US2386950A - Means for protecting ships at sea - Google Patents

Description

Get. 16, 1945. N. M. HOPKINS 2,386,950

MEANS 'FOR-PROTECTING SHIPS AT SEA Filed Jan. 20, 1943 6 Sheets-Sheet l oct. 16, 1945. N, M HoPKlNg 2,386,950

MEANS FOR PROTECTING SHIPS AT SEA Filed Jan. 2o, '1945 e sheets-sheet 2 6 Sheets-Sheet 3 lq Q gwoon/bwa Oct. 16, N45.

N. M. HOPKINS MEANS FOR PROTECTING SHIPSl AT SEA Filed dan. 20, 1943 0d. 16, 1945. I N, M, HOPKlNs 2,386,950

MEANS FOR PROTECTING SHIPS AT SEA Filed Jan. 20, 1943 e sheets-sheet 4 MMHQPW Attorney Oct; 16, 1945.

N. M. HOPKINS MEANS FOR PROTECTING SHIPS AT SEA 6 Sheets-Sheet 5 Filed Jan. 20, 1943 oct, 16, 1945.

N. M. HOPKINS MEANS FOR PROTECTING .SHIPS AT SEA y Filed Jan. 20, 1943 6 Sheets-Sheet 6 Patented Oct. 16, 1945 sepia MEANS FOR PROTECTING SHIPS AT SEA Nevil Monroe Hopkins, New York, N. Y.; Raymonde B. Hopkins executor of said Nevl Monroe Hopkins, deceased Application January 20, 1943, Serial No. 473,010

19 Claims.

This invention pertains to new methods, ways and means of protecting the hulls of ships against submarine discharged, and plane launched torpedoes, and certain types of mines, the magnetic mine in particular, under all normal conditions of Wind and sea, this invention comprising not only the protection to a ship equipped against the magnetic mine, but also the protection to a ship following in its wake, by means of a magnetic loop towed astern.

It is an exceedingly important major object of this invention to provide deep torpedo protection and deep magnetic mine protection, through netor belt-like devices and equipment capable of navigating with the ship, well below the roots of waves, for several vitally important reasons-to yavoid being smashed by the forces of the Wind and seaiand to reach deeply moored magnetic mines and deeply launched magneticwarhead sh torpedoes, for example.

It is also an important object oi the invention to carry the protective belt equipment farther from the hull of the ship than heretofore possible with booms and paravanes, thereby giving protection against the most powerful supertorpedoes now in use or in the making.

It is also an object of the invention to provide Counter-magnetic mine electro-magnetic fields well in advance of a ship in times of gale, when radio controlled surface launches or aeroplanes electro-magnetically equipped could not operate.

It is also an important object of the invention to provide a barely floating electric towing sh" device and a barely iioating net or belt device when at rest in the water of the sea, both fashioned to be sent, by remote control from the protected ship, to one or more depths below the surface of the sea at Ia predetermined speed of navigation, through aquaplane means, capable of slowly stopping or turning aside a iish torpedo without exploding it, and therefore protecting the hull of a ship against one or more torpedoes launched successively, one behind the other.

It is also an important object of the invention to provide novel designs vof counter-balanced, motor operated winding drums for the cables of the power and wired radio control circuits, capable of insulating the cable, and yieldably paying out and anchoring the cable, respectively, and of controlling the .angle of leads of the cables with the sides of the ship, to control the pull of the electric fish by speeding up or retarding them. Therefore, there is contemplated the steering of the electric lish and the maintenance of belt position in the sea, as well as the depth and speed 55 control. of both, tension on the cables, and the provision for comparatively small angles of cable lead from ship to electric fish, in order to establish and maintain a minimum of lateral cable drag in the sea as well as to conserve useful deck space for cargo.

It is a further object of the invention to employ wired, or guided radio, some times called carrier current radio for the control of the "electric fish from the ship using the angular displacement of the winding drum carriages, as well as the power cables for the purpose.

I-t is also an object of the invention under certain conditions to employ the wired or guided radio for purposes of remote controlusing both the cables and the salt water of the sea as conductors for the carrier currents.

With the foregoing objects in view, as well as certain additional objects made possible by modern engineering methods, which will become apparent as the description proceeds and the draW- ings are studied, the invention resides in the novel and useful designs of apparatus and combinations of apparatus and equipment, as well as scientific principles all as hereinafter set forth and particularly covered by the claims.

Referring to the accompanying illustrations forming a part of this speoiiication and in which like numerals designate like parts in all the views:

Figure 1 represents in partial vertical longitudinal section and partial elevation, one design of my electric iish for comparatively quick manufacture using standard types of electric motors, for the towing of a submerged anti-torpedo belt for ships at sea, and/or an electrical conductor for establishing a magnetic field for exploding magnetic mines planted in the Sea.

Figure 2 is a side view of this electric iish in elevation.

Figure 3 is a partial horizontal longitudinal section and partial elevational top or plan View of this sh.

Figure 4 is a top plan view of a small cargo vessel under way, equipped with one design of my submerged electric fish, belt device, winding drums and other devices of the system for protection against torpedoes launched by aeroplane or discharged by submarine, with its possible auxiliary anti-magnetic mine feature.

Figure 5 is a side view of this cargo vessel underway, so equipped, indicating the sub-sea surface navigation at one possible selected depth, of the combined electric iish and protective belt.

Figure 6 is a side view in partial section design of one of my stanchion supported yieldable, motor operated winding drum for angular control of multiple cables, tension regulation, and the like in the water of the sea.

Figure 7 is a top plan view of this drum device in partial section.

Figure 8 is a top plan View of a small cargo vessel under way, equipped with an alternate design of my submerged electric sh, simplied cable and winding drums therefor, torpedo protective belt device and anti-submarine development.

Figure 9 illustrates an alternate magnetic mine-sweeping plan.

Figure 10 is a short section of one design of my barely oating compound canvas sheathed antitorpedo nets, cut through the center to save space in its illustration.

Figure 11 is a transverse sectional view of the net, taken as on the line II-l I of Figure 10.

Figure l2 is a short section of the lower edge of this device, showing in section one of my automatic depth controlling aquaplanes, with schematic indication of an electro-magnetic remote control gear for changing the depth of'navigation at will.

With further reference to Figure 1.

25 represents a small submarine boat or electric fish fashioned to lead a ship at sea and be electrically operated by remote electric power. This electric power, transmitted through cable from the ship it protects, is greater than any source of power possibly inherently generated in the fish The power required has not only been calculated from skin friction and other engineering data, but checked by actual experiment and reduction to practice with rnodels. The electric lish has also been carefully calculated to have a positive buoyancy when at rest in the salt water of the sea at a suitable temperature, and fashioned to be forced below the surface of the sea to automatically regulated and adjustable depth by suitable aquaplanes and gear devices when under way with its cable loads and other factors,

Here 26 and 21 are standard commercial electric motors, drawn substantially to scale, connected directly to the propellers 28 and 29 for right and left hand drive, respectively, through customary couplings, shafts, stufling boxes and thrust bearings, thereby eliminating any undue tendency to rotate the electric fish about its longitudinal or major axis. What slight rotating torque one motor and propellor may have over the other being cared for by a proper stability of the iish due to a suitable metacentric height of the whole structure, secured through the agency of the buoyant superstructure 30 and the metal ballast castings 3l, 3|, as well as the placing of certain auxiliary motors, 35, 43, 52, 48, and gear as shown below the central axis of the casing 25. The size of this electric sh, here illustrated roughly to dimensions, is of the order of 40 inches in diameter and 32 feet overall length, has a sea water displacement of about 13,000 pounds and houses and oats a pair of three hundred horse power motors.

When the electric sh is confined to the towing of an anti-torpedo belt device as later illustrated and described, the motors 26 and 21 may be of the simple induction, squirrel cage type using three-phase alternating current, but when for the combined purpose of towing the belt device and a countermagnetic mine loop the motors are preferably of the direct current, series connected design as indicated partially by dotted lines indicative of commutators and the necessary brush gear. These motors 25 and 21 may well be of railroad type Where the armatures and elds are series connected, for example, or they may be of universal type for either direct or alternating current with laminated elds in series with armatures, each having a speed of 1800 R. P. M. In an alternate design I have planned for two motors, one with a hollow shaft gear, for example, to enable me to have the pair of turbine type propellers at the stern of the fish instead of one fore and one aft, as illustrated here, but I have compromised in this design to enable one to quickly use standard motors-for the purpose to save valuable time in securing them.

In this design of electric iish the rudder 32 is placed at the bow, in order to give powerful Steerage, since the pull of the protective belt cable is well aft and a rudder at this zone would be less eifective due to the tension there. This rudder is turned by the quadrant of the bevel gear 33, by the bevel pinion 34 and the reversible electric motor 35. The rudder post 32 is conveniently supported in the open bell end 33 which is fashioned rto guard the propeller and at the same time to allow the water of the sea to flow freely through. It may be pertinent to state here that by giving the bell end a bell flare by increasing its diameter just ahead of the leading propeller, increased duty is imposed upon it. Since this electric sh is in eilect a submarine, there is little danger of surface oating debris getting into the leading propeller. Small iish would be quickly cut to pieces, but as previously stated this design has been illustrated. to bring out the The electric motor 35 may of course have addi-Y tional reduction gear between its shaft and the bevel gear 34 and is fashioned to rotate clockwise or counterclockwise at will, receiving current through step down transformer or storage battery (not shown), and controlled by a set of relays, wired radio filters, ampliers, reversing switches and the like (not shown), all responsive to carrier currents generated by oscillators on the convoyed ship and sent over the powervcable by automatic switch gear on the angle controlling winding drum presently illustrated and described in detail.

It is well known that radio waves may be guided by metallic conductors between a transmitter and a receiver insteadl of being allowed to radiate freely through space. This system therefore is ideal 'for the purpose in hand. As a matter of pertinent collateral interest in this connection, it may be stated that energy waves may thus be transmitted distances up to twenty times as great as those attainable Without the assistance of the guiding cable. Conversely it is obvious now that for short distances greater power is available for the control. With proper selection of radio frequencies between, let us say, 20,000 and 500,000 cycles, there is absolutely no interference with the low frequency of the current in the power cable, which may be of the to use conductors of the power cable, whether of alternating current or direct current type, for carrying diferent power impulses at one time, each power impulse using one of the selected frequency channels. These power impulses, of course, amplied at the electric iish for any number of duties apart from the all important one of steering. Among collateral duties which may be imposed may be mentioned Variable depth control of the electric iish to meet the requirements of variable wave height and depth of root. Radio wave energy has been successfully transmitted over telephone, telegraph and lighting circuits, trolley lines and power lines of all kinds for many years. Applicant has the promised co-operation of a nationally known radio engineering design and manufacturing corporation for the reducing to practice of .his remote control by carrier current of the electric sh. 'Complete wired radio diagrams not sh'own.

The depth controlling aquaplane 36 shown in dotted lines in the present view is controlled as schematically represented by the compression spring 3'! and the pressure of the water of the sea, respectively, entering the opening 38 in the open base of the metal bellows 39, and the guided piston 40 and the double lever gear 4I on th'e aquaplane shaft 42.

vThe electric motor 43 is, like the steering motor 35, fashioned to reversable switch gear and relay operation by carrier current and wired radio as previously set forth, for giving the fish a variable depth navigation. From an inspection of this gear it will now be appreciated that the power of the spring member 31 may be increased or decreased at will by remote wired radio control by the operation of the motor 43 whose long threaded shaft 44 (threads not shown) advances the threaded cheek member (threads not shown) against an end of the spring member 31,

Variations in the spring compression, it will now be seen, allows the pressure of the water of the sea in th'e metallic bellows to move the aquaplanes through a more or less angular degree, and therefore to give a greater or less sub-surface travel or navigation of the fish Since the aquaplanes are pivoted centrally, and since therefore the water pressure impressed upon both sides is equal when the fish is under way in the sea, it requires but little power to alter and h'old the angle of lead. Applicant has shown this to be a fact with the model reduction to practice which he has carried out.

The cases 46, 4E and 41 contain step-down transformers, storage batteries and control apparatus as well as servicing equipment and supplies (not illustrated in detail, but necessary or desirable in the operation of the sh).

48 is a small electric motor fashioned to be operated by power from the cable or a storage battery and controlled by a filter, relay, switch and the like by carrier current for rotating at will by remote control its threaded shaft 49 and thereby releasing the threaded draw-bar member 50 which acts as the connecting towing member for the cable attached to the leading member (not sh'own in the present illustration) of the protective belt. This motor operated device to enable a ships master to release the protective belt at any time and thereby possibly cast it adrift should he ever wish to do so. It has been learned that some sea-faring men might wish to have such a ship clearing gear. Here 52 is a, motor driven sump-pump for removing any sea-water which may enter the casing of the electric fish through stuffing boxes, manhole covers, cable entrances and the like through the system of piping substantially as illustrated, and 53 is the casing containing the necessary control equipment and supplies for this sumppump, and such other gear necessary to th'e operation of the electric fish.

54 is a motor operated winding drum for the interconnecting stranded cable or wire for counter magnetic mine work, as will be clearly dealt with in subsequent views. 55 is a water-tight revolvable insulated strain anchor for a power cable 56, and 51 is a xed insulated strain insulator for the cable 58, which may or may not be an electrical conductor, according to the particular design of system employed. Where direct current is employed instead of three-phase alternating current, the system is simplified, the cable 58 being a combined electrical conductor and strain cable, the conducting metal or copper in this cable having a steel core. Such a cable is commercially .known as a copperweld and copperweld-copper conductor, having tensile strengths of from 2 to 21/2 times the strength of hard-drawn copper. The compound conductor comprises a thick weld-on covering of copper, which gives the high strength of steel without danger of rusting in the salt water of the sea. The electrical conductance is the best obtainable of any high tensile strength conductor and the applicant has full necessary data for the power transmission requirements. 59 and 60 are openings Vinto the steel shell 25 in order that cooling sea water may contact the housings of the motors 26 and 21 when they are too small to fit snugly into the shell, being held by the welded members 6I and 62.

It is deemed 4of pertinent interest to state that these motors are heavy duty variety, glass and asbestos insulated, with bearings of ball or roller type packed in heavy grease, for long voyages wit-hout attention.

In addition to the air fan cooling or/and water cooling, a water circulating pump may be added for each motorr (not shown for simplicity). The voltage of the present S-phase induction motors is of the order of 2200 volts, and the current may be standard 60 cycles. The diameter and pitch of the propellers have been worked out to operate direct connected at 1800 R. P, M. for various speeds of cargo vessels and the horse powers required to tow the belts, all based upon actual and practical data in hand. But a full engineering exposition would be outside of a patent specication. Suflice it to say, however, that for two three hundred horse power motors, as illustrated, in the present electric iisl'i, a pair of 30 inch turbine propellers 14 inch pitch, three blade, on 2 inch diameter shafts, would not be far from the correct mark for a 10,000 ton 12 knot freighter, and its protective belt.

With further reference to Figure 2.

Here it is pointed out that the movable aquaplane 3% on its shaft 42, adjacent to the forward end of the fish, is substantially centrally pivoted in order that the water pressure of the sea is substantially the same upon an area before vand aft of the shaft, thereby rendering it easy of angular control. In other words no undue turning effort is required of the metal bellows gear to hold or alter the angle of the aquaplanes when the electric fish is under way in the sea. Actual experiment with models by the applicant has shown that this simple method of depth control is correct, but it is barely possible for the full sized electric ish, that electric motor'control may be more desirable, in which case working data may be easily obtained. In this view it is also pointed out that the twin aquaplane 3S'is xed adjacent to the rear end of the iish, and experiment with a power driven model submarine towing a model belt has shown that a pair of such Xed aquaplanes are quite essential in View of the mechanics of pull and other forces atwork, of the entire submerged system. The angle and area of these xed rear aquaplanes 3S has also been found by experiment to be important, especially important in connection with the applicants design of leading rudder. for the ish.

In his model reduction to practice applicant has many data of interest and value in connection with the submarine belt system, but itV is deemed to be outside of this specification to indicate them all here.

Themultiplicity of openings 59 and 60 through the shell of the fish is, as stated, to allow the cooling water of the sea to carry away the many thermal units of Watt dissipation of the electric motors, transformers and the like within the shell of the electric fish.

The opening 60' which may, or may not, comprise an insulating bushing, and which is centrally located as will be seen, serves for the entrance or exit of a cable or wire for the series connection of the motors in the two electric fish, and also as the source of a magnetic eld in the sea capable of operating the magnetic mechanism of a magnetic mine. The eye bolts 25 25 are suitably screwed into the field casings of the electric motors, to aiord approved lifting points, if, as and when it may be desired or required to hoist the electric fish out of the sea and to swing it upon davits or the like.

With further reference to Figure 3.

Here it is believed that the features in the two foregoing views are made additionally clear and that further description is not necessary since like parts bear like numerals in all of the illustrations.

With further reference to Figure 4.

Here 65 is a plan view of a ship equipped with my proposed stanchions, or projecting platforms 66 and 61, which may be pre-fabricated and be quickly bolted to the sides of a ship. They are somewhat analogous to small gun platforms as applied to gun-boats and cruisers, but instead of pivotally mounting a gun carriage for angular sweep, they pivot at 68 and 68 substantially counter-balanced, yieldable, angle-controlling, motor-operated winding and paying out drums S9, 10, with the counter balance members '10', 10', each drum fashioned to receive one or more cables 1I, 'Il' for supplying electric power and carrier currents to the submerged electric fish 25, 25, which electric fish tow the submergible and submerged torpedo belts 12 and 13 by means of the cables 5|, 5|. As previously stated, upon wired radio impulse of proper selected frequency, electric motors in the electric fish? may be made to unscrew and release the belts, one or both, from the electric iish at the will of the skipper on the bridge of the ship 65.

The skipper may also, through the means of hand gear on the winding drums 69, (not shown here but in a later gure) send the electric fish further out into the sea, as indicated in the dotted lines `5|', 5l', whether they are towing torpedo belts or not. In the drawings no torpedo belts are shown in the furtherout position, because applicant may tow one of a number of alternate protective devices. For example, applicant may tow one of the compound net sheathed belts as later illustrated and described in detail, or he may tow a large meshed steel net fashioned to ensnare the tail of a torpedo in the act of passing through. Such a large meshed steel net offers less towing resistance than. a compound belt, but it has the disadvantages of possibly fouling a screw propeller on making a hard port or a hard starboard turn, and in addition could fail to ensnare a fish torpedo by the tail if said tail is properly guarded in the future.

Applicant may also elect to tow an explosive device fashioned to detonate the explosive in a torpedo warhead when it approaches the device or contacts it. Such an explosive ,device fashioned to be towed will be more fully described later in this spe'ciiication.

Still another alternate device would be a loop, towed well out from the sides 'of the ship and well astern thereof for successively tripping the mechanism in a magnetic mine. Another alternative would be long cables electrically conducting direct currents for counter magnetic mine destruction. All of these alternate devices would require less towing power and consequently smaller electric fish.

For such comparatively small electric sh a smal1 steam turbine operating a generator could well be run with a minimum of space by taking steam from the ships boilers.

Electric power, either alternating current three phase, 60 cycle, or direct current, is generated by the Diesel engine generator set 18, vand can be supplied to the cables 'H and `1 I by suitable regulating gear and leads (not shown in the present drawings). In this Diesel engine drive, the speed of the ship at sea is not reduced. The weight of the Diesel engine generating set is negligible in the matter of the ships displacement. In other words tons or more in a 5000 or 10,000 ton ship would not affect her speed as much as a slight change in the Vtemperature of the sea in which she navigates. excess power over the towing power required of the belts would of course tend to increase the speed of the ship. The electric power may be supplied, however, by a steam driven turbo-generator set, in which case there would be a reduction in the speed of the ship, or the power may be taken from the steam electric drive of a ship by a simple bleeder system.

In the case of taking power from the ships electric drive it may be stated that in many cases the boiler plant may well stand this eXtra demand without reducing materially the ships speed. Again it might be simpler to add an auxiliary boiler than to add machinery-a Diesel electric generating set, for example, if this was found necessary on close calculation.

At 'I9 is a complete duplicate set wired radio transmitting equipment for sending carrier currents at different selected frequencies over the power cables, or over the power cables and salt water of the sea, comprising oscillators, condensers for selective current transmitters and the like for the remote control of the mechanisms in the electric fish as already described. The wiring or connection to the winding drums on the power cables and the grounds to the sea arenot shown in this figure. Y

With further reference to Figure 5.

Here the important scheme of one of the pair of stanchions and counterbalanced, motor operated, pivoted, yieldable, angle controlling, winding 'I'he addition of the slight and paying out drums 'l0 is made clearer. The counterbalance member 'l0' not only counterbalances the drum, but the cable extending into the sea. The drum is restrained against sudden or short duration pulls of the cable and other disturbances, as from the roll of the ship, by hydraulic check cylinders not shown in the present View but illustrated in a subsequent view.

With the present ship G under way, the electric sh 25 and the protective belt 'k3 are shown below the level of the sea, both being capable of being sent still lower-below the deep troughs of the waves of the sea-in stormy weather.

Both fish and belt therefore are not only automatically regulated for fixed depth of navigation, but are controllable for variable depth of navigation by remote control through the agency of carrier currents in the wired or guided radio.

The electric iish has the pair of controlling aquaplanes, one of which is shown here at 36, and the belt device, later described in detail, has a plurality of automatic depth controlling aquaplanes 8D, '89, 8G, presently illustrated and described in detail. The ruddermember 82 of the forward end of the belt 'i3 is equipped with a pair of stabilizing pivoted aquaplanes 83, operated by a gyroscope driven by cable power or storage battery, to insure vertical position in the sea when under tow, or by mechanical means comprising a pendulum hinged to a, beveled pinion, which turns a pair of bevel gears, respectively, turning port and starboard aquaplanes, all as illustrated and described in a brochure entitled New Torpedo Proof Convoy for Freighters at Sea, written by the present applicant and a matter of record at the Massachusetts Institute of Technology, Johns Hopkins University, and Stevens Institute of rTechnology.

Of course applicant has given due attention to the power required of his electric fish to tow such a belt 13 of various widths, and lengths, and at various speeds in the sea, taking into account th-e power required for the depth controlling aquaplanes. This has involved a study of the values of skin frictions, not only of ships, but of various materials considered for the sheaths of his net enclosed belts. The belt is adjusted to be barely floating when at rest, therefore the aquaplane exertion, and consequent power therefor, to overcome the aquaplane exertion, is not great. The fact has been well determined by applicants model belts. Also engineering calculations have been made of the resistance to towing of a smooth surface in salt water, based upon William Froudes classic formula:

R=fsv" where R=resistance in pounds s=area of both sides f=coefcient of friction U=knots 11:1.83 exponent face is one of the least resistant, according to extended researches, to towing in the salt water of the sea.

The drawings, details of which will be shown in subsequent views, have been made from model belt construction, which construction lends itself to any desired width of belt-from let us say, for example, 8 to 12 feet or more.

An eight or ten foot belt navi-gating l5 feet below the surface of the sea is as effective a barrier to the fish torpedo, it will be appreciated from the present illustration, as a much wider belt With its upper edge at water level, and, of course, the narrower the belt for any given length, the less will be the skin friction and consequently the power required to tow it.

Thus it may be seen that the ship may wallow in a heavy sea, with the minimum of strain and stress upon the cable 1| and with practically no strain and stress upon the deeply submerged or submergable electric sh and protective belt.

With further reference to Figure 6.

Here Imore or less schematically represented is a side view of one of the large winding drums slidably or yieldably mounted through the agency of its hollow axle 90 and sliding bearing member 9| in the long slotted guideway 92, which bearing member is resiliently held back toward the hollow central pivoted shaft 68 by means of one of a pair of lug members 93, and the long bar members 94 and the distant head member 95 'and the long compression spring 96, in the long cylinder 9S.

The long bar member 9d terminates in the conically turned end 91 fashioned to make an electrical circuit closure by contact with the adjustable spring members 98 and 99 fashioned to be moved forward or backward by the screw |66 and its hand wheel il. Electric current in the conductors |02 and |03 may be made to flow therefor when the conical end 91 of the long bar member 911 recedes. The conductors |92 and |03 lead to a source of electric current and a proper power controlling device for current to theaforesaid mechanical electric fish.

The hollow shaft S8 is stationary with the pedestal |66 secured to the platform or stanchion 61 by the bolts ll, said shaft extending upwardly through the carriage Illfl for the winding drum, which carriage rests upon the heavy radial and thrust bearing |05 recessed in the upper part of said pedestal.

A flexible insulated electric cable |08 extends from the connections to the cable in the drum 'l0 to and down through the hollow central pivot shaft 68 and is conveniently available in a stationary anchorage at |99 for connection to a suitable source of electric power for the propulsion` of the motors of the electric fish in the sea.

With further reference to Figure 7 Here the drum is shown in partial section to show the reception of four cables-three insulated copper or copper weld steel, power transmission cables, and one bare steel tension cable, possibly consisting of copper plated strands or impregnated with anti-rust compound, for removing all under strain from the insulated copper cables.

ent mechanical cable for strain purposes. For example, there would less strain on the insulation of three comparatively small cables, than upon the insulation of one comparatively large cable.

The cable drum is provided with one or a pair of similar large gears |09 and ||0 positioned and attached to engage the small similar pinions and ||2 of the reversable electric motor |3, supported by the casting |00. Proper electric wiring, switches and starting gear are naturally understood to be present but not illustrated in the interest of simplicity.

The housing ||4 for the three slip-rings and brush gear ||5 for the connection of the conducting cables to the electric sh is made independent of the revolution of the drum through the slip-rings and brush gear at l 6 which represents the exible cable |08 of the previous view.

The double-armed yoke member ||'l, being rmly attached to the hollow shaft $8 remains stationary when the casting |04' turns to the right or left when so led by the tension of the cables running to the electric sh, but the distance through which it may move together with its rate is regulated by the piston rods pivoted at |20 and |2| to the arms of the double yoke member IH. These pivoted piston rods play in and out of the cylinders |22, |23, pivoted at |24 and |25, respectively. The piston heads |26 have one or more minute passages bored through them (passages not shown) to allow the restricted passage of a non-freezing fluid |26 to pass through them. These control cylinders and enclosed pistons and fluids prevent the rapid movement of the drum carriages, as for instance in the roll of a ship in case the cable drums and more or less cable wound upon them, were not precisely balanced by the counterweights In other words, only a prolonged pull of the cables from the electric fish, from right to left or from left to right, respectively, would cause the drum carriage to alter its position, and thereby the position of the tongue member |30 and its spadeshaped end member |3| which is positioned between the duplicate sets of electrical Contact making spring members |32, |33, which spring members may be advanced or retracted through the agency of the insulated gear with screw threads and hand wheels |34 andrl. Thus it will be appreciated thatra steady and prolonged pull of the electric iish to the right or left, and only a steadyr and prolonged pull, will cause the spade-shaped head member |3| to close with the right or left contact making spring members. It is through these right and left Contact making spring members, that the oscillator transmitters for the wired radiolcarrier currents, to the filtered relay, ampliers and switch gear of the reversable electric steering motor in the electric sh, are started and stopped. It is not deemed necessary or desirable to illustrate the complicated connection here, in the interest'o'f simplicity; suice it to say that the comparatively high frequency carrier currents are led into and out of the power cables of comparatively low frequency through condensers indicated schematically at |38 and |39. By means of the hand wheels I3@ and |35, it now becomes evident'that the closeness of the control of the electric fish in their Steerage way in the sea'may be eiected, and when necessary or desirable may be'manually controlled, by simple auxiliary circuit closures and openers (not shown in the drawings).

lWith further reference to Figures 8 and 3.

Here the ship 65 again shown in plan view is equipped with somewhat simpler and narrower, counter-balanced winding drums, for the reception of a single conductor electric cable, insulated' for direct current at 2500 volts, for example, the drums being shown in a reversed direction of pay-out over those shown in Figures 4 and'5.

The present equipment may, or not, comprise a torpedo arresting or torpedo destroying belt 'l2 vand 13 with its cables electrically charged for magnetic torpedo warhead or magnetic mine destruction, and with or without the rear or trailing loop shown specically in Figure 9.

The present equipment may in an alternate case comprise the aforesaid loops and its depth controlling auxiliary shown in Figures 4 and 5 and instead of the belts 'l2 and i3 shown in the dotted lines, merely one or more of the cable elements of the belts may be employed for the purpose of establishing magnetic fields in the sea for the operation of magnetic mines (indicated at Il) and the like, especially the magnetic warheads of this later design of sh torpedo. In the case thebelt is used, however, one or both of the mechanical cables in the belt construction, later illustrated and described, may be insulated electrically and be so interconnected in circuits as to act as combination power cables for the electric fish and magnetic mine and magnetic warhead torpedo destroyers-particularly the latter, since the equipment may be sent down, by remote control, or otherwise tonot only depths just below the troughs of waves in the sea, but far below them to depths greater than the drafts of the deepest ships hulls.

In the present View a steam turbine electric generating set is shown at |40, the electric generator being of direct current design, and possibly of the three wire typeV for grounded neutral. This generator may produce direct current with proper commutator design, of 2500 volts, for eX- ample, and be connected in series with all four of the electric motors in both of the electric sh as shown.

There is no difficulty in generating and commutating direct current lat 2500 volts, a system exemplied by the practice once, if not now, in vogue with certain Swiss railroads, for example. The current in this instance will be for the four 300 horsepower` motors as indicated diagrammatically in the location of the'two towing fish at 25, 25, of the order of 260 amperes, and the copper conductor of the cable may consistof twenty strands or more of copper wire aggregating in circular mills that of a No. 0 wire A. W. G., or preferably such a stranded conductor comprising copper-weld construction for high tensile strength, a subject already dealt with in this specification.

It is of course understood (although not shown) that suitable switchgear is installed for the electric generator set |40. When this is an alternating current equipment we would require the proper generator panels, direct current exciter panels, bus tie, in case two sets of generators are used, and a synchronizing panel.

To secure variation in the towing power 'of the electric fish we must of courseV have means for varying the speed of the electric motors, and it is provided to secure a range of 50-100 per cent speed. This can readily be accomplished by means of engine governor control through electrical connections to the leads |02 and |03 of the Vvided for the leading loop 15.

cf'iunterbalancec'i winding drums, illustrated and described in Figures 6 and '1.

In order to maintain an alternating current generator voltage proportional to the speed, it will be necessary of course to provide ways and means of holding its exciter voltage constant over the speed range. This applicant can do this by furnishing an exciter capable of maintaining rated voltage over the 2 to 1 speed range and then use a voltage regulator, operating in the field of the exciter to hold constant exciter armature voltage. A diactor type of voltage regulator will serve this purpose. When the electric generator |40 is of the direct current type, the question of variation inthe towing power of the electric fish -is even simpler to handle through the agency vE5 for the protection of a vessel following in the wake against one or more magnetic mines.

There is not room enough on the drafting sheet to illustrate Vsuch a loop, in Figure 8, but it is clear that one may be towed as an extension of the conductors of the belt 12, 13. With a loop t towed astern, the center of the loop may have a depth controlling device 11 such as that pro- Moreover, it may have an independent towing cable 15" attached to a ring at the stern of the ship, to prevent the loop from becoming too narrow in form to be effective. In the case a loop is towed aft, the ship towing it relies upon her degaussing system to protect her from magnetic mines. The useful object of the loop towed astern, is to trip' the mechanism in a magnetic mine and explode the same before a ship following may be blown up. Applicant may tow one or more loops (15 and 15") astern, with distances between them, to give one or more magnetic disturbances to a magnetic mine, since some types of magnetic mines require one or more magnetic disturbances to set,

them off.

rPhe rear loop may be in series with the entire vsystem or be in an independent circuit. When the leading loop 15 is not used, and a rear trailing loop behind the ship is used, a return conductor from the electric sh is of course installed. -All of the wiring and connections are so simple and so readily understood by electrical engineers,

that detailed diagrams are not given here.

Thedistance out of this belt device 12, may also be controlled by some alternate design of radiant energy control M5, using an approved radiant energy projecting and responsive system, respectively, with suitable chronograph Y'time factor measurement and control system.

Sound, light, heat, electromagnetic waves, and the like may be employed here on the range- 'nding and deep `sea sounding principles, 'for eX- ample. Such a system could be devised to act as anwalternate plan of control for the wired, or guided radio remote control of the responsive steering devices in the electric fish.

r'The diagrammatic representation of the electric fish 25, 25 in these views includes the diagrammatic representation also of the'wired radio Ysteering gear, showing the motors l35, 35, the ,.storage batteries 35', 35', the rudder-s and gear,

magnetic mines.

32, 32, and the condens-ers, grounds and other necessary devices at 35", 35".

With the present direct current equipment. it is possible through the agency of an oil immersed pole changing switch (notshown) at the generating set |43, to reverse the current flow through the entire circuit at will, without of course reversing the direction of rotation of the motors 26 and 21, because it reverses both in the fields and armatures. Since this is an important feature in operation formagnetic mine destruction, applicant deems it pertinent to explain that to reverse an electric motor of the direct current type, the current supplying it must be reversed in either the iield or armature, but not in both. Since we are by the nature of the electrical connections reversing the current in both when we interpose the pole changing switch, we do not reverse the motors, andconsequently the propellers or the direction of motion of the fish 25.

By reversing the current in the entire system at intervals, however, we reverse the magnetic polarity at the magnetic fields in the sea, and this may serve as a valuable feature in exploding Some magnetic mines may be fashioned to require such changes in polarity, or they may be fashioned to require a plurality of tripping forces in order to explode them. In other words, this ability to change the polarity of the magnetic fields in the sea, adds to the flexibility and possible broader uses of the system in designs of magnetic mines yet to be dealt with.

With the loop 15 as a leading series loop with its float or depth controlling device 11', its destruction by a mine need not stop the electric sh for the salt water of the sea could well act as a return path for the current, especially if the large metallic shell of the fish V25 has been made one electrode. L

With further reference to Figure 9. Here is shown in simple diagram one 'of applicants alternate plans for exploding magnetic mines .for the protection of a ship following in the wake rof the vessel carrying the equipment. The loop floats 11' may be fashioned for the opening of the loop by the crew of va service launch .and moreover at this junction be provided with a coil for increasing the ampere turns, yand lconsequently the magnetic field at this zone.

With further reference to Figures l0 and 1l. Here is illustrated a foreshortened view of a section of one design of my fabricated, vertically floating, barely buoyant, and consequently yeasily totally submerged, submarine low skin friction torpedo-arresting, or torpedo destroying belt devices. The belt device is shown with a por-tion' of the canvas removed in order to illustrate better the woven net. In these particular views the belt device is for torpedo arresting, because of the yieldable hempen net used between the double canvas sheathings, but in an alternate design, a hard strong plane surface may be interposed between the canvas sheathings to vdetonate and destroy a torpedo upon impact. Here are shown factory fabricated wooden float pieces which are mill machined, impregnated with water proof compound and well painted to prevent the absorption of water and consequent change in buoyancy, which would impair or destroy the usefulness of the float. yTwo complementally formed pieces l5!) and I5! of the fabricated and "treated float members are clamped together .by large wood screws 15H', |51', embracing astranded steel cable 152, positioned rloosely inthe cylinldrical passageway |53 formed by joining the opposite oat pieces, `both float pieces being suitably grooved. This cable is here illustrated bare for tensile purpose, but as previously stated for magnetic field purposes, it may be insulated to serve both tensile and electrical conductor purposes. |54 is a canvas sheathing, comprising -one or more coa-ts of marine metallic paint applied upon both sides and simonized by treating with parafl'in, since .parailin has been found by researches in towing plane surfaces in water to offer a minimum of skin friction.

Back of this treated canvas is the stout woven net |55, comprising the horizontal warp members |56, and the vertical woof members |51, the latter of which run up into the well fabricated grooved clamping space, together with an edge of the canvas |54. |54 is a similar sheathing disposed on lthe other side of saidl net. The lower edge of this fabricated belt is clamped between two complementally formed metal sinker members |58 and |58', providing a cylindrical passageway |59 therebetween loosely receiving therein the steel cable |6|. 'I'he metal sinker members are riveted together by the rivets |60, |60. This steel cable |6| may or may not be electrically insulated to serve as an electrical conductor as well as a mechanical strain member, as in the case of its companion cable |52.

Both of the cables, |52 and ll, respectively, may be copper clad, or be of stainless steel, or be of a combination of these two Ways and means to prevent or retard rusting in the salt water of the sea.

The vertical woofs |51 at this lower edge of the belt device, are likewise securely clamped by the metal sinker members |58, as are the canvas sheathings |54 and |54 by the metal sinker members |58.

With further reference to Figure 11.

Here we have a transverse sectional view of Figure 10 showing clearly the two painted and lparaiined canvas sheathings |54, |54 necessary to completely enclose and to prevent the passage of sea water through the network comprising the horizontal warps |56 and the vertical woofs |51 of the net work, as well as the pair of screwed together wooden float members |50 and |5|.

Here we see how the metal sinker members |58 and |58 likewise clamp the sheathings and the warp and woof of lthe net work. At the lower edge of this sinker member, in addition to the rivets |60, |60, the metal sinker members |58 and |58 are securely united by the U bend |62 of the member |58' embracing an edge of the said member securely.

An inspection of this fabricated construction will make clear the easy and quick assembly of the component parts.

An inspection will also make it clear that'applicant may add any number of canvas sheathings, or include between them a net work of stouter ropes, to meet any requirement ofV impact without increasingthe skin friction of this design of belt device.

Also it will be appreciated that a steel net may replace the rope net, provided of course the size of theA impregnated and painted wooden floats are enlarged to care for the added weight of the steel over the hemp rope which latter has substantially negligible weight in sea water.

It will also be apparent that a metal plate may be substituted for -the net work, and be thick and strong enough to cause the destruction of the torpedo by causing the detonation of the explo- 'sive charge in its warhead. Some torpedoes may be fired by the driving in of a contact pin in the War-head, while others must strike a sufficiently resistant surface so as to cause a sufficiently rapid decelerated rate of motion, to cause an inertia device in the warhead to move swiftly and smartly enough to explode the detonator.

Y With such a' hard surfaced and strong plane surface between the canvas sheathings, applicants belt device consists ofa torpedo destroying equipment.

With further reference to Figure 12. Y

In this last illustration We have a short length of the same side view of the belt device, adjacent to the lower or sinker member, as in Figure 10.

Attached to the metal sinker member |58, by means of the rivets |65, |65, is the important cigar shaped automatic depth controlling device |10, with conical or stream line ends, fashioned of sheet metal and adapted to not only automatically set and maintain a sub-surface depth when its belt device is towed at a set speed, but adapted to be controllable for one or more Subsurface depths by remote control from the ship. Therefore it will now be appreciated that both the electric towing fish and the ship protecting belt devices, are automatically controlled as to depth of sub-surface travel, and also remotely controllable and adapted for one or more sub-surface depths by remote controlfrom the ship. This gives the entire equipment ygreat exibility of use, as will be appreciated -by those familiar with the problems involved in combating great seas at times, and in combating deeply planted magnetic mines and deeply launched magnetic warhead torpedoes.

In this cigar shaped device we have the bulkhead member 1|, the compression spring |12 exerting a balancing pressure against the compression spring |13, through the medium of the rigid slidable rack device |14, with its teeth |15 engaging the teeth |16 on the enclosed gear wheel |11 keyed on the shaft |18, which passes through stuffing box bearings (not shown) in the shell of the cigar shaped device |10, which is fashioned to be operative as a depth controlling device when it travels from right to left in the direction of the large arrow above it on the sinker member |58. The shaft |18 carries exteriorly inthe sea a pair of aquaplanes, one on each side of the device, the port aquaplane |19 being shown by dotted lines, said aquaplane for hydrostatic reasons being pivoted at its central zone. As previously pointed out this centralpivoting requires the minimum of turning or angle changing, as well as angle holding power.

An opening into the casing of the device allows the water of the sea to enter the open end of the metal bellows |8|, the opposite end of the bellows being closed to receive the combined thrust of the spring |12 and the pressure of the water ofthe sea when the device navigates below the surface of the sea. The pressure of the sea water is indicated here by the two long arrows.

At the right or stern end of this cigar shaped device |10 is the brass or non-magnetic member |82 centrally bored through and reamed to slidably receive the head member |83 for the spring thrust, and an end of the steel rod |14 which is adjustable in longitudinal travel by the screwV device |15. Y

The solenoid |86, when suiciently energized by .an electric current through its leads |84, |85 of asaoeo its insmatea winding ist', is capabie of adventing the steel rod member |14 and thereby in increasing the tension of the spring |13. This combination of steel rod member |14', the solenoid |86 and the spring |13 is in effect a rugged amperemeter, and is capable therefore, through the toothed rack |14 and the toothed wheel |11 Ato turn thev aquaplane |19 against the'pressure of the spring |12 and the pressure of the water of the sea in the metal bellows |8I, which may be made of brass or stainless steel, in a controllable quantitative manner through the agency of a storage battery and rheostat on the ship. Now as the depth of travel of the device increases in the Water of the sea, the pressure of the water in Athe interior of the metal bellows correspondingly increases, and concurrently the pressure in opposition to that of the remotely controlledtension of the spring |13 also increases, and therefore it becomes apparent that applicant has an automatic depth control device for his protective belt and in addition one for remote variable depth control. Y j

It is obvious that those skilled in the various arts and sciences involved as herein set forth, may vary the details of construction and arrangement of parts, as well as the methods, ways and means of the applicant which enable him to produce the foregoing new and useful equipment for the protection of ships, without departing from the spirit of this invention, and therefore it is not desired to be limited to the precise foregoing disclosures, except as may be required -by the claims.

Having described my invention, I claimt l. In combination a submarine tow boat cornprising a depth controlling device, a motor for activating a propeller on said tow boat, and means operable from a remote point for energizing said motor and for controlling the movement of said tow boat; and a protective device fashioned to guard the hull of a ship from sea-submerged eX- plosive contrivances, said protective device having a flexible connection with said tow boat whereby to be towed at a considerable distance therebehind, said device provided with hydraulically and electrically actuated means for controlling the depth of said device in the water of the sea.

2. In combination a submarine tow boat comprising a depth controlling device, a motor for activating a propeller on said tow boat, and means operable from a remote point for energizing said motor and for controlling the movement of said tow boat; a protective device fashioned to guard the hull of a ship from sea-submerged explosive contrivances, said protective device fashioned to be towed by said submarine tow boat; and remote control means for varying the depth of navigation of said tow boat and said protective device, said means comprising a spring-tensioned aquaplane responsive to hydraulically and electrically initiated pressures.

3. In combination a submarine tow boat comprising a depth controlling device, an electric motor for activating a propeller on said tow boat, and a remote controlled rudder on said tow boat; a protective device fashioned to guard the hull of a ship from a submarine explosive contrivance, said device adapted to be towed by said tow boat; an electric cable connected to said motor and leading to a source of electric power on such ship; and cable receiving means disposed at the side of such ship, said means controlling the angle of lead of the remote controlled rudder of said tow boat in ysure responsive depth regulator for the tow boat,

cable fashioned to supply accordance with the angle made by said cable with the side of such ship.

4. In combination a submarine tow boat comprising nected thereto, a rudder at the bow fashioned to be operated by electric remote control, and a pressaid regulator subject to variation through electric control; and a cable for supplying electric currents for energizing said motor, for operating said rudder, and for variably controlling said regulator, said cable leading to a source of electric currents remote from said tow boat,

5. Apparatus for protecting the hull of a ship from submerged mines and torpedoes, comprising a protective screen for said hull, a tow boat for towing said screen in spaced relation to said hull, and means for variably controlling such spaced relation as well as the direction and depth of navigation of said tow boatv and said screen, said means comprising an electric cable connecting said tow boat with a source of electric power on such ship.

6. In combination, a submarine tow boat comprising a depth controlling device, an electric motor for actuating a propeller on said tow boat, and a remote electric current controlled steering device for said tow boat; an electric cable extending from said tow boat to a source of electric power, one end of said cable fashioned to supply such power to said motor and to said steering device; and a yieldably mounted member receiving the other end of said cable and fashioned to connect it with the source of electric power, the yieldable mounting of said member comprising control means for the current from such powerrsourceto said tow boat. Y

-7. In combination, a submarine tow boat comprising an electric motor for actuating a propeller on said tow boatMand a remote electric current controlled steering device for said tow boat; an electric cable extending from` said tow boat to a source of electric power, one end of said such power to said motor and to said steering device; and a current controlling motor operated winding drum receiving the other end of said cable and fashioned to connect it with the source of electric power, and said drum responsive to the tension exerted by said cable and thereby controlling the current to said tow boat.

8. A motor operated winding drum for an electric power cable and adapted to pay out and` to wind in said cable at will, said drum comprising an axle and a counterbalanced pivoted support therefor, said axle comprising slip-rings and brush gear for an end of said cable, -said support comprising a cylinder, a piston and a fluid in said cylinder for retarding the movement of said support but fashioned to allow said winding drum to turn and assume a position in line with the direction of pull of said cable with respect to said drum.

9. A motor operated winding drum mechanism for an electric cable, comprising a drum, an axle and an electric motor therefor, a slidable bearing for said axle, a pivoted support for said bearing, a spring retarding the slide of said bearing, and a counterbalance for said winding drum.

10. A cable winding drum mechanism for a ship, comprising a stanchion secured to the side of the ship, a pedestal mounted on the stanchion, a revolvable bearing in the pedestal, a substantially counterbalanced carriage mounted on said bearan electric motor and a propeller con@ ing, and a `motor operated `cable winding .drum mounted on said carriage.

1.1. Apparatus for'protecting the ,hull of a ship from submerged mines-and torpedoes-comprising a tow boat having electrically controllable .pro-

.12. Apparatus for protecting thehulltof a ship i from submerged mines .and torpedoes-comprising a tow boat having electrically controllable propellent and navigation direction means, .aprotec- .tive screen attached to said tow boatl forytowing thereby in laterally-spaced .relation to such ship, asource of electric `power :on suchship, .and ...a winding drum mechanism for said cable mounted at the sideof such `ship .and .controlling lthe angle of lead of said tow -boat Kin Iaccordance withthe :angle Imade by said .cable with the .side -of the ship.

.13. ,Incombination-a submarinetow boat comprising a depth controlling device, za 4motor for actuating fa Ypropelleron .said `tow boat,.and means operable -from .a .remotepoint 1for energizing said motor and for controlling the movement oir-said tow boat; a .protective .device tfor the side-of a ship, said .device secured fsolely to `and ltowed by said tow boat in spaced :disconnected relation -to such ship; an electric cable connecting said .tow boat and the ship for supplying currents -toener- .gize said means; :and'radiant energy -means for .measuring the ydistance vof .-'said :protective .device ,from the side of -the ship, and to .substantially -automatically maintain :such measured distance.

14. -An -electric Acable -windingdrum lmechanism V'for a rship, icomprising .a rpedestal secured -to said rship, a fshaft :mounted -vertically vin sai-d `pedestal,

.a carriage mounted -on said shaft -and extending ihorizontally .in Topposite directions therefrom, .a cable rwinding @drum lslidably mounted yinzone end 'portion ofsaid carriageand under spring tension Ito ybe responsive to kthe pull of the-cables, coun- V'terbalance for said drum rmounted von the opposite end of said carriage, and means for supplying .electric currents `to-thecable Wound on said drum.

15. In combination asubmarine "tow 'boat1comlprising a ydepth controlling device, fanfelectric .mo-

.tor'foractivatinga -propeller onfsaid ftow.boat,;and

v'a .remote controlled rudder-on .said .Itow =boat; la .protective 4device vfashioned to guard the hull .of

.favship from a submarine .explosive contrivance, said device adapted to be :towed by saidtowrboat; an electric cable connected to said motor and .leading to a sourceofrelectric power on such ship; andY .radiant energy Vmeans for maintaining .spaced relationship betweensuch ship and said protective device.

l16. Incombinationa submarinetow boat comprisinga depth controlling device, an electric motor for activating a .propeller on said tow boat, and-aremote .controlled rudder on said tow boat; .agprotective device fashionedtoguard-the hull .of a ship Afrom .a .submarine explosive contrivance,

`saidldevice adapted `to be towed by said tow boat;

`an .electric fcable :connected yto .said motor -and leading.torafsourceof electric power on such-ship; .and -phonic .means for maintaining spaced .relationship ,between such ship and -said protective device. I

1.7. iIncombnation a submarine vtow .boat com- .pr-ising -a depth controlling device, fanelectricmo- .torifor activating a .propeller Ion said itow boat, and a remote controlled rudder on said -,towboat; fsa protectivedevice -fashioned rto guard .the yhull of .a ship .from -a submarine explosive contrivance .saiddevice adapted tto rbe towed vby :said 4tow boat; :an electric cable :connected to said motor and leading vtofa source of yelectric power@ on such ship; Aand electromagnetic fmeans for maintaining .spaced relationship between such ship :and -said .protective device.

18. lInfcombination asubmarine tow boat comprising a depth .controlling device, an electric motor for activating a propeller Onsaid'tcw'boat, and a remote .controlled frudderfon said tow fb'oat; .a vprotective device :fashioned -to guard 'the -hull of -a ship .from .a `submarine explosive 'contrivanca said device adapted to be -towed by-saidztow boat; van electric Acable connected .to :said motor and leading to v.a -source of lelectric power on `.such ship; .and vibratory means for-maintainingzspaced relationship between such 'ship and Sai'dfprotective rdevice.

19. vIn 'combinationzasubmarine tow boat :ccml ,prising afdepth controlling device,fan electric -mo- A'tor -for vactivating a propeller on said ltow boat, and -a remote controlled rudder onsaid 'tow boat; a protective device yfashioned :to 'guard'..the hullaof .a vship .from 1a 'submarine explosivetcontrivanca `said device adapted to be towed by said towboat; :an :electric cable `connected to lsaid `motor .and leadingto a source of electric Apower Aon such ship'; land variable distance remote control means for maintaining .spaced relationship between such .ship Eand said protectivezdevice.

MONRGE :HGPKINS

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