THE GLOBE. THURSDAY, JULY 15, 1880.

Globe, Volume XXII, Issue 1994, 15 July 1880, Page 2

THE GLOBE. THURSDAY, JULY 15, 1880.

The report by Colonel Scratchley on the Defences of New Zealand has been presented to Parliament, and will be found to contain much useful, it might almost bo said, invaluable information. The subjects treated of are handled in a practical spirit, and although to some parts of the colony the report may be disappointing, yet the public at large will not fail to recognise its worth. Wo say “ some parts of the colony,” because Colonel Scratchley has been forced to the conclusion that the only places that can at present be defended—taking into consideration the matter of expense—are Auckland, Wellington, Christchurch, Dunedin, and possibly Invercargill. Starting on the assumption that one or two cruisers, and possibly an ironclad, would bo the largest force that would be likely to bo sent into these waters, the remainder of the enemy’s fleet being engaged in fighting with the English fleet nearer homo, the Colonel recognises the fact that they might occupy one of the minor harbours such as Russell, Tauranga, Nelson, Picton, or Akaroa, with a view to making special preparations for an attack upon one of the largo ports above referred to, or they might issue from them to capture passing vessels, or again them might lie olf such roadsteads as are to be found at Gisborne, Napier, Timaru, or Oamaru, for the purpose of levying contributions. But the only way in which such operations could be counteracted is, says Colonel Scratchley, by naval means, for the country cannot at present afford the outlay necessary to prevent, by batteries and torpedoes on these spots, the occurrence of such contingencies. With regard to the defence of harbors in general the descriptions of defence are three—lst, by battery ; 2nd, by torpedoes; 3rd, by torpedo boats. There are two descriptions of batteries for such service, the one involving the employment of bomb-proof chambers or casemates, whore, unless the bomb-proof roofs and the fronts of the casemates are destroyed, the guns cannot bo silenced, and the other batteries on the harbette principle. The former description has the advantage that the guns can bo placed near to the level of the sea with perfect security, but the expense is too groat for our resources, so that the barbette principal will have to bo adopted. By this method the guns ,

fire over an earfchorn parapet, and the lateral range of each piece is greatly increased ; fewer men are required, and the guns are placed at a higher level above the water, so as to compensate largely for the loss of complete cover by the increased difficulty which the ship experiencos in replying to their fire. Under the protection of the guns on the works on shore, submarine mines or torpedoes are generally placed in those channels by which an enemy must pass in order to enter the ports. Colonel Scratchley then proceeds to enumerate the three kinds of fixed or defensive torpedoes : —the observation, the electro-contact, and the mechanical. Those are generally distributed in three or more rows across the channel. The observation torpedoes are fired by observation, that is to say, at the will of two observers on shore, situated at convenient distances apart, and in telegraphic communication with each other. “Electrocontact mines are self-acting when in an active state, and are intended to explode when struck by the hostile vessel in passing over them. They are, however, completely under the control of the observer on shore, who can render them passive at any time to permit of friendly ships entering the port.” The mechanical mines do not require connection with the shore, but are fired on being struck by internal mechanism. They are, however, almost equally dangerous to friend or foe, and even the work of removing them is attended with groat risk. All three descriptions of submarine mines can be guarded against, and possibly rendered harmless by an active enemy by the processes of countermining, creeping and sweeping. Countermining is the process of destroying the defenders’ mines by the explosion of heavy charges in their vicinity. Creeping is the process of removing the mines by dragging for them along the bottom by moans of grapnels, and sweeping is searching for the position of the mines by dragging a rope up or down a channel. Now, taking into consideration the fact that any enemy approaching our shores will bo provided with all known moans of counteracting defensive torpedoes, and further that such mines entail the employment of delicate instruments, requiring skilled hands and steady cool heads for their manipulation, it is evident, thinks Colonel Scratchley, that efficient and reliable defences of this description could not be established without the most careful preparation, and without the services of a large body of men trained for the work, “ the difficulty lying not so much in the application, as in the maintenance, of the system when established.’’ Having carefully weighed all points, the Colonel is of opinion that a complete system of submarine defences at each place could not be kept up excepting at an expense entirely beyond the power of the colony to afford. “At the same time, looking at the fact that the scheme of defence proposed cannot bo considered to be complete without submarine mines, and that, at some future time, defensive mines may be introduced, I think it advisable to establish the nucleus of a torpedo corps at Wellington, and to arrange for the instruction of a certain number of employees in the Telegraph Department.”

There remains to consider the third means of defence, namely, offensive torpedoes to support the batteries on shore. That best suited to New Zealand harbors is the spar torpedo, which can he adapted for use from boats of almost any size, such as ordinary steam launches and pinnaces. The modus operandi is, of course, by steaming on to the enemy’s ship at night or early dawn. The work is one of great danger, but it requires no special qualifications beyond those possessessed by the seamen and engineers to be found in every port. “It is possible,” says the report, “ that there are already steam launches at the ports to ho defended, which could be made available in time of war, provided an agreement were entered into with their owners, and the necessary fittings procured; but it is to bo understood that three new boats for each harbor are absolutely necessary.” Torpedo boats are admitted to he most formidable weapons against ships in the hands of daring and determined men, and they could be procured almost at once, and aro not very costly either to purchase or maintain. As far then as tho forcing of an entrance into our harbors by an enemy is concerned, our mode of defence must, according to Colonel Scratchley, he confined, for tho present at all events, to batteries and torpedo boats. But there are other ways in which an enemy might harass our [towns in time of war, and to these wo propose to revert to-morrow, glancing at the same time at tho special recommendations made with regard to the defence of Port Lyttloton, although the text of this portion of the report has already appeared in our columns.