Submarines in the Polar Sea

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EA-Oceanography

(H. U. Sverdrup)

SUBMARINE S IN THE POLAR SEA

       

History

        It is remarkable that the idea of using a submarine for arctic explora–

tion was advanced about 250 years before the first submarine was designed.

In 1648, the Rev. John Wilkins proposed “framing an ark for submarine naviga–

tion,” pointing out among its advantages that such a craft would be safe

“from ice and great frosts, which do so such endanger the passages towards

the Poles.”

        After submarines had been designed, the inventor, Simon Lake, was

probably the first to advocate its use in the Arctic. On April 4, 1898,

Mr. Lake applied for United States patent of a submarine vessel that was

especially designed for travel under the ice. But thirty-three years passed

before Sir Hubert Wilkins, in 1931, tried to put the idea to a practical test.

Wilkins, who in 1913 to 1916 took part in Vilhjalmur Stefansson’s arctic ex–

pedition, tells that Stefansson first drew his attention to the possibilities

that a submarine offers for arctic exploration, but years passed before he

could think of following the matter up.

        The opportunity came in 1930, when Wilkins succeeded in obtaining the

free loan of a United States submarie, the 012 which, according to the naval

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agreement of 1922, was to be scrapped. The 012, which had been built in 1917,

was removed from the Navy Yard in Philadelphia, converted, and renamed the

Nautilus .

        After a number of delays due to various mechanical difficulties, the

Nautilus reached Advent Bay, Spitsbergen, on August 15, 1931. A week later,

on August 22, the first ice was encountered to the north of Spitsbergen, and

the Nautilus got ready to down beneath ice for the first time. When preparing

to dive it was found, however, that the diving rudder had been lost, so that

the “Nautilus” was useless as a submarine. During the next two weeks the

Nautilus operated as a surface vessel, reaching latitude 82° N. because of

unusually favorable ice conditions, but no experience as to the use of a sub–

marine for arctic exploration was gained.

        From 1931 to 1949, no new attempt was made to explore the Polar Sea by

submarine. Thanks to enormous technical improvements, a 1949 submarine should

be so far superior to the older types that navigation of the Polar Sea should

not now entail any great risks. These risks are commonly exaggerated, as

will be shown in the next section.

       

Possibilities for Use of a Submarine

        The following objections are generally raised against the use of a sub–

marine for exploration of the Polar Sea.

1. The Polar Sea is covered by compact ice, making it impossible for
   
   a submarine to surface.
   
   
2. Even if there are openings, the submarine cannot find them.
   
   
3. Navigation under the ice is impossible.
   
   


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4. The ice cover is too thick for a submarine to advance underneath it.
   
   
5. Icebergs present a great hazard.
   
   
6. Unknown shoals may prove disastrous.
   
   

        The first objection is correct so far as winter conditions are concerned,

but does not apply during the two to two and a half months in summer when the

air temperature over the entire Polar Sea remains at freezing point or a lit–

tle above. During this period excessive melting of the sea ice takes place

and lanes that open up do not freeze over. Furthermore, when the ice moves

apart, it generally breaks along a ragged line, and the ice fields move not

only directly away free each other, but, also sidewise. When, later on, the

ice is again compressed, the sawtteth do not fit, but corner meets corner,

leaving large open areas in between. Both the melting and the discharge of

ice by the East Greenland Current contribute toward reducing; the total ice

cover of the Polar Sea so much that in August the spaces of open water way

amount to 5% to 10% of the total area. All arctic travelers who are familiar

with the appearance of the polar ice in summer agree that numerous openings

exist, and that no region has been visited as yet where one could advance as

much as 10 miles on a straight line without striking an opening large enough

for a good-sized submarine to surface in. Aerial photographs confirm this.

        Thus, in summer the character of the ice cover does not prevent the use

of a submarine which depends upon being able to surface at relatively short

intervals in order to charge batteries. In winter a submarine may be able

to drill a hole through the ice, using mechanical means or heat, and get air

through the hole; or the submarines of the future may be able to go submerged

across the Polar Sea.

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        The second objection, that a submarine could not find such openings as

exist, is not valid in any circumstances. In summer the openings can be seen,

and in all seasons one can use an inverted echo sounder which records the

distance to the under side of the ice and which, combined with the depth gauge

of the submarine, gives the thickness of the ice.

        The third objection, that navigating beneath ice is impossible, is some–

what more serious as far as navigation in the vicinity of the North Pole is

concerned, because the gyrocompass fails at the Pole, although it can be used

beyond [ ?] 82° N. A magnetic compass cannot be used inside a steel hull, but

it may be possible to place it in a specially designed blister.

        The fourth objection, that the ice cover of the Arctic Sea in too thick,

is not valid. The average thickness of relatively level ice floes is in summer

not more than about 3 meters (10 feet), but the ice that is accumulated below

pressure ridges may extend to a depth of 20 meters (65 feet), and in deep

near-shore areas to twice that depth. The temperature and salinity conditions

within the known part of the Arctic Sea indicate, however, that there the ice

extends nowhere below a depth of 30 to 40 m. because below these depths the

temperature of the water has always been found to be above freezing point,

meaning that no ice is reaching down into that water. A submarine traveling

at a depth of 50 meters should be in so danger of running into any ice, and

even at a depth of 30 m. the risk should be extremely small.

        The fifth objection, about icebergs, is of no particular consequence, for

only a few small bergs occur, and only in the marginal areas of the Polar Sea

off northern Svalbard, Franz Josef Land, and Northern Land ( S Severnaya Zemlya);

and these bergs, as well as deep accumulations of ice below pressure ridges,

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can be discovered at some distance by sonic scanning devices.

        The sixth objection, that the submarine might run into a shoal, is even

less important; for every submarine can be equipped with a sonic depth re–

corder, the indications of which will give ample warning if the depth to

the bottom should decrease so much that one say suspect the presence of

shoals.

        Actually the oceanographic conditions in the Polar Sea in summer repre–

sent advantages to a submarine. At a depth of 30 to 40 meters the density

of the water increase fairly rapidly with depth, making it possible to trim

the submarine effectively. The variations with depth of temperature and

salinity is, on the other hand, not rapid enough to reduce the horizontal

range of echo-ranging equipment.

        The depths to the bottom combined with the thickness of the ice will,

however, introduce great hazards to the use of a submarine in one special

locality, the shallow continental shelf off eastern Siberia,. Below very

large pressure ridges the ice may reach to a depth of 20 meters below the

sea surface, meaning that a large submarine can hardly advance safely when

the depth to the bottom is less than 40 m. This implies that a submarine

may have difficulties in reaching the deep parts of the Polar Sea from Bering

Strait and will be of no use in the East Siberian Sea. It can, on the other

hand, safely enter the Polar Sea between Spitsbergen and Greenland and can

leave by the same route.

        The possibilities for oceanographic exploration of the Arctic Sea by

submarine are nearly unlimited. During two to two and a half months the

submarine can move freely in any direction, it can obtain exact depth profiles

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along every route it selects, it can occupy a large number of oceanographic

“stations” at which measurements of the temperature can be made at any depth,

and water samples can be brought up for chemical analyses. Net hauls can

be completed for collection of biological specimens, bottom samples can be

obtained, and so on. In addition, when the submarine is in surface posi–

tion, meteorological observations by means of radiosondes can be conducted

and magnetic measurements and measurements of gravity can be undertaken.

        The investigations that can be made are so numerous and varied that the

exploration of the Polar Sea by submarine is one of the most attractive and

fascinating tasks which recent technical development has brought within reach.