US2342194A - Torpedo shield for ships - Google Patents

Description

'2 Sheets-Sheet 1 INVENToR.

ATTORNEYS.

Feb. 22, 1944. .J. 4. HARDY TORPEDO SHIELD FOR SHIPS Filed April 17, 1942 lH/vCw@0.5225471490 Feb. 22, 1944. J. c. HARDY TORPEDO SHIELD FOR SHIPS 2 Sheets-Sheet 2 Filed April .17, 1942 mm wm IN V EN TOR.

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Patented Feb. 22, 1944 UNITED STATES YPATENT OFFICE TORPEB() SHIELD TEUR YSHIPS John Cyrus Hardy, North Hollywood, Calif."

Application April 17, 1942, Serial No. L139,303

2 Claims.

My invention relates lto the protection vof `all types of ships against torpedo attack and particularly to a `floating shield vadapted `to be `towed :alongside of a ship 'to activate a torpedo firing pin for exploding the charge at a harmless distance from the ship.

I-am aware of attempts to protect warships by the use of so-called blisters attached to the hull, but these have the disadvantage of adding weight and substantial drag to the ship as Well `as 1permitting the torpedo to explode close to the hu l.

It is an object of my Ainvention to provide a torpedo shield for ships which may be towed either by the ship it is designed to protect or by a tugboat, which is of relatively light weight and offers a minimumof resistance to towing, which has the requisite buoyancy to float, preferably below the surface, and which is made and assembled in units, sections or plates which are readily replaceable at sea, and which will cause a torpedo to explode and expend itself at a safe distance from the ship.

More specifically I have discovered that torpedoes may be made to yexpend themselves against a submerged unobservable shield of plastic -or plastic impregnated plywood Iplate carried or towed vertically under the surface of the water by coupled sections of cable or chain flexible at the coupling. Plastic impregnated plywood being relatively thin, light and water resistant, backed by the incompressibility of water, is easily sufficient to activate a torpedo firing pin which strikes a percussion-detonator, and explodes the charge at a completely harmless distance from the ship. By the use of my invention the shield of plastic plates coupled together may be conveniently carried at a distance of 2.0 to 4.0 feet from the side of the ship, according to the size of the ship and the corresponding most suitable distance, and thus render a torpedo almost totally ineffective. While I have found plywoo'd most suitable, as well as economical, it is obvious that other materials having the requisite characteristics may be employed.

These and other objects of my invention will become more apparent from the detailed description thereof which follows.

In the drawings:

Figure 1 is a top plan view of a ship equipped with my torpedo shield.

Figure 2 is a side horizontal View of the same, with water in section.

Figure 3 is an enlarged side elevation of a plurality of units or sections comprising my shield.

.Figure 4 `is a top plan 'view pf the .leading plate and .its coupling with the next adjacent plate.

Figure 5 is a vertical sectional view taken Lon the line i5-5 :of Figure 3.

.Ihaveillustrated any conventional ship Ir provided with forward booms II and stern booms 1.2 -of -suiiicient ,length to x the position of shield i3 preferably at about 25 feet from either side of the iship. This distance, however, is variable. The vforward :or towing booms should be guyed for lstrengthin supporting the t0W,.in any well known manner. The stern boom may-be omitted in favor of simply a guyed line without a boom. The propeller Wash of the rship will :tend to hold the shield `away from the :ship the ,properdistanca The shield `I3 comprises one but preferably a plurality `of lplates M which may for example be made of one-half inch plastic impregnated plywood, or any other relatively light, thin water resistant material. Any kind of wood is adequate, but is preferably Atreated in a manner to prevent .it from becoming Water soaked and deteriorating in use. Various methods of preparing the wood are well known. Y

In order to maintain the plates in a vertical ,position -in the water necessary to offset their specific gravity tendency to float to a horizontal position, I employ relatively thin metal keels` l5 which may be attached to the lower edge of the plates 4:4 in vany suitable manner, as for example shown in Figure 5 where the keels are inserted in central grooves lli and held fast by bolts or rivets l1. The lower adjacent corners Lof the keels I5 are coupled by chains I8, having a removable link; snap or hook indicated at |811. The weight of the keels l5 and the chains I8 in relation to the volume and weight of the plates I4 together with the other attaching parts hereinafter described is preferably such that the plates are floated in a vertical position slightly under the surface of the Water. There are vtwo primary reasons for the latter: The shield is rendered invisible, and added protective depth is afforded without sacrifice of protection at the surface, for torpedoes are commonly designed to charge submerged.

The leading shield is coupled to the ship for towing by a guide cable 2B (preferably steel) at-` tached to the lower part of the shield, and a tow line preferably of hemp 2l having surface buoyancyconnected through the forward boom Il to the ship. The bottom guide cable is designed to maintain the vertical position of the shield when the ship and shield are making a sharp turn.

It should also be noted that the leading shield is preferably beveled as at 22 to streamline the device. It is also provided with a horizontal type of rudder or stabilizer 1in 23 having its nose 24 lower than its tail 25 and also being adjustable to vary the angle of attack, as for example by means of slots 26 through which bolts 21 secure the rudder n upon the plate I4. The rudder n need ordinarily be adjusted a few degrees off horizontal, and loperates much in the manner of a paravane. An actual paravane might be substituted providing an automatic depth regulating rudder.

The upper edges of the plates I4 are coupled togetherin any suitablemanner, as for example by buoyant hemp lines 28, the leading one of which attaches to the tow line 2 I; and such lines 28 may be secured to the upper edges of the plates by any suitable form of clamps 30, and are preferably provided with snap couples 28a for quick attachment. Or the coupling may be by chain links', as illustrated at the lower corners of the plates.

The spacing between adjacent edges of the vplates is such as to allow flexibilityboth horizontally and vertically to accommodate rising and'falling water currents as well as lateral displacement, as for example when the ship is turning; In order to maintain the line of shields at the same approximate normal level it may be desirable to reduce the weight of the keels on the intermediate plates to compensate for any lifting effect upon the forward and rear end plates arising from the towing line connections.

On the trailing edge of each plate I bolt, rivet or otherwise attach at each side a coupling guide plate 3l which may be iiared outwardly to a slight degree, and which overlaps the leading edge of the next adjacent plate. These guide plates 3| perform the functions of reducing turbulence and dragat the joints, and effect a substantially solid shield over the most critical area of the plate junctions. These guide plates may, of course, extend the full depth of the shield if desired. The flaring of the guide plates streamlines the movement of the shield as a whole and at the same time permits slight relative horizontal shifting of the shields.

Even'relatively light plates of the character described, backed by the incompressibility of the water, are sufficient to activate a torpedo ring pin, and the effect of an explosion is to destroy individual plates or shields, possibly not more than one, two, or three. As has been explained, these are designed to be readily replaceable by a boom lift. It may be advantageous to turn the ship about, presenting the shield on the other side toward the attacking submarine, While the damaged or destroyed sections are being replaced, an operation calculated to be possible in an hours time, causing no delay in the ships progress. The sections may be replaced with the ship under way. In experiments it has been found that plastic plywood at a suggested thickness of one-half to one inch with beveled cleavage and drag points as described, creates a negligible friction and the towing strain is not excessive from either an engineering nor a power viewpoint. The calculated weight of port and starboard shields for a 10,000 ton ship is about two and a half tons, largely sustained by its own buoyancy.

Although I have herein shown and described my invention in what I have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of my invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent structures.

Having described my invention, what I claim as new and desire to secure by Letters Patent ist 1. A protective device forships comprising a shield adapted to be towed alongside a ship and having buoyancy and suicient keel weight to cause it to float in a vertical position and presenting a relatively iiat thin and rigid wall to actuate the firing pin of a torpedo when struck, said shield comprising a plurality of sections loosely coupled end to end, and guide plates attached to the trailing edge of each section substantially covering the space between sections and loosely overlapping the leading edge of the adjacent section with a slight outward flare;

2. A protective device for ships comprising a shield adapted to be towed alongside a ship and having buoyancy and suicient keel weight to cause it to float in a vertical position and presenting a relatively flat thin and rigid wall to actuate the ring pin of a torpedowhen struck, said shield comprising a plurality of readily replaceable sections loosely coupled end to end, each-section comprising a thin plate of plastic impregnated plywood, and a thin metal keel atv tached thereto and said keel being of substantial depth to increase the eiective area of said section,

JOHN CYRUS HARDY.

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