their operations, the same thing is true about the 
enemy's surface craft, though for a very different reason. 
For, as things stand to-day — and as they would stand if 
he got Dunkirk, Calais, and even Boulogne — his freedom to 
get his destroyers or other ships out of harbour can be exactly 
measured by the distance he is from the nearest British 
base. The truth of this was instructively shown last week. 
Twice in the course of a few days we heard that our ships 
had swept into the Kattegat and the North Sea, each time 
destroying German trawlers on outpost duty, and capturing 
their crews. On two other occasions unsuccessful efforts 
were made to cut off destroyers that had been bombarding 
parts of the Belgian coast, west of Nieuport. On each of 
these the enemy escaped in the darkness. The point of 
the contrast hes in this. When he is four or five hundred 
miles away from a British base, the enemy can venture out 
by daylight, so long as he does not go so far afield that he 
ma}' be cut off and brought to action before dark. If no 
British force appears in such distant waters for some days 
together, he may even venture to send out light craft, such 
as trawlers, either to lay mines or to sweep for them, or to 
engage on some other operation. But even -here he risks 
their destruction if he does so. But from Zeebrugge, which 
is less than eighty miles from Dover, he dare not venture 
out at all except by night. You never hear of German 
trawlers being raided off Ostend by Admiral Keyes' command. 
And, whenever there is news of an engagement, it is either 
a midnight or a mid-fog affair. 
Zeebrugge and Ostend 
Zeebrugge and Ostend, then, are, on the experience of the 
last three years, perfectly useless to him for any daylight 
work. They are just jumping-off places for night raids, 
and refuges into which the marauders must rush for safety 
at the first threat of attack. Observe that never yet has the 
enemy in such encounters even pretended to fight the engage- 
ment to a finish. He runs — as he did the other day — though 
he had a force of eighteen boats against a bare half-dozen: 
He cannot, from the nature of the situation, even risk delay. 
He must always fear a still stronger force coming on the 
scene. Hence, they are not bases from which systematic 
naval operations could be carried out, nor any orderly form 
of sea-pressure be put upon us by regular and methodical 
operations. The fact, then, that "we control the surface of 
the sea robs Dunkirk, Calais, and Boulogne of any surface- 
craft value to the enemy, just because they are so much 
nearer to our main base at Dover than are Zeebrugge and 
Ostend. Indeed, we can go further. If he hardly now 
dares come out of Zeebrugge, it is doubtful if he would run 
and go into Dunkirk or Calais. Neither can help him then 
with his destroyers. And, because submarines do not 
require bases into which to run for refuge, these ports are 
unnecessary to him for his submarine campaign. 
I said just now that there was one respect in which the 
possession of this strip of French coast would be an advantage 
to the enemy. It is that the blocking of the Channel at its 
narrowest parts by mine barrages would be either impossible 
or exceedingly difficult. But the possession of Dunkirk only 
would hardly affect this, for from Dunkirk to Cape Gris Nez 
is nearly forty miles ; and our estabUshment and mainten- 
ance of a barrage would not be affected unless the enemy 
occupied not only Dunkirk, but the whole coast right round 
to Boulogne. 
We may then, it seems to me, make our minds compara- 
tively easy as to the effect on the naval situation of any 
further advances of the enemy along the French seaboard, 
so far, at least, as the naval situation can be affected by 
purely naval means. But are there not other than purely 
naval means that would affect, if not our naval forces, at 
any rate, the sea traffic which it is one of the main objects 
of naval force to protect and guarantee ? The enemy, we 
are told, has been bombarding Paris with unpleasant regu- 
larity from a range of seventy-five miles. From Dunkirk to 
the Downs is not more than half this distance. Every mile 
he can push on of the twenty-five that intervene between 
Dunkirk and Calais will very nearly reduce the range of the 
Enghsh coast by an equal amount. Would it still be safe 
for ships to come up Channel aijd enter the mouth of the 
Thames ? Or would London cease to exist as a port, except 
for such traffic as could come to it north about ? Far be it 
from me to suggest the Hmits of the enemy's ingenuity in 
designing, or of his industry in producing, cannon of fabulous 
reach. But the merest tyro in the art of gunnery would be 
{Continued on page 12). 
