Mine (naval weapon)

“ Men were busy at the stern of the ships watching the wooden kites that are made so as to catch the mines by the hawser that is slung between the two steamers. The slightest sign of a ball-like piece of steel in the sea and the dullness of sweeping is relieved, for then the skipper knows that he has unhooked one of the mines. Along came a submarine, flying the white ensign of the Royal Navy. The mine-sweepers realise that these men have no arm-chair job, and admire the commander and crew of the under-water boats accordingly. ”

“ Linder?” drawled the visitor.
“Huh?” returned the Honorable William Linder, startled.
“Submarine mines,” explained the other., “Mines in the sea, if you wish words of one syllable.”
The lids of the Honorable Linder contracted.
“You’re in the wrong joint,” he said, “this ain’t the Naval College.”
“Thank you. A submarine mine is a very ingenious affair. I’ve recently been reading somewhat extensively on the subject. The main charge is some high explosive, usually of the dynamite type. Above it is a small jar of sulphuric acid. Teeth, working on levers, surround this jar. ”

“ Hartley, pointing to the circular mine. "These horns are usually called studs. Hit one of these studs even a light blow with a tack hammer, gentlemen, and the mine would explode. A mine like this is more deadly than the biggest shell carried by a super-dreadnaught. Let this mine explode, for instance, under our hull forward, and it would tear us to pieces in a way that would leave us afloat for hardly sixty seconds. Moreover, it would kill any man standing at or near the rail over the point of contact." ”

“ In January, 1917, the only vessels equipped for this service were four merchant ships and the Flotilla Leader Abdiel, with a total minelaying capacity of some 1,200 mines per trip. It was not advisable to carry out minelaying operations in enemy waters during the period near full moon owing to the liability of the minelayers being seen by patrol craft. Under such conditions the position of the minefield would be known to the enemy. ”

“ An account is given of the mine barrage in the North Sea, one of the outstanding anti-submarine offensive projects of the year, thus closing the North Sea, and for which 100,000 mines were manufactured and 85,000 shipped abroad. A special mine-loading plant, with a capacity of more than 1,000 mines a day, was established by the Navy Department.
A star shell was developed which, when fired in the vicinity of an enemy fleet, would light it up, make ships visible, and render them easy targets without disclosing the position of our own ships at night. ”

“ A submarine mine of to-day consists of a mine case, shaped like a ball or egg, about one yard in diameter, mounted on an anchor in the form of an iron box about 30 inches square, connected by a wire rope mooring cable, about 3⁄8 inch in diameter. The mine case contains the charge of high explosive—300 pounds of TNT in our mines—and the firing mechanism. The combination stands about 5 feet high and weighs 1400 pounds. Four small car wheels on the anchor run on steel tracks, allowing the mines to be easily moved along the decks to the launching point. ”

“ A barrier of high explosive across the North Sea—10,000 tons of TNT, 150 shiploads of it, spread over an area 230 miles long by 25 miles wide and reaching from near the surface to 240 feet below—70,000 anchored mines each containing 300 pounds of explosive, sensitive to a touch, barring the passage of German submarines between the Orkneys and Norway—this was the final five months’ contribution of the American and British mining forces towards bringing the war to a close. ”

“ But as the laying of mines, speaking generally, is a defensive 21mode of warfare and the policy of the British Navy—owing to its supremacy—is attack and not defence, the mine-laying fleet is of second importance to the sweeping fleet, the work of which, although much augmented by additional small steamers pressed into service, was, during the first few weeks of the war, of a nature more arduous and dangerous than will ever be realised. ”

“ A mine, as the reader probably knows, is a cask filled with high explosives and fastened by means of weights and anchors so that it floats some feet below the surface. Mines can be planted in fields, as it were, by torpedo-boats or submarine and then a hostile fleet can be lured or chased in among them. The North Sea, as we know, is at present thickly strewn with them and fatal results have already been chronicled. Air-ships and aeroplanes can help by finding the whereabouts of the hostile fleet and designating by wireless the spots where the mines should be planted. ”

“ After a study of the various types of mines in existence, there was produced an American mine believed to involve all the excellent points of mines of whatever nationality, while another extraordinary [Pg 54] invention was the non-ricochet projectile. The ordinary pointed projectile striking the water almost horizontally is deflected and ricochets. A special type of shell which did not glance off the surface of the ocean was developed early in 1917 and supplied to all vessels sailing in the war zone. ”

“ After an hour at last sighted the minesweepers, which had already started work.'
"One may judge of these North Sea activities from the record of a single lieutenant of the Naval Reserve who, besides attending to other matters, destroyed forty or fifty mines, twice drove off an inquisitive German Taube, attacked an equally inquisitive Zeppelin, twice rescued a British seaplane and towed it into safety; rescued in June the crew of a torpedoed trawler, sixteen men, also the crew of a sunk fishing vessel; in July assisted two steamers that had been mined, saving twenty-four of the sailors ”

“ In planning mining operations in the Heligoland Bight, it was necessary to take into consideration certain facts. The first was the knowledge that the Germans themselves had laid minefields in some portions of the Bight, and it was necessary for our minelayers to give such suspected areas a wide berth. Secondly, it was obvious that we could not lay minefields in areas very near those which we ourselves had already mined, since we should run the risk of blowing up our own ships with our own mines. ”

“ Submerged mines are more dangerous to the enemy because they cannot be seen and avoided. They should float far enough under the surface to remain hidden and yet not so deep that a shallow-draft ship can pass over them without hitting them. As the sea bottom may be very irregular, it is impossible279 to tell how long the anchor cable should be without sounding the depth of the water at every point at which a mine is planted. ”

“ The fire of our destroyers sank two of the mine-sweepers, and the others, though badly damaged, were enabled, owing to their light draught, to escape across the minefield, where our deeper craft could not follow. The mine-sweepers were escorted by destroyers and submarines, which did their utmost to torpedo our ships, but failed to accomplish their purpose. Sometimes, however, the enemy had better luck, as when they torpedoed the Mentor while she was escorting one of our mine-layers in the Heligoland [66] Bight. ”

“ Mines for the open sea in great numbers, moored “flying”—that is, by ships steaming at considerable speed—need anchors with automatic depth regulation. Such mechanism had undergone important changes during the war, and the new American mines needed all the improvements, to make them sure to plant at the intended level. ”

“ They explode immediately on being struck by a passing vessel, and, of course, do not discriminate between friend and foe. The systems of destroying hostile mine-fields consist of counter-mining, or placing other mines in the enemy’s field and destroying it by 170their explosion, and by sweeping. The latter method is the one mostly employed in modern warfare. The boats taking part in the sweep place themselves one on each side of the mine-field, and between them hangs a long wire rope, weighted in the centre to keep it well submerged. ”

“ One struck the hull just below the water-line on the starboard side, nearly abaft the foremost funnel; the second bumped heavily under her port quarter. Practically simultaneously the deadly mechanical mines exploded. ”

“ The Entente when laying their minefields displayed the same ruthlessness towards free shipping and the lives of neutrals.
Mines are considered as a recognised weapon for the definite protection of the home coast and ports, also as a means of blockading an enemy port. But the use made of them as an aggressive factor in this war is quite a new feature, for vast areas of open sea on the route of the world's traffic were converted into minefields impassable for the neutrals except at the greatest danger of their lives. ”

“ A Dutch Mine-sweeper engaged in clearing the North Sea of German Mines PARAVANES
On the other hand, the Allies had a way of sailing right through fields of enemy mines with little danger. Our ships were equipped with "paravanes" which are something like the "water kites" used by mine-sweepers, and289 they are still used in the waters of the war zone. Paravanes are steel floats with torpedo-shaped bodies and a horizontal plane near the forward end. ”

“ Counter-mining.All mines, especially those with electric cables attached, must be protected by gun fire or guard boats, as, if the mine field is un protected, they can be easily destroyed by countermining or creeping. Countermining is carried out by exploding a succession of charges in an enemy's mine field. Mines containing heavy charges would be used for the purpose, several of these mines being dropped in succession from a boat towed by a fast steamer, the whole line being exploded together as soon as the last mine had been dropped. ”

“ It seldom happens that a vessel strikes a mine dead on the bow or stem-post. The cushion and dislocation of water formed by a big and fast ship around its bows is usually sufficient to cause the mine to swing a few inches away from the bow and to return and strike the ship several feet back on the port or starboard side. A careful study of Fig. 30 will show how this is prevented by the deflecting wires of the paravane. ”

“ The great minefield which was declared by our Government in the summer of 1917, the preparation of which was a gigantic undertaking, extended from the Frisian Islands to about latitude 56 degrees north. The Dutch, for their own purposes, removed their lightships from their coasts to the western side of this minefield, thus forming a line of lights running north and south, roughly along the 4th degree of east longitude. This our sailors facetiously named Piccadilly Circus. It was the business of the submarines to lay mines on the eastern part of this minefield, that is, near to the coast. ”

“ This class of mine is used in side channels which it is intended to close entirely, or to reduce the width of navigable channels where too wide to be defended by observation mines. Their principal advantage is that if the firing switch is closed they are effective in fog or mist, when observation mines could not be worked, and when the guns of the defence would be equally out of action. As they are fired only when close against the side of a ship, the charge can be comparatively small and the mines themselves are handy and easy to lay. ”

“ Mines of any kind are exceedingly difficult to render efficient when the water is over 100 feet deep. On account of the tendency of all high explosives to detonate by influence or sympathy, and the liability of the cases to collapse by great exterior pressure, harbor mines are separated a certain distance, according as they are buoyant or ground, and according to the nature of the explosive.
Five hundred pounds buoyant gun-cotton mines require 320 feet spacing. ”

“ The cable is carefully insulated and protected with a layer of steel wires. An earth return is used for the electrical circuit.
The employment of mines in any defence must depend entirely on the general character of the defence adopted, which will itself depend on the size and importance of the harbour to be defended and other details (see Coast Defence) . The role of mines in a defence is to act as an obstacle to detain ships under fire and compel them to engage the artillery of the defence. Thus mines find their greatest usefulness in the defence of harbours with long channels of approach. ”

“ In the ground mine, the case contains the explosive and the firing device, and is heavier than the displaced water; it therefore rests upon the bottom and requires no anchor. Ground mines are not used where the depth of water exceeds 35 feet. ”

“ The system of defence consists of the mooring of these mines in such positions as to make it almost impossible for hostile ships to pass without either striking or coming within the destructive zone of one or more of them. What are known as floating mines are those set adrift to be washed about by the tide. ”

“ Ten ships laden with high explosive, navigating in mine-swept channels, in submarine thoroughfares, and near minefields beyond sight of fixed marks—compactness of the minefield demanding that the layers steam as near together as safe—necessity for keeping together in fog, darkness, or submarine attack—these were the conditions governing our tactics. ”

“ As you can tell by its name a contact mine is one that is exploded by the hull of a ship coming in contact with it—that is, by running against it. This is the kind of mine that is most often laid by the submarine.
An electrically controlled mine is one that is exploded by electricity. For this purpose a pair of wires are connected to it and these lead along the bottom of the harbor to two observation stations on the shore; when the enemy ship gets directly over the mine the observers close the electric circuit and the mine is exploded. ”