What the clearance of these vast fields of floating and anchored mines in the North Sea meant to the British Navy, engaged in blockading the German Fleet, and to the Mercantile Marine not only of England, France, Russia and Belgium, but also to that of the neutral countries, it is perhaps a little difficult to realize until one remembers that several hundred British and French warships were patrolling the North Sea and Channel, and, at the opening of hostilities, there were hundreds of merchantmen homeward bound whose course lay across this mine-infested sea. Many of these vessels had on board not only valuable cargoes of food, raw material for manufacture and gold and silver bullion, but also officers and men returning from various parts of the world to rejoin their regiments. Again, the Expeditionary Force had to be transported across the Channel to France. This could not be attempted until a guarantee had been given by the Navy that the seas were clear of hostile warships, submarines and mines. The fleet blockading the Frisian coast had to be supplied with coal and fresh food; and last but by no means least it was of vital importance to the Allied Armies in the Field that the whole coast-line from Bordeaux to Antwerp, forming the rear and left-flank, should be accessible to friendly shipping. It is not difficult to realize what would have been the effect had thousands of these deadly German contact mines been allowed to float unhindered in these narrow seas, for, notwithstanding the magnificent effort made by thousands of seamen in hundreds of mine-sweepers assisted by seaplanes, many vessels—some belonging to neutral powers and others to the enemy themselves—were destroyed before the seas could be effectively swept clear, the hostile mine-layers destroyed or chased into port and there blockaded with their cowardly fleet.
The torpedo has long been recognised as one of the most effective of naval arms. It is carried by every modern warship afloat, but it is essentially the arm of the submarine and of the small and fast surface vessel. For a torpedo attack to be successful it is absolutely necessary for the vessel carrying the weapon to get within about 1,000 yards of the object of attack. The difficulty of accomplishing this manœuvre with an enemy on the alert is easily apparent, but if the attacking vessel can creep up to within torpedo range unobserved her chances of sinking the enemy are decidedly good, and it is the quality possessed by the submarine of making herself invisible by sinking beneath the surface and approaching her enemy “seeing but unseen” that makes this type of vessel the ideal torpedo-boat. But, like everything else, there are limits to its use, for a submarine, although it can navigate on the surface like an ordinary torpedo-boat, cannot deliver a submerged attack at night owing to the periscopes, which are the “eyes” of these underwater fighting ships, being useless in the dark. When night covers the sea, however, the chances of the fast grey-painted surface torpedo-boat or destroyer being able to approach the enemy unseen are more than doubled, and in this way fleets become exposed to submarine torpedo attack by day and surface torpedo attack by night. Further, a submarine will often attack while a seaplane hovers over the enemy in order to draw attention. It is this constant exposure to sudden and unseen submarine attack which is primarily responsible for the terrible nerve strain imposed on the crews of modern surface warships in time of war.
Owing to the ability of submarines to deliver stealthy attacks by day, naval tacticians have designated this type of craft “Daylight torpedo-boats,” but they are rapidly passing beyond the purely torpedo and coastal defensive stage and are taking on to themselves the rôle of the ocean cruiser. The size of these vessels has increased from 50 to 1,000 tons displacement in ten years. They now carry not only a considerable number of the largest size torpedo but also quick-firing guns for repelling attacks by small surface vessels, and are capable of accompanying fleets to sea. The Australian naval submarines A.E.1 and A.E.2 both made the voyage from Barrow to Sydney under their own power and without convoy. The radius of action of the latest vessels both of the British and French Navies amounts to several thousand miles. In the case of the British “F” class the displacement has risen to 1,500 tons, the speed to 20 knots and the armament to six torpedo tubes and four 12-pounder quick-firing guns, thus making them in every sense ocean cruisers capable of keeping the sea in almost any weather and possessing wide range of action and considerable offensive power. Hitherto British submarines, like the ordinary surface torpedo-boats, have been known by numbers only, but the latest vessels are to receive names which indicates the increase in size and importance of these craft. They may be termed the advance guards of the submarine battleships of the future.
The torpedo, which is the principal arm of the submarine boat, is itself a submarine projectile. After being discharged from the firing tube it sinks a short distance below the surface and is propelled by its own engines at a high rate of speed in a straight line towards its object of attack. Great improvements have been made during the past ten years in the construction of these delicate weapons. The extreme effective range and speed has risen from 4,000 yards at 18 knots to 7,000 yards at 45 knots or 11,000 yards at 30 knots. The “war-head” or front section of the torpedo contains a charge of about 200 pounds of damp gun-cotton which is fired by a detonator on the torpedo striking an object. This very powerful explosive charge is capable of tearing open an enormous hole in the unprotected under-water skin of the surface warship. The type of weapon used in the British, French, Russian and Japanese Navies is the Whitehead torpedo (18-inch and 21-inch). The German Navy uses the Schwartzkopf torpedo (18-inch and 21-inch), which is very similar to the Whitehead and is a very powerful weapon.
In the first phase of the naval war no less than eight warships have been sunk by submarine torpedoes.
The activity of the British submarines in the theatre of war, from the beginning of hostilities, is admirably set forth in the following dispatch from Commodore Roger B. Keyes, C.B., which is the first dispatch in the history of naval warfare to describe in detail submarine attack and reconnaissance:—
H.M.S. Maidstone,
17th October, 1914.
“Sir,—In compliance with Their Lordships’ directions, I have the honour to report as follows upon the services performed by the Submarines since the commencement of hostilities:—
“Three hours after the outbreak of war, Submarines E.6 (Lieutenant-Commander Cecil P. Talbot), and E.8 (Lieutenant-Commander Francis H. H. Goodhart), proceeded unaccompanied to carry out a reconnaissance in the Heligoland Bight. These two vessels returned with useful information, and had the privilege of being the pioneers on a service which is attended by some risk.