US2398794A

US2398794A - Submarine mine

Info

Publication number: US2398794A
Application number: US404608A
Authority: US
Inventors: Wilson R Maltby
Original assignee: Individual
Current assignee: Individual
Priority date: 1941-07-30
Filing date: 1941-07-30
Publication date: 1946-04-23
Anticipated expiration: 1963-04-23

Description

April 3, 1946. w. R. MALTB Y V I 2,398,794

' SUBMARINE MINE Fil ed July 30, 1941 4 Sheets-Sheet l INYENTOR W. R. MALTBY April 23, 1946. w R MAL-[BY 2,398,794

' SUBMARINE MINE Filed July so, 1941 4 Sheets-Sheet 2 INVENTOR W. R. MALTBY April 23, 1946. w. R. MALTBY SUBMARINE MINE Filed July 30, 1941 4 Sheets-Sheet 5 INVENTOR W R. MALTBY vl! lllrl Iii April 23, 1946. w R M Y 2,398,794

SUBMARINE MINE Fil ed Juiy so, 1941 4 Sheets-Sheet 4 INVENTOR w. R. MALTBY I ATTO EY Patented Apr. 23, 1946 I want- SUBMARINE MINE Wilson B. Maltby, Washington, D. 0.

Application July 30, 1941, Serial No. 404,608

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 20 Claims.

This invention relates to a submarine mine of the induction or gradient type in which the mine is caused to be fired by the passage of a steel vessel or any vessel having a ponderance of magnetic material within an effective area adjacent the mine whereby the destructive effect of the mine upon the vessel will be assured. More specifically the invention provides a new and improved submarine mine adapted to be launched from an aircraft in flight in which means are provided for causing the mine to come to rest on the bed of a body of water with the mine in a vertical position.

In devices of this class heretofore devised, it is the general practice to allow the mine to come to rest in a random position determined only by such fortuitous circumstances as may be present incident to the launching of the mine. It is the usual pratice in devices of this character to suspend the mine firing control unit on gimbals, whenever practicable, in order that the firing control mechanism may be placed in a predetermined position regardless of the position of rest that the mine has assumed. In the case of mines employing induction or gradiometer type coils for the control of the firing mechanism, the length of the coil employed precludes the effective use of gimbals for supporting the coil structure and such mines have been subject heretofore to the disadvantages which result from the placement of the axis of the search coils employed in varying degrees of tilt including a tilt to the horizontal position.

One of the objects of the present invention is the provision of new and improved means for directing a submarine mine along a predetermined path of flight when launched from an aircraft, for automatically decelerating the rate of travel of the submarine mine during passage of the mine through the body of water within which the mine has been launched, andfor causing the mine to come to rest in an upright position on the bed of the body. of water.

Another of the objects resides in the provision of new and improved means for rigidly supporting the mine in a predetermined position as the mine comes to rest on the bed of a body of water within which the mine has been launched.

Another of the objects is the provision of means effective as the mine strikes the bed of the body of water within which it ha been launched for engaging the bed at different points whereby the mine is firmly braced in a vertical position regardless oi the contour of the bed with which the mine is engaged.

Other objects and advantages will be apparent from the following detailed description, taken in connection with the accompanying drawings, of which:

Fig. 1 illustrates the invention according to a preferred embodiment thereof;

Fig. 2 is a View in section, somewhat enlarged and partly broken away, of the device of Fig. 1;

Fig. 3 is a view in elevation of the device of Fig. 2 with the fins thereof in open position;

Fig. 4 is a view partly in section and somewhat enlarged of the fin operating and latching mechanism;

' Fig. dis a view taken substantially along the line 5--5 of Fig. 4 with the fin in an extended position;

Fig. 6 is a view partly in section and partly broken away illustrating the fin releasing mechanism; 4

Fig. 7 is an end view of the device of Fig. 6; and

Fig. 8 illustrates diagrammatically an electrical circuit arrangement suitable for use with the presentinvention.

Referring first to Fig. 1 of the drawings there is shown thereon a submarine mine indicated generally by the numeral l adapted to be released-in any well known manner from an aircraft in flight such, for example, as illustrated at 2, the path of travel of the mine being indicated generally by the dashed line 3. The mine is provided with a plurality ofrotatable members or fins 4 pivotally mounted as at 5 but normally restrained from movement until released by a hydrostat responsive to the pressure of the water within which the mine is launched whereby the members 4 are first employed as stabilizin planes or fins to guide the mine along a predetermined line of flight after being released from the aircraft and are subsequently employed to decelerate the mine during the descent'th'ereof through the Water whereby the mine will strike the bed of the body of water at a somewhat reduced rate of travel. At the instant of impact with the bed, the members are quickly brought into engagement with the bed thereby to maintain the mine securely braced in an upright position regardless of the contour of'the bed of the body of water with which the mine is engaged.

The mine is provided preferably with a piercing member 6 adapted to penetrate the bed of the body of water and prevent substantial movement of the mine from any cause such, for example, as the action of tidal currents or a shifting condition of the bed. As illustrated'on Fig. 1,

the mine is adapted to be braced in a vertical position on a relatively level bed of a body of water, on an inclined portion of the bed or upon a rock or reef such as illustrated at 1, 8, and 9, respectively.

On Figs. 2 and 3 is shown a submarine mine according to a preferred embodiment of the invention comprisingacasing l l towhichis afiixed the piercing member 64 The casing-isprovided' with a tapered portion l2 having .a cylindrical member l3 secured thereto as by the bolts I4,

suitable gasket [5 being provided preferably to insure a watertight connection between the cas ing and the tapered portion I2. member I3 as bythe bolts I6 is the member IT,

a suitable gasket I8 being preferably inserted-- therebetween to prevent the seepage of zwatei" within the mine. The member I1 is provided with a bearing support or strap l9,-iFig-.' 6;-secured:

thereto in any suitable manner as by the bolts 2 I, and having a bearing;22 therein in alinement with the t bearing- 23; whereby the" hydrostat plunger-24 is slidably-supported. Aflexibledia phragm 25 is secured in sealed relation to-the position illustrated -unti'l the:mine has attained a;

predetermined depth of submersion withingthe water,- at:w-hich;- time the pressure of the water against the flexible diaphragm 25 'causesith'e extending members 3| of the latch 29 to be With-- drawn from looking engagement with the'finretaining hasps 33;pivotal-ly;secured to the fins as by the pins 34.

Anarming wire .35 passes throughan aperture 36 within the plunger rod 24 and the bearing sup-v ports ,3! extending ;from the-memberwlv'l whereby thehydrostat is prevented from movement until, after the arming wire is Withdrawn. ThearI-ning wire extends through an aperture .38 --withi n the member; I 1 and issecured'at the other end thereof;;to the aireraft WherebYJthe arming wireisw-ithdrawn fromthe mine-as the'mine ,fallsawayrii om,

the aircraft.- 1

mped: to th mi i ca in I l as by the bolt 39 is; an adjustable support 140 comprising ;fou r bearing, pieces 4 I and a plurality g-of brackets-(42 adaptedto receive a bearinggpin: 43 held in posirotatable member '45 having; a ratchet device 46 grooved arcuate portion 50 of the ratchet 46 and is guided by a suitable grooved pulley pivoted on the bearing shaft 51 supported by the bearing pieces 4|. A pair of

pawls

58 and 59, Figs. 4 and 5, are pivotally supported on the shaft 51 and urged by the springs BI and 62 respectively encircling the pin 53 toward the ratchet 46 until arrested by the @portion;-;-64- there0f whereby the pawls are preventedjfrom engaging gthe arcuate portion 65 of the ratchet and are efiective to engage any of the teeth 66 of the ratchet as the fin '45 is moved to an extended or open position. Pawl 59, it will benoted, is preferably somewhat longer than the pawl- 58 by an amount substantially one-half theidistance between the tips of adjacent teeth 66 of the ratchet, thereby providing an arrangementimwhich the angular distance between successive locking positions of the fin is one-half the angular .,distance1b'etween successive teeth of the ratchet. Thus, larger teeth on the ratchet may be employed in: which the strength of the ratchet mechanism -is;' substantially l increased: This 'arrangement is clearly ;shown- -on-Fig. 5 by reason of-the fin Ali-having been rotated, for purposes of illustration,- through. an angular distance of- 90 degrees from-the-position shown: on Fig. 4.

The support55:is:of-a shape adapted to engage.

and additionally support the fin 45 during the fiightof the mine in-the air and the passage of themine throughthe :water until-the vhydrostatt 25 has released' the fins which are moved bythe: springs 52 out of enga ement with the supportsv 55. By pivotally supporting the fins" at. the pins 43 and additionallysupporting the finsyby means of; the brackets 55 in the manner herein disclosed;

the 'fins are rigidly held vin-a predeterminedw 1305i? tion in alinementwith the axis of the mine wherebythe mine follows apredetermined line of flight and maythus be plantedlin a predetermined" location with a high degree .of accuracy.

Attached ;to-;the adjustable support- 148 in substantial;alinement'with'therfins 45'are thev or wedge shaped members 61 whereby, during the descent \ofithei-mine withinr'the water; after the fins r-have'beenire'leasediby the hydrostat, the

members 67 deflect the pressure of the water from the finssufiiciently :to'permit the Lfins to 'bepartially:,extend'ed {by the. springs-"52 m the .manner secured thereto in any;suitablemanner such,;for 7 example, as by; welding .jOI brazing ,:the parts together is pivotally mounted .on the pin} 43 Where? by the member 45 may be rotated to different positions as will more clearly appear as thedescri-p tion, -procee,ds.- The member :45 is generally. U-v

shaped, Fig.:7, and provided-g; with {reinforcing strips secured thereto; such; foniexample as the,

channel fshapedpieces '41,. illustrated:

A: flexiblev ,;cable. 148; Fig. .4, 4 of steel, oresimilar material suitable for @the purpose, :is: secured; at-

one, end thereof to the ratchet .41'3,as.b'y'theplate- 49' and bolts 5 l, and. at the. other-Lend vthereof ;to a retractile spring; 52; :asgbyvthe clamp; 53 and bolt 54.- The'o'ther end of the retractile spring "is attached-to a supp0rt 55 securedtovthe casing-ofthe mine wherebythe ,retractilespring. is' maine.

tained in tension sufficient to ;cause -the ;fin- 45 to. be actuated to the, open position-shown; on Eig;-;3.- The; cable- 48 passes 1 along a-soom-pl ernentary;

shown=onFig;;l.- The rate of descent of the mine is thus diminisheddmtil the minelstrikes the bed of the ,body ofwatenrat; FWhiCh: time the inertia. of the partially extendedxfihsiis employedto assist the springs 52 in quickly lowering the fins into engagement Withthe bed of the body'of-water before the -mine-has tilted'by an appreciabl'etamount' fr-ornvthevert-ical position; Each of the'fins is restrainedfrom-reverse movement by the pawl 58 or :59; as thecase' may-"be, wherebyithe mineis positively gset =to a'predetermined' :verticat position.q The adjustable-support 148 may; if desired,

' m t: different positions with respectito the mine casing l l2 whereby-the position of thefins 45 may be varied at will in accordance with' the degree ofshardness of thebed-ofi thegb'odyof water within-which the mine'is; tube-planted. A p111- rality of holes 60*are'provided-in each ofthe ifins 45 wherebythe-ha-sp 1maybe pivotally secured thereto byjthe pin: :34 at-'different: positions in accordance withthe adj-us-tedpositionv'of the support;40. .If foreXamplerthe-m-in'e isto belaunched in a 'bOdYTDf water having arrelatively. soft :bed,

it, maybe :desirable, in: viewro-f, the a greater pene trationgofthemine within the bed before coming.

to'reshto arrangethe support '40 somewhat-nearer the tail of the mine whereby the.vfins;45 :maynbe.

employed to greater advantage in supporting and maintaining the mine in a vertical position.

. The operation of the mine firing mechanism will now be described. Assume, by way of example, that the mine has been launched and is resting on the bed of a body of waterin a vertical position with the fins thereof locked i supporting engagement with the bed and that sufficient time has elapsed after the mine has been launched for the soluble washer 68 to dissolve or soften sufficiently to allow the hydrostat 69 to be operated by the pressure of the water. When this occurs, the detonator H is inserted into the booster charge 12 within the casing 13 and the electrical contact members M are brought into engagement with each other by movement of the collar 75 preferably of insulating material suitable for the purpose such, for example, as Bakelite, rubber or the like, afiixed to the hydrostat.

A battery BA is provided within the compartment 16, Fig. 6, and insulated therefrom by suitable yieldable material such, for example, as sponge rubber or the like in the manner illustrated and in circuit with the armature spring I! of relay F, the circuit being continued by way of the cable duct '58 to the hydrostat contacts i5 and thence to the detonator H. A search coil SC preferably having a magnetic core 80 therein is operatively connected to the winding of relay F as by the conductors l9 and adapted to operate the relay in response to a changing field detected by the search coil within the effective destructive area above the mine. Thus, the electromotive force generated by the search coil, as a steel vessel passes within the effective area of the mine, is of sufiicient strength to operate the relay F and cause the detonator to operate and fire the booster charge 72 thereby causing the main charge 19 to explode the mine.

Whereas the preferred illustrative embodiment of the invention has been described with particular reference to a submarine mine in which an induction coil is employed to control the mine firing mechanism, it will be understood that the present invention may be applied to mines in which the presence of a steel vessel is detected by search coils of the gradient type wherein the diiferential voltages induced within the search coils by the moving vessel is employed to fire the mine. The invention may also be employed with mines in which the detecting mechanism is preferably directionally disposed such, for example, as mines employing acoustically controlled detecting mechanisms.

Briefly stated in summary, the present invention provides means for guiding a submarine mine both through the air and in the water along a predetermined line of flight and causing the mine to come to rest and be braced in a vertical position on the bed ef the body of water within which the mine has been launched. Thus, by reason of the predetermined position of rest of the mine, the area detected by the detecting mechanism is reduced and a more effective use is made of the mine for the purpose of disabling or destroying a vessel.

While there is shown and described herein a certain preferred embodiment of the invention, many other and varied forms and uses will present themselves to those versed in the art without departing from the invention, and the invention, therefore, is not limited either in structure or in use except as indicated by the terms and scopeof the appended claims.

- The invention herein described and claimed may be manufacturedfand used by or for the Government of the United States of America for governmental purposes Without the payment of any royalties thereon or therefor.

What is claimed as new and desired to be secured by Letters Patent of the United States is: 1. In a mine ofthe character disclosed adapted to be laid on the bed of a body of water, a mine casing having a plurality of fins pivotally secured thereto and settable to an initial position and to a final position in which the fins are adapted to support the mine in a predetermined position on said bed, means for locking said fins in said initial position, means eifective during the descent of the mine through the water for causing the fins to be released from said locking means, and means for actuating the fins to said final position as the mine strikes the bed of the body of water within which the mine has been launched.

2. In a mine of the character disclosed adapted to be laid on the bed of a body of water, amine casing having a plurality of fins pivotally secured thereto and settable to an initial position and to a final position in which the fins are adapted to support the mine in a predetermined position on said bed, means for locking said fins in said initial position, means effective during the descent of the mine through the water for causing the fins to be. released from said locking means, means for actuating the fin to said final position as the mine strikes the bed of the body of Waterwithin which the mine has been launched, and means for retaining the fins in said final position.

3. In a mine of the character disclosed adapted to be laid on the bed of a body of water, a plurality of rigid members pivotally secured to said mine adapted to brace the mine in an up-' right position as the mine comes to rest on said bed, means'for maintaining the members in a closed position as the mine is launched, means including a device responsive to the pressure of the water within which the mine is immersed for releasing said rigid membersand means eiTective as the members are released for actuating the members to an open bracing position.

1 4. In amine. of the character disclosed adapted to be laid on the bed of a body of water, a pluralityof rigid members pivotally secured to said mine adapted to brace the mine in an upright position as the mine engages said bed, means for maintaining the members in a closed positionas the mine is launched, means including a device responsive to the pressure of the water within which the mine is immersed for releasing said rigid members, means efiective as the members are released for actuating the members to an open bracing position, and means including a ratchet mechanism for locking said rigid memb'rsin' said open bracing position.

, 5. v In a submarine mine adapted to be launched froman aircraft in flight, the combination of a plurality of fins pivotally secured to said mine, fin actuating means for pivotally moving the fins from a predetermined initial position to a final position in which'the fins are adapted to support the mine in a predetermined launched position, means for retaining said fins in said predetermined initial position, an arming wire secured to said aircraft and adapted to unlock said fin retaining means as the mine falls away from the aircraft in flight, and means for rendering said fin retaining means inefiective to maintain the fins insaid predetermined initial position during the travel of the min'eathrouglrthe b'odybf water within-which the mine {is launched 6. Ina submarine-mine adapted to be laun'che dplurality of fins pivotall y securedLtO saidimine; fin actuating means for pivotally movi-ngthefins from a predetermined ini tial position' toa finalposition in which the fins' are' adapted to support the mine in a predetrmi-ned -lafihch'ed position," means for retaining saida fin'sin saicl prede'ter mined initial position; an arming wire seeured to said aircraft and adapted -to' unlock said -fin-v-re taining means as "the-mine falls away from'=the-' aircraft *in flight, means for rendering said fiii retainingmeans ineffective-to maintain'the fins in said predetermined initial position during the travel of the mine through' the body of water within which the mine has -'been"launch'ed,- and means secured to saidminefor causingthe fins to be'actuated to a predetermined setting '''during the descent 'of -the mine-through said body of water." 7

'7. In a'mineof the character-disclosed adapted to be launched'from an aircraft infiig'ht,- the com-'- bination of a plurality of rigid members pivotally and releasably secured to said mine for directing the mine along a predetermined lineof 'fiight," means effective during thedescent of the-mine through the water for releasing said rigid mem b'ers,"and means efiective as the-mine strikes the bed of the body of water for causing said'rigid members to be actuated into engagement with said bedvariably, in accordance .With the contour of said bed thereby to'support the mine'inavertical position.

8. In a mine of the"characterdisclosed adapted to be launched from an aircraft in"flight,"the combination of a pluralityrof rigid memberspiv; otallyand releasably secured "to saidrniriefor di recting' the mine along 'a predetermined line of flight, means effective'duringqthe descen'tof 'th'e mine "throughith'e water for releasing "said frigid members; means effective as the 'mine strikes" the bed "of the body "of'wate'r for causing said" rigid members to "be iactuatedvariablyto' positions in engagement with said bed infa'c'cordan'ce with the contour :of the bed "thereby "td support 'Isai'd' mine in a vertical position; and .nieansfor looking said members-in said actuatedpositions";

9; Ina submarine mine adaptdto be launched froman aircraft 'ififiight," mean's' efiective'as the mine comes torest on'the bed of"a.body'"oi"water within whichthe' "mine has"beemlaunched'ifor enga'gingsaid bed 'and' supporting the mine ma redetermined-- position? means for-locking ".sa'id minesupporting "means in *an initial position: an armin wire secured to said" aircraft for removing a restraint said*lockingfmeans-"as the "mine falls away fromsaidaircraft;means controlled by thepressure of=the*water for rel'easing saidddck ing means, mean's for-" actuatihg "said*minesup-"- porting means to a position"in whichthe rate'of travel of the mine-through the wateris reducedand foraddition ally'actuatingthe mine support ing means as'the mine strikes said-bediandmeans forlatching said bracing means '-iriengagement with the bed-bf the body of water inaccorjdance 7 with'the contour of said bed i 10. -In' a mine of the character disclosed adapted to be launched from an aircraft infiightfthe combination of'a pluralityof fins"pivotallyse cured to said mine, meansfdractuating'said-fins to' different-'-positions,--a "ratchetmember secured to ea'ch' of saidfin's having a pluialityof ratcht' teeth 'thereon; a ai1- ori aw1s adapt d toenea' e the teethi ii of I each: ratchet --member alternately as thevfin' is a'ctuated to successive positions for lockin'gieach'of said fins in different positionsin accordance wit'h the contour 0f the bed of the' bodylof water with which the fins are engaged;

11. In a mine of the character disclosed adapted tobe launched from an aircraft infiightthe combination "of a plurality of fins pivota'llysecured to said mine, means for actuating said fins tozdifierent positions; a ratch et member securedto each of'said fins having a plurality of ratchet teeth thereon, a pair of pawls adapted to engage the te'eth ofeach ratchet member alternately as the fin is actuated to successive positions for lockingeach of said fins in different positions in-accordance with the contour of the bed of the body -of water with which the fins are engaged,- an'dmeansfoir urging said pawls against said ra'tchet member. a

12. In a submarine mine adapted to be launched from an aircraft in fiight, a plurality'of fin'members for controlling the flight of said mine through the air, a plurality of pivot supports'for-said fins, means for moving said fins into engagement with the bed or the body or water within which the mine has been planted thereby to support the mine in a predetermined position, and means for adjusting the position of said pivot supports in'acoordance with the predetermined degree-of penetration of said bed by the mine;

13; In a submarine mine adapted to be released from an aircraft in flight, a plurality of fin members for controlling the flight of the released mine, means for pivotally supporting said fin members, means for locking said members in an initial position, means controlled by the pressure of the Water within which the mine is submerged for simultaneously releasing each of the fin members from said locking means, and means adapted to actuate said fin members to an outwardly eX- tending open position in which the fin members are adapted to decelerate the descent of the mine within the water as the members are released bysaid releasing means. 1

14; In-a submarine mine adapted to be'launched from an aircraft in flight, the combination of a mine comprising a casing having a plurality'of movable members pivotally secured thereto and settable to an initial guiding position andcto'a final" bracing 1 position, means for holding the members in said initial position, a ratchet individual" to each of said members and secured thereto; aplurality of pawls adapted toengage the teeth" of each ratchet respectively and to retain the members in said bracing" position,

means for releasing said holding means during the descent of the mine Within the body of Water, and "means including a flexible member in operative connection with each of said ratchets re-' spectively for actuating said members to said final in flight and having a plurality 'of movable fins for "guiding the mine along a predetermined line of flight, a mine casing, means connected 'to'the casing for pivotally'supporting said fins. means for preventing movement of the fins from'an initial position until the" mine has been submerged to a predetermined depth within a body of'water, means including a spring device for actuatingeachof said-fins to anoutwardlyextendingppen'pos'ition in which thefins are adapted to decelerate the descent of the mine within the water, means secured to said casing and adapted to be enclosed by the fins while in said initial position for additionally supporting the fins, and means for connecting said spring device to the last named fin supporting means.

16. In a submarine mine of the character disclosed comprising a plurality of rotatable fins adapted to be actuated to a position in which the fins are adapted to support the mine in a predetermined launched position, the combination of ratchet mechanism rotatable with each of said fins, means for actuating said fins, a plurality of pawl devices for engaging the teeth of said ratchet mechanism variably in accordance with the angular position of said fins, a pivot support for said pawl devices, means adapted to urge the pawls into engagement with said ratchet mechanism, and means for preventing the engagement of said ratchet mechanism by said pawls until the fins have been rotated by said actuating means through a predetermined degree of rotation.

17. In a submarine mine of the character disclosed, the combination of a mine casing having a plurality of fin members pivotally secured thereto and locked in an initial position, means including a device responsive to the pressure of the body of water within which the mine has been launched for releasing said fin members for rotation, means for actuating said fin members to a final setting in which the mine is braced in a predetermined position as the mine comes ot rest on the bed of said body of water, a water hydrostat h'aving contact means adapted to be closed as the hydrostat operates in response to a predetermined degree of pressure of the water within which the mine is submerged, means including a relay for detecting the presence of a vessel within an effective destructive area, detonating means, and means including a firing circuit adapted to be closed jointly by said contact means and said relay for causing the detonating means to explode the mine in response to the operation of said sensing mechanism.

18. A submarine mine of the character disclosed adapted to be laid on the bed of a body of water, a casing for said mine having a plurality of bracing members pivotally secured thereto and settable to an initial position and to a final position in which said bracing members are adapted to brace the mine in a predetermined position on said bed, means for releasably locking said bracing members in said initial position, a hydrostat device having means for causing the bracing members to be released from said looking means as the hydrostat device operates, means adapted to actuate the bracing members to said final position, a plurality of stop members secured to said casing within the path of travel of said bracing members for arresting the bracing members in said final position, and a plurality of ratchet devices respectively associated with each of said bracing members for locking the bracing members in said final position.

19. A submarine mine of the character disclosed adapted to be launched Within a body of water from an aircraft in fiight, a plurality of fins pivotally secured to said mine, normally locked means for releasably retaining said fins in a predetermined initial position, an arming wire secured to the aircraft and adapted to unlock said fin retaining means as the mine falls away from the aircraft, means responsive to the pressure of the water within which the mine is launched for rendering said fin retaining means inefiective to maintain the fins in said predetermined initial position, and means secured to said mine for causing the fins to be actuated variably to different positions in which the fins are adapted to support the mine in a predetermined position on the bed of said body of water in accordance with the rate of travel of the mine through said body of water.

20. In a mine of the character disclosed adapted to be launched from an aircraft in flight, the combination of a plurality of rigid members pivotally secured to said mine for directing the mine along a predetermined line of flight, means for releasably locking said rigid members in an initial position, means effective during the descent of the mine through the water for causing the rigid members to be released from said locking means, and means for yieldably urging said rigid members outwardly from the mine to different an gular positions in accordance with the rate of travel of the mine through the water thereby to vary the effective brakin area of the members until a uniform rate of travel of the mine is reached.

WILSON R. MALTBY.