THE MINEFIELDS

Hokitika Guardian, 24 November 1919, Page 4

THE MINEFIELDS

' j AN EXPERT STATESMEN!'. ‘ VAST WAR-TIME WORE. The subject of the submarine mining operations in the great war was dealt with in a paper by Commander A. L. Gwynue, read before the engineering section of the British Association. It stated that in 1914 Britain found herself with a small force of minelayers, a relatively small stock of deep-sea mines, and the intention of using these against enemy warships. Ur mines for the defence of ports there were none, although there still existed some material, discarded in 1906, and not yer destroyed. Meantime, Russia and Germany were fully prepared with large -stocks of efficient mines, and every warship below the size of the last armed cruiser fitted to lay mines. It was clear that both those countries intended mining against vessels, and that the very first naval operation of the war would be for the purposes of mine-laying. Such operations actually took place, and a German mine-layer was sunk by British, forces within a few days of the outbreak of hostilities. Italy and. Austria were nearly as well prepared. France and America seemed not to have looked upon the mine as taking an important place in their naval policies. On the German side, after the first three months of the war, no mines were laid by surface craft, except for a few exploits by raiders. The low degree of command of the sea by Germany precluded surface minelaying anywhere near the British coastline, and necessitated mine-laying by submarines. All systms of mining came under the headings of controlled or noncontrolled mines, and were further subdivided into contact or non-contact firing, and, finally, to moored, ground, and drifting mines. It had been necessary during the war to mine in as shallow a depth as 15ft of water, and although no mines had actually been moored in a greater depth than 200 fathoms, a demand arose for mining in 600 fathoms, for which a British design was successfully adopted, but the armistice prevented its application. In all,, some 300,000 mines and their accessories were produced, and of these 130,000 were laid by British forces, in- : eluding 15,000 in the northern barrage, I 42,000 in the eastern end of the Engj lish Channel, 12,000 off the Yorkshire coast, 10,000 in home waters, and 8000 ■ in the Mediterranean. The maximum rate of production attempted in this country was 10,000 per month, a figure that was limited neither by strategic conditions nor manufacturing limitations, but by the laying capacities of the vessels available. The production of this quantity involved the employment of some 980 firms. The cost of the British “H”. mine worked out at ! about £7O per mine in 1918, of which the amonial filling accounted for £24. The cost of the automatic sinker for use with this mine averaged £42. The “M” mine cost on an average £2OO, including its 5,0001 b charge of T.N.T. About four-fifths of the mine-laying was carried out by the converted merchantmen, whose sole purpose was to lay mines. A number of the later coastal motor-boats were fitted for laying mines, and had they become available, would have been employed in mining in German harbours. Mining from aircraft at present did not appear to possess great possibilities* and it had to be concluded that mining in any waters which watercraft could reach could be more swiftly and accurately carried out by them. The future might hold great possibilities in that respect. Hitherto, mine-sweeping had riot been reduced to a degree of simplicity that seriously menaced the value of the mine. The protection of ships by structural means had made progress but no vessel yet built looked upon meeting a mine with equanimity. The protection of vessels by the paravane was the most noticeable, anti-mining measure, and would largely reduce the value of the contact mine, hut countermeasures were possible, though they might not now he discussed. The mine achieved, perhaps, the greater part of. its results by moral, not by material effect. As a means of actually destroying submarines, the mine shared the first place with the depth-charge, and those two weapons between them accounted for one-third of the total number of submarines lost by the enemy. However, no perfect mine had yet been invented.