Читать книгу New lands within the Arctic circle - Julius Payer - Страница 5

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1. Although it be impossible to give any one, who has not with his own eyes seen the Arctic Sea, a perfectly clear conception of its character, the phenomena described in the preceding chapter are sufficient to indicate the difficulties and dangers to which its navigation is necessarily exposed. And to these difficulties and dangers, formidable enough in themselves, are often added the evil influences of preconceived theories and exaggerated expectations, usually followed by bitter disillusions. The calm judgment, which, to all the bold plans of navigation within the Polar basin, opposes distrust in their feasibility, while it points to the hundred expeditions which have at last returned home after penetrating but a little way into the frozen sea, is an attainment of slow growth. Years, too, must be devoted to the theoretical study of the Polar question, to the examination of all that predecessors have experienced and recorded. But this study is very important to Polar navigators; for the discoveries which they too readily regard as exclusively their own prove sometimes to have been made centuries before them.

2. A most essential element of success is the choice of a favourable ice year; and the commander of an expedition must possess sufficient self-control to return, as soon as he becomes convinced of the existence of conditions unfavourable for navigation. It is better to repeat the same attempt on a second or even a third summer, than with conscious impotence to fight against the supremacy of the ice.

3. Polar navigators have learnt in the school of experience to distinguish between navigation in the frozen seas remote from the land, and navigation in the so called coast-waters. The former is far more dangerous, entirely dependent on accident, exposed to grave catastrophes, and without any definite goal. It affords no certainty of finding a winter harbour for the long period when cold and darkness render navigation impossible. On the other hand, a strip of open water, which retreats before the growth of the land-ice only in winter, forms itself along coasts, and especially under the lee of those exposed to marine currents running parallel to them; and this coast-water does not arise from the thawing of the ice through the greater heat of the land, but from the land being an immovable barrier against wind, and therefore against ice-currents. The inconstancy of the wind, however, may baffle all the calculations of navigation; for coast-water, open as far as the eye can reach, may be filled with ice in a short time by a change of the wind. Land-ice often remains on the coasts even during summer, and in this case there is nothing to be done but to find the open navigable waters between the extreme edge of the fast-ice and the drift-ice. Should the drift become pack-ice, the moment must be awaited when winds setting in from the land carry off the masses of ice blocking the navigation, and open a passage free from ice, or at least only partially covered with drift-ice. It is evident that navigation in coast-waters must be slow and gradual, though it has always been attended with the greatest advantages. Barentz was the first who tested its value; but it was Parry, the most distinguished of all Polar navigators, who discovered its full importance, and from his day it has been accepted as an incontrovertible canon of ice-navigation. On this point he himself says: “Our experience, I think, has clearly shown, that the navigation of the Polar Seas can never be performed with any degree of certainty without a continuity of land. It was only by watching the openings between the ice and the shore that our late progress to the westward was effected; and had the land continued in the desired direction, there can be no question that we should have continued to advance, however slowly, towards the completion of our enterprise.”[5]

4. The successes of the English in the North American Archipelago were the result of this mode of navigation. Its principle is to search for and sail along the network of narrow channels when the main passage is blocked by pack-ice, and to turn to account the narrowest opening between the ice and the land. In the Siberian coast expeditions also this method of constantly following the coast-waters has been successfully observed. Where coast-water does not exist, or only to a limited extent, as on the East Coast of Greenland, this method is of course impracticable. The fate of the second German North Pole expedition is an illustration of this; it was ordered to penetrate in this direction, and its failure was inevitable. On the other hand, all the unsuccessful attempts of expeditions to penetrate northward from Spitzbergen—expeditions whose course and termination resemble each other as one egg resembles another—may be reckoned among those in seas remote from land. To the same category belong the expeditions for the discovery of a north-east passage, and simply because of the great extent of frozen sea between Novaya Zemlya and Cape Tcheljuskin.

5. In the frozen sea remote from the land, from 200 to 300, or at the most 400, nautical miles must, according to all past experience, be regarded as the greatest distance which a vessel is able to compass, under the most favourable conditions, during the few weeks of summer in which navigation is possible. The fact that Sir James Ross at the South Pole, and Norwegian fishermen in the Sea of Kara, accomplished still greater distances, only proves that they were little or not at all impeded by ice. Ross observed that the ice-floes of the Southern Arctic Seas are smaller than those of the Northern: “The cause of this is explained by the circumstance of the ice of the southern regions being so much more exposed to violent agitations of the ocean, whereas the northern sea is one of comparative tranquillity.”[6] The rarer occurrence of land at the South Pole permits freer scope to the currents of the sea, diminishes the opportunity for the growth of ice on the coasts, tends to widen the passages in the network of water-ways, and thus facilitates navigation. Even the swell of the sea within the ice is observed in the South Polar Ocean, while it is never seen in the North. Besides the greater hindrances peculiar to the whole North Polar Sea, there is the specially unfavourable circumstance, in the case of the North-East passage, that the shallowness of the Siberian Sea prevents a close navigation of its coasts.

6. The choice of the most appropriate season is another important consideration in ice-navigation; for this period does not fall at the same time in all seas, and the disregard of season was a common cause of the failures of the expeditions of earlier centuries. Since the frozen sea remains unbroken and almost unaffected by the action of the sun even in June, and at that time extends far to the south, it is evident that all attempts to force a passage in that month are labour thrown away. The ice-barrier retreating northward, or the transformation of pack into drift-ice, leaves free navigable water four or five weeks later. The month of August is the best time for ice-navigation in Baffin’s Bay; the end of July or beginning of August on the East Greenland coasts; the second half of August and the beginning of September in the Spitzbergen waters; and in the region of the Parry Islands the favourable opportunity ends about the beginning of September. In general, it seems that the time most propitious for all the coast-water routes, begins some weeks earlier than the corresponding period in the frozen seas remote from land. But since, even in the first weeks of September, the most promising conditions are often succeeded by a sudden reaction due to storms, to cold setting in rapidly, or to excessive falls of snow, navigation in the land-remote frozen seas, in itself so extremely hazardous, becomes specially critical, just when the ice-sheet at its minimum appears to promise the greatest results.

7. The help of steam power is an indispensable requisite, as by it a vessel is able to defy the capricious changes of the wind. The movements of a ship amid the ice are made in interminable curves, and the power to describe an arc with the least radius enables a vessel to follow up narrow and often blocked water-ways. As it is incessantly exposed to severe shocks from the ice, a paddle-wheel steamer is useless; and even in screw-steamers care must be taken to protect the propeller by a special construction.

8. The rate of speed of a vessel in the ice must necessarily be moderate. From three to six miles an hour are sufficient: and a rate of eight or ten miles would soon render her not seaworthy. But even with this reduced rate, her whole frame-work is shaken and loosened at last by the incessant shocks she sustains; and this condition of the ship becomes apparent when concussion with the ice is followed not by a noise as of thunder, but by a low, dull, groaning sound. The larger a vessel, the less her capacity to withstand these shocks, and the sooner will these signs of her diminished strength betray themselves.

9. An Arctic ship should be built with sharp rather than with full lines, so that when pressed by the ice, she may more easily escape being nipped and crushed. A ship built with what is called—in England—full lines, a full, round ship, is not easily raised but is liable to be crushed by ice-pressure. The Hansa was built in this manner, and was crushed by the first squeeze from the ice; the Germania and the Tegetthoff were both of them sharp-built ships, and stood the test of the ice excellently well. To protect it from the effects of grinding on ragged “ice-tongues,” the hull is generally iron-plated for some feet under water, and the bows are strengthened as much as possible, because this part of the ship is exposed to the greatest shocks.

10. The tactics of a ship in the ice are guided entirely by the character of the hindrances to be overcome. If the ice-fields be large and heavy, they are then generally separated by broader water-ways and “leads,” and a ship may often amid such ice follow her course for hours with few deviations subject always to the danger of being “beset” and crushed. When the passage is blocked by a barrier of ice, the situation becomes grave and serious; for such fields are not to be displaced by any force which the ship may exert, and nothing is left to the navigator but to await their parting asunder in a position as sheltered as possible. When the ice is loose and the floes comparatively small, the impeding barriers may be charged by the ship. She may then force asunder some of these floes or separate them by the continuous pressure of steam-power. In cases of this kind, large vessels have the advantage, and can bring to bear a greater amount of pressure, whereas smaller ones stick fast and remain immovable. These accumulations of ice, while they make a “besetment” more likely, diminish the danger of pressure.

11. Hence it is clear that small are to be preferred to large vessels for ice-navigation, except under circumstances of rare occurrence; first, because they are more readily handled, and next, because of their greater power of resistance and of their being more easily raised under pressure from the ice. Their one disadvantage of lesser momentum is of comparatively slight consequence. The experience of all the North Pole expeditions of this century shows, that ships of 150, or at the most of 300 tons, are best suited for all purposes.

12. Iron ships have often been employed, but with no success; they are far less able to bear pressure than wooden ships, as was proved, among other things, by the fate of the River Tay in 1868, in Baffin’s Bay, and of the Sophia, a Swedish ship of discovery in the north of Spitzbergen.

13. It admits of no question, that two vessels should be employed in preference to one, and this should be accepted as a first principle whenever the means at our disposal admit of it. Both ships should also be provided with steam-power, for otherwise their separation is almost inevitable—a danger, however, for which, under all circumstances, they must be prepared.

14. All that is commonly understood about piercing the ice by sawing and boring through it is a delusion, and arises from the misunderstanding of technical expressions. Where there is navigable water, there any one can sail—where there is none, no one. In 1869 and 1870, after coming on a cul-de-sac of ice in Greenland to the east of Shannon Island, we could not penetrate a yard further; in 1871, in loose, but solid ice, we drew away only by warping on the smaller floes, without being able to make the slightest progress, and in 1872 we were twice “beset,” in heavy ice, in spite of our steam power. The penetration of close pack-ice is an impossibility: in this case patient endurance is alone of any avail, and hence Sir John Ross so emphatically recommends the Polar navigator “never to lose sight of the two words caution and patience.”[7] If a vessel, therefore, is arrested by impenetrable masses barring its way, the breaking up of the ice must be patiently awaited, and this, generally, is effected by calms, although the ebb and flow of the tide appear to have an influence on the solidity of the ice. It is then usual with sailing ships to seek the larger “ice-holes,” or keep in the freest water-ways, in order to guard against the danger of being completely inclosed. These precautions, however, are not so requisite for steam-vessels, as their power to escape quickly and in any direction secures them against this danger. A steam-vessel may even venture to fasten on to an ice-floe by means of an ice-anchor, and of course under its lee, the fires being banked up, so that by getting up steam she may shift her place as soon as the ice moves nearer. As a principle, and so far as it is possible without the exhaustion of her powers, a ship in the ice should endeavour to be in constant motion, even though this entail many changes of her course and the temporary return to a position which had been abandoned. The making fast to a floe, however, should never be attempted, except when every hope of navigating in the surrounding waters has been proved fruitless. The fastening a vessel to an iceberg diminishes, indeed, its drifting, but is, if possible, to be avoided, because of the danger of the iceberg overturning or rending asunder, things which occur far more frequently than we should be led to expect from their great appearance of stability. When a ship, notwithstanding every possible caution, is “beset,” it is then advisable to “ship” the rudder in order to protect it from injury, to which it is peculiarly liable from its unusual weight and size. A ship is exposed to considerable danger when she finds herself among icebergs in a calm; but since these are over-spread by a dazzling sheen, even in the thickest mist, the peril of the position is to be avoided at the last moment by warping.

15. As the happy choice of a sea-way is one of the essential conditions of success in ice-navigation, the ability to determine the ship’s position and to ascertain whether a surface covered with ice to the horizon, admits of being penetrated, is most desirable. Hence the employment of a balloon would be of the last importance in Arctic navigation. The advantage of being able to ascend from the ship in a balloon secured by a rope, to the height of a few hundred feet, is self-evident; and, undoubtedly, the first vessel which avails herself of this great resource will derive extraordinary benefit from it.

16. From the deck of a ship even drift-ice appears to be of such solidity at a little distance as to defy navigation, while from the mast-head more water than ice may be descried. In order then to extend the horizon, a look-out, called “the crow’s nest,” is fixed on the mast-head, in which an officer is always on the watch, and from which all the operations of the vessel are directed. In a ship of the size and height of the Tegetthoff the horizon visible from “the crow’s nest” extends to about eleven miles,[8] but at the distance of even five miles the possibility of penetrating cannot be determined with sufficient exactness. It is the business of the officer in “the crow’s nest” to observe the passages through the ice and distant objects generally, as he is in the best position to fulfil this most important duty. It is the special business of the watch on the forecastle to mark what lies in the immediate neighbourhood of the vessel, and his constant care is demanded to avoid isolated ice-floes and prevent collision with them. The seaman at the helm steers the ship by the signs and calls which come to him from “the crow’s nest,” and modifies them according to those of the watch on the forecastle. The rest of the crew remove the smaller fragments of ice from the vessel’s course, special care being taken to prevent their damaging the screw.

17. While sea-currents move the ice in close and continuous lines, winds produce great disturbances in their movement, and open long “leads” in the direction of their course, which often alternate with strips of the thickest pack-ice. This movement of the ice varies with each accumulation of floes, as its rate of motion depends on the height of the ice-field, which then acts as a sail. It is ascertained by experience that calms, on the other hand, have the remarkable property of breaking up the ice. The knowledge and application of these circumstances are essential to the Arctic navigator. If the course of a ship lies across or against a current, it is constantly deflected. The deflection on the coast of East Greenland, for example, amounted to five, even ten miles, within twenty-four hours; hence the importance of choosing routes with and not against the course of currents.

18. Lastly, it is of the greatest moment to choose betimes an appropriate winter harbour, and it is therefore necessary to keep near the coast towards the close of the season for navigation. To find one suitable for shelter during the winter in an unknown Arctic region is a matter of great difficulty, for it very often happens, that the ice drifts out from these “docks”[9] in the storms which constantly occur, or perhaps the “dock” is so sheltered, that the ice, if it breaks up at all, breaks up only in the following summer. Shallow bays which freeze almost to the bottom, lying under the lee of a current or within a fiord, are the most appropriate spots in which to winter.