Ar′mor, sub-ma-rine.
Submarine armor may be held to include all the devices to be attached to the person by which one is enabled to descend in the water, be protected from extreme pressure while submerged, be furnished with vital air and with means for signaling the persons above and for assisting the ascent to the surface when necessary.
These devices have been used in connection with the diving-bells, but the latter is not a necessary auxiliary.
In the article on the diving-bell some instances of submarine armor are given, but only as incidentals.
Submarine armor has not as clear claims to antiquity as the diving-bell, if we accept the accounts of Aristotle and Jerome.
The earliest distinct account of the diving-bell in
Europe is probably that of
John Taisnier, quoted in
Schott's
Technica Curiosa,
Nuremberg, 1664, and giving a history of the descent of two Greeks in a diving-bell, “in a very large kettle, suspended by rope, mouth downward” ; which was in 1538, at
Toledo, in Spain, and in the presence of the Emperor Charles V.
Beckman cites a print in editions of
Vegetius on War, dated in 1511 and 1532, in which the diver is represented in a cap, from which rises a long leather pipe, terminating in an opening which floats above the surface of the water.
Dr. Halley, about 1717, made a number of improvements in the diving-bell, and among them a leather cap for the head of the diver, with windows in front for the eyes.
This helmet was used by the diver when he left the bell, from which he received a supply of air through a flexible tube.
The essential parts of submarine armor consist of a helmet and a protection for the body.
These are rendered necessary by the great pressure of the water even at moderate depths.
For instance, at a depth little exceeding five fathoms (30 feet), this pressure amounts, including that of the superincumbent atmosphere, to about 29 pounds to the square inch, being an excess of some 14.7 pounds over that due to the atmosphere alone.
For depths not exceeding 15 or 20 feet, armor for the body is not perhaps absolutely essential, though very desirable if the diver is required to remain a considerable time under water; this part of the apparatus may be constructed of leather, vulcanized rubber, or gutta percha, or of metal.
The helmet is almost necessarily made of metal.
It has glass windows to enable the diver to see, and two tubes,—one for supplying him with fresh atmospheric air from the surface, and the other for the eduction of the exhaled air. Weights are attached to the body of the diver or to the armor, if the latter is not sufficiently heavy of itself, to enable him to exert his full power under water; the human body being very nearly of the same specific gravity as that fluid.
A line is attached to the apparatus, by which the operator is lowered to any given depth, or hauled to the surface by the assistants, and by which he can signal to them when necessary; for this purpose, however, another line is usually employed.
Many different constructions have been proposed and executed.
One of the best of the earlier forms was that of
M. Klingert of
Breslau, 1798, in which the helmet was made of strong tin, and the jacket and drawers of leather.
Inhalation was made through a tube embraced by the lips of the diver, who, by the expansion of his chest at each inspiration, forced out of the helmet into another tube leading to the surface a quantity of previously exhaled air precisely equal to the fresh
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air taken into the lungs.
In some of the older forms the helmet itself was made large enough to hold a quantity of air sufficient to supply the diver for a considerable length of time, differing little, in fact, from the diving-bell.
The apparatus of
Mr. Rowe, 1753, consisted essentially of a copper tube large enough to contain the body of the diver and a limited supply of air which could be renewed from time to time by a bellows or force-pump, and having windows and water-tight holes for the arms.
These cases have, however, been completely superseded by the divingbell, and it by the more modern forms of armor, some of which will be mentioned.
See diving.
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Dixing apparatus. |
Fig. 359 shows a figure in a diving-dress, attached to which is a reservoir of compressed air sufficient to last the diver several hours.
It is strapped to the dress, and communicates with the interior of the latter by a pipe which has a faucet.
Expansible bags are attached to the shoulders, which are made buoyant by inflation from the compressed-air reservoir when required.
The air-knapsack is weighted so as to enable the diver to sink to his work.
The air-tube enters the mask at a point over the ear. The artist has made rather a close fit of the dress and mask, and the effect is rather too cherubic.
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Hawkins's mouthpiece for diving apparatus. |
In
Fig. 360 is shown a respirator designed to be attached to the helmet of the diver whereby air is supplied from a forcepump in the vessel which floats on the surface of the water.
It has an induction and an eduction valve, which both open in the same direction, giving way respectively to the blast of fresh air and to the force of the exhaled breath.
While the breath is being inspired by the diver the induction-valve is open to admit fresh air, and when expiration occurs, the induction-valve is closed, and the air passes out by the eduction-valve and the flexible tube, which latter reaches to the surface of the water.
In
Fig. 361 the diver is completely incased in the armor, which has flexible jointed limbs occupied by the legs and arms of the occupant, and enabling him to move from place to place and grasp the objects of his search or perform his other duty in the premises.
The joints of the limb-casings have articulations corresponding to those of the person, and are flexed and extended by the natural motions of the diver.
The prosthetic hands, which are attached to the ends of the tubular arm-casings, consist of tongs or nippers, operated by rods, which are moved by the natural hands inside.
The body and head of the person occupy the chamber, which is large enough to permit free motion, and the chamber is attached to the person by bands, and a girdle about the loins.
An exterior reservoir, partially encircling the chamber, contains compressed air, which is admitted to the chamber by a faucet, as the air may become vitiated by breathing.
The opening of another faucet permits the vitiated air to escape through the tube which leads to the surface of the water.
If the
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operator wish to ascend without assistance, he turns another faucet, which permits air to pass from the chamber into a collapsed bag attached to the top of the apparatus.
As the bag becomes inflated, it displaces water and renders the whole apparatus buoyant.
To descend again, he closes the cock leading to the balloon, and opens another which allows the air to escape from the balloon, which is collapsed by the pressure of the water.
The compressed air is intended to form a supply for the trip, the connection with the surface consisting of a lifting and lowering rope and the eduction air-pipe.
Other armor for submarine explorations consists merely of helmets which have the necessary windows to allow the diver to see his work, and are provided with induction and eduction tubes to furnish the operator with a supply of vital air and carry off that which is vitiated.
Some exploring apparatus are adapted for making observations without descending.
These consist of tubes, telescopic or otherwise, the lower end being brought into near proximity to the object; and in one case—Knight's English Patent, about 1847—a second tube was provided, down which was projected light from a lamp or the reflected light of the sun, so as to illuminate the object whose character or position it was desired to ascertain.
In 1839, Thornthwaite (
England) adopted a waist-belt of india-rubber cloth, to which was connected a small, strong copper vessel charged with highly compressed air. The belt is put on in a collapsed state, and the diver descends; but when he wishes to rise, by a valve he allows the compressed air to fill the belt, which increases his levity and assists his ascent.
The armor used by
Mr. Dean in 1834, when he descended to the wreck of the
Royal George (sunk off
Spithead, August 28, 1782), was composed of india-rubber, made perfectly water-tight, and having a metallic helmet which rested on the shoulders and admitted free motion of the head.
Three glass windows admitted light and allowed the diver to examine the remains of the ship.
A flexible tube was connected to an air-pump above, and admitted air to the helmet.
A sinking-weight of 90 pounds was attached to his person.
A race in submarine armor took place in
Boston harbor on the 4th of July, 1868.
The course was 2,100 feet, reaching from Long Wharf to the
Cunard Docks on the East Boston side.
Each diver had a submerged direction-line, and each arrived safely, being accompanied by his boat with its usual air-pump rigging.
The time made was 17, 18 1/2, and 21 minutes respectively.
Each received a prize.
