US38106A - Improvement in submarine harbor-defenses - Google Patents

Description

UNITED STATES PATENT OFFICE.

JOHN S. GILBERT, OF NEW YORK, N. Y.

IMPROVEMENT IN SU BMARINE HARBOR-DEFENSES.

To all whom t may concern:

Beit known that I, J onN S. GILBERT, of New York, in the county and State of New York, have invented a new and useful Improvement in Harbor-Defense, which I term a Balance Submarine Harbor-Defense g and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawin gs, makin ga part of this specification, and to the letters of reference marked thereon.

The object of my invention is to obstruct the entrance of a harbor to the passage ofthe ships of an enemy. This has hitherto been essayed by means of sunken wrecks, which have been exceedingly objectionable on account of the obstruction they also offer to the passage of the water7 which is certain to result in the formation of shoals and bars and a change of the channel, and ultimately in the destruction ofthe harbor. They are also difficult and expensive to remove when no longer required, and it has frequently happened that all attempts with the costly appliances of diving-bells and submarine blasting have been insuicient to accomplish this purpose. Chains stretched across the entrance have also been used, but it is necessary in wide spans to support them with buoys or floats that can easily be destroyed by shot projected from a distance, causing the chain to drop and leaving the entrance open. And chains of moderate length that are sufficiently strong to be strained in a line near the surface ofthe water and left unsupported offer but little resistance to the surge of a floating body propelled against it, on the same principle that the chain of a suspension-bridge is weakened in proportion to the iiatness of the arc of the catenary employed.

My invention consists of a series of open crib-work frames or sections raised on legs from the bottom to permit a free passage of the current, and supporting a system of chains which are stretched between them in such a manner that a vessel striking either against them or against the inclined ends of the frames will be deilected and clamped between the sections. Both the frames and the chains are teries.

fitted with iron tanks that are water and air tight, and of sufficient size and buoyancy to oat the entire structure when its removal maybe desired. When these tanks are filled with water, the weight of the material of which they are constructed ballasts the sections steadily in position.

The relative situation of the tanks and the center of gravity of the sections is established in such a manner that there isa constant balance or restoring power preserved between the forces of buoyancy and gravity when the sections are being raised by forcing the water from the tanks with air or by pumping the water from them and allowing air to supply its place. After the sections have been lifted a few feet to bring the chains to the surface, they may be detached and iioated separately away.

To enable others skilled in the art to which it appertains to make and use my invention, I will proceed to describe its construction and operation with reference to the drawings.

Figure l is a plan of a series of these frames or sections built and connected according to my said invention. VOnly three sections have been represented on the drawings, but as many of them may be used in a similar manner as may be required by the extent of the harbor it is desired to defend. Figs. 2 and 3 are respectively an end and a side eleva-tion of the same.

The crib-work frames or sections a are sup= ported on the legs b, which are built into the sides and extend to the top of the structures. The floor-beams c d e form spaces for the reception of the air-tight iron tanks f, which are represented on the drawings as occupying the lower tier, but which may be placed, it'desired, in the upper tier of spaces in adjusting their buoyancy to the ballasting of the sections. Where these sections are necessarily constructed of large size to accommodate them to a great depth of water, it is considered advisable to use tanks in both tiers, by which arrangement the lower ones will not only operate as ballast while filled with water and sub merged, but will furnish buoyant power for floating the sections when required. The outer ends of the frames are formed angularly and are properly braced. The sides are also furnished with diagonal braces for the reception of the angular strain which would be occa sioned by a vessel striking on the end and fare pointed at the ends to diminish their resistance to the water. They are provided with suitable valves and connections for the reception of machinery, carried by an attendant vessel fitted for the purpose, for pumping air orv water to discharge the water within them Y after any of the various methods known to engineers and mechanics. These frames or s ections may be constructed on shore and bolted and clamped together in the ordinary manner with screw and key bolts, which canbe readily removed when it is desired to store or house ihe parts during such time as they may not be required for the purposes of defense. They are made entirely of straight timber, involve no skilled labor in their construction, and can be built and placed in position under an emergency with great facility and quickness. Being supported on legs that may be strongly braced without oiler'ing any appreciable resistance to the Water, they are a sufticient distancev from the bottom to avoid any scouring of the channel. The chains are fixed at the The tanks can be removed for painting or repairs Without taking the sections apart, and they may be used as reservoirs for the'storage of water and other purposes in barracks when no longer required by the necessities of war for the office for which they were designed.

The crib-work may be of wood or iron, and may be ballasted, either in the tanks or other- .wise, withv stone, iron, or any other material that may be convenient. Torpedoes may also be used in combination with this system of obstruction in such'a manner that they will be exploded under a vessel by its collision with the chains or front ends of the sections.

It is preferable for the convenience of lifting and transportation tov make the sections in pairs; and it may be advantageouslto loop up the'outer chains connecting the' sections with shackles that are weaker than the links so that the shackles may be broken without breaking the chain, which will thus obtain sufficient scope to admit a vessel far enough to be resisted with the additional and comsbined force of the next pair of chains.

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