Pivoted vehicle launch for submarine

The launching of a vehicle having front and back ends, from the submerged ll of a vessel that is moving forward through water by allowing the vehicle to pivot outboard clear of the hull, preferably from a launchway cavity, into the flow stream where it is released to move under its own propulsion and/or buoyancy forces. A first mechanism is carried on a submerged exterior surface of the hull and connected to the front portion of the vehicle, for initially supporting the vehicle front portion adjacent to the hull in the direction of hull travel, and then selectively releasing the front portion of the vehicle from the hull so that the front portion can move laterally away from the hull into the flow stream. A second mechanism is connected between the hull and the back portion of the vehicle, for initially providing stationary support to the back portion of the vehicle adjacent to the hull while the first mechanism supports the front portion, and then providing pivoting support to the back portion as the vehicle front portion thereby swings away from the hull. Structure is provided to cooperate with the first mechanism, for urging the front portion of the vehicle laterally away from the hull as the front portion is released by the first mechanism.

BACKGROUND OF THE INVENTION 
(1) Field of the Invention 
The present invention relates to the launching of vehicles from the 
submerged hulls of vessels, and more particularly, to the launching of 
vehicles such as torpedoes, missiles, mines, countermeasures and 
autonomous underwater vehicles (AUV's), from the hull of a submarine. 
(2) Description of the Prior Art 
Conventionally, vehicles such as torpedoes, missiles, mines, or 
countermeasures (hereafter called vehicles) are launched from a submarine 
hull through a torpedo or launch tube. The launching imparts longitudinal 
motion of the vehicle through the tube, which carries the vehicle down the 
tube and out of the submarine hull form into the water flow stream outside 
the moving hull. 
In general, the vehicle is launched either obliquely against, or normal 
(perpendicular) to, the flow stream outside the moving hull. In order for 
the vehicle to clear the hull, it is propelled initially by pumped water 
or compressed air introduced behind the vehicle in the tube. A significant 
amount of energy with consequent acoustic noise generation, is associated 
with the launch. Not only does the conventional launch technique create 
significant acoustic noise, but the ejection system requires substantial 
volume and weight allowances internal to the submarine. 
Because the vehicle is constrained by the launch tube walls from freely 
reacting to the hydrodynamic force due to the flow field (which urges the 
vehicle to yaw and translate off the launch tube axis), the vehicle can 
experience damage from impact and varying loads while riding on or hitting 
against the launch tube wall. Also, the resulting disruption to the 
intended trajectory can prevent the vehicle from stabilizing after launch. 
Moreover, vehicle designs are limited to configurations and geometries 
that can interface with, and accommodate contact against, the tube during 
launch. In many cases, the submarine speed related launch envelope is 
restricted to prevent damage to the vehicle or to insure controllability. 
SUMMARY OF THE INVENTION 
It is, accordingly, an object of the present invention to quietly and 
efficiently launch vehicles, particularly torpedoes, missile, mines, 
countermeasures and AUV's from submerged hulls, particularly submarine 
hulls. 
This is accomplished by allowing the vehicle to pivot outboard clear of the 
hull, preferably from a launchway cavity, into the flow stream where it is 
released to move under its own propulsion and/or buoyancy forces. 
In a general sense, the invention is directed to a system and method for 
launching a vehicle having front and back ends, from the submerged hull of 
a vessel that is moving forward through water. A first mechanism is 
carried on a submerged exterior surface of the hull and connected to the 
front portion of the vehicle, for initially supporting the vehicle front 
portion adjacent to the hull in the direction of hull travel, and then 
selectively releasing the front portion of the vehicle from the hull so 
that the front portion can move laterally away from the hull into the flow 
stream. A second mechanism is connected between the hull and the back 
portion of the vehicle, for initially providing stationary support to the 
back portion of the vehicle adjacent to the hull while the first mechanism 
supports the front portion, and then providing pivoting support to the 
back portion as the vehicle front portion thereby swings away from the 
hull. Structure is provided to cooperate with the first mechanism, for 
urging the front portion of the vehicle laterally away from the hull as 
the front portion is released by the first mechanism. The vehicle is 
released from the second mechanism, and thereby launched from the hull, 
either under its own propulsion power, or from the momentum as a result of 
the forward motion of the vessel. 
Preferably, the hull includes a launchway formed as a cavity external to 
the pressure hull, and large enough to receive completely the vehicle as 
supported by the first and second mechanisms. 
In one embodiment, the structure for urging the front portion laterally 
away from the hull is in the form of an inlet channel forward of the 
launch cavity. The channel produces a vigorous flow of water between the 
cavity wall and the front portion of the supported vehicle. In another 
embodiment, the functionally equivalent structure is in the form of a 
piston or a pneumatic or hydraulically operated arm for moving the first 
mechanism in a direction outboard of the cavity, before release. 
The launch system and method in accordance with the invention uses 
significantly less energy than conventional techniques, because only 
pivoting motion to the vehicle needs to be developed. Hydrodynamic forces 
present as a result of the vessel's forward way, provide the bulk of this 
energy. 
Because the vehicle is positively controlled and restrained to motion in 
the pivoting plane during launch, yet is free to move in response to the 
hydrodynamic forces acting on it, there is no chance for damage to the 
vehicle. The vehicle external configuration is virtually unrestricted with 
the exception of providing appropriate interface to the pivoting 
mechanism. 
With the present launch method, the typical torpedo launch pump with its 
associated weight and volume requirements, is eliminated. This affords 
more vehicle storage room, or the option of a smaller submarine having the 
same weapon stowage as a larger conventional submarine. 
The invention is compatible with the launch of vehicles stowed external to 
the pressure hull in the free-flood spaces of the submarine, or stowed 
internal in a torpedo room from which a transfer tube would be utilized to 
position vehicles into a launch cavity external to the pressure hull.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 shows a submarine hull 10 and region 12 where vehicles may be 
launched in accordance with the present invention. This hull region 12 has 
a transfer tube 14 through which each vehicle 16 is delivered from stowage 
internal to the hull to a position in a launch cavity 18 formed as a 
recess in the hull 20. Preferably the launch cavity 18 is deep enough so 
that the vehicle 16, as supported therein, remains within the overall 
envelope of the hull 20. 
In accordance with the invention, the vehicle 16, once positioned and 
secured by one or more mechanisms 22 in the cavity wall, is launched 
according to the following sequence. First, the vehicle 16 is pivoted 
outboard of the cavity 18 and hull 20, into the flow stream passing over 
the hull, and secondly, it is released and carried outboard away from the 
submarine hull due to the hydrodynamic forces and forward momentums to the 
submarine's forward motion through the water. In the first and second 
embodiments to be described below, the first step of pivoting the vehicle 
outboard of the cavity, is accomplished by an active mechanism 22, under 
hydraulic, or similar mechanical action. In the third and fourth 
embodiments described below, the pivoting of the vehicle is accomplished 
passively by a flow of water that is delivered through a channel 24 formed 
in the hull forward of the cavity 18. This delivers a vigorous flow of 
water between the cavity wall and the forward portion of the vehicle, 
producing an outward pivoting force on the vehicle. With all embodiments, 
a door preferably covers the launch cavity 18 during normal submarine 
maneuvers, but is retracted to expose the cavity preparatory to the launch 
mode of operation. 
FIG. 2 is a diagrammatic view of the vehicle launch region 12 of the hull 
looking downward in the view of FIG. 1. The vehicle 16, is advanced 
through the transfer tube 14 so that the forward portion 26 passes through 
a ring 28 or similar clamp which is supported through the wall 30 of the 
launch cavity 18. The clamp 28 is pivotally supported at 33 on an arm 32 
which is connected to a piston and hydraulic or pneumatic cylinder 35. The 
cylinder 35 is pivotally connected as shown at 37, for movement 
substantially in the plane of the sheet of drawing. Thus, the arm 
mechanism 32 is adapted to move in the longitudinal direction 34 of the 
cavity, between a first position, at the left-most portion pressure box 
36, to the forward-most position shown in FIG. 2. This enables the clamp 
28 to be in a position near the exit 38 of the tube 14, for clamping and 
maintaining support on the front portion 26 of the vehicle 16 as the 
transfer tube ram 40 pushes the vehicle out of and beyond the tube exit 
38. 
Thus, in the armed mode, the embodiment of FIG. 2 has a first mechanism 28 
carried on a submerged exterior surface of the hull and connected to the 
front portion 26 of the vehicle for supporting the front portion adjacent 
to the hull in the direction 42 of hull travel. A second mechanism 40 is 
connected between the transfer tube 14 and the back portion 44 of the 
vehicle, for initially providing stationary support to the back portion of 
the vehicle adjacent to the hull while the first mechanism 28 supports the 
front portion of the vehicle. 
To initiate the actual launch, a third mechanism, the support arm 32, is 
extended transversely to the longitudinal direction of the cavity and the 
vehicle, whereby the nose portion 26 is moved outboard of the hull 
envelope 20, into the external water flow stream 46. At the same time, the 
ram 40 has a joint 48 which pivots to maintain the back end 44 of the 
vehicle in, or very close to the cavity. The external flow 46 impinging on 
the inboard surface of the vehicle facing the cavity, produces an outboard 
force 55 tending to urge the vehicle nose 26 even farther from the cavity. 
At the appropriate pivot angle, the vehicle is released from the clamp 28, 
so that the vehicle is launched to its target or destination. Preferably, 
the clamp 28 is controlled so that it automatically releases the front 
portion 26 of the vehicle when the arm 32 has extended along path 50 a 
sufficient distance to assure that the nose 26 is outside the launchway 
cavity 18, as shown in phantom at 52 in FIG. 2. The flow 46 then pivots 
the torpedo even farther outboard, as shown at 54, where the back end of 
the vehicle 44 is released from the pivot arm 48. 
It should be appreciated that a variety of alternative pivoting mechanisms 
for supporting the nose portion of the vehicle can be utilized with the 
present invention. The first support mechanism enables the clamp 28, and 
thus the nose portion 26, to follow an arcuate path centered around pivot 
48, until the vehicle is released. The most efficient way in which to 
enable the clamp to move both longitudinally during the loading and arming 
of the vehicle, and then pivotally on an arc in the plane of the sheet of 
drawing as shown in FIG. 2, is to provide pivot connections 33 between the 
clamp and the rod 32, and another pivotable connection 37 between the 
piston cylinder 35 and the cylinder support internal to the hull. It 
should also be appreciated that arm 32 could alternatively be pivotally 
connected to a member (not shown) adapted to be hydraulically or otherwise 
powered to move longitudinally along the direction of arrow 34 on a 
sliding track in box 36. Those skilled in the art could easily design 
equivalent implementations actuated by a ball screw with rotary actuator 
and equivalence. 
FIG. 3 illustrates a second embodiment of the invention, which is similar 
to that illustrated in FIG. 2, except that the second mechanism, which 
holds the rear portion 44 of the vehicle and pivots so that the vehicle 
can swing out into the flow stream 46, is supported in the cavity lower 
and upper walls 56,58, rather than through the transfer tube 14. In this 
embodiment, the vehicle 16 is pushed through the tube 14 into the first 
and second clamps 60,62 during arming. The clamps 60,62 can take any 
convenient form, but in the illustrated embodiment, the first, forward 
clamp 60 has upper and lower clamp pads 64,66 which can be urged toward 
and away from the vehicle 16 by respective hydraulic or pneumatic 
cylinders 68,70. The mechanism 60 can be moved transversely to the 
longitudinal axis of the cavity. The mechanical action of this first clamp 
mechanism 60 is, first, a movement outboard, thereby swinging the torpedo 
nose 26 outside into the flow stream, and then a release of the pads 64,67 
by retraction away from the torpedo 16. 
The second clamping mechanism 62 also has two types of action, the first 
being a pivoting about axis 72, to accommodate the swinging of the nose 
26, and the second being a retraction of pads 74, 76 similar to the second 
action of the first mechanism 60. In a simplification, the second 
mechanism 62 could be in the form of a ring or the like, which acts as a 
passive pivoting guide rather than a true clamp. In this variation, the 
movement pattern would merely be a pivot of the ring from a first 
position, for receiving and supporting the vehicle longitudinally along 
the cavity axis, through a limited pivot which reacts to the positive 
outboard displacement of the nose 26 by the first mechanism 60. 
With either variation of the second embodiment shown in FIG. 3, once the 
nose 26 is outboard of the cavity and influenced by the flow stream, the 
vehicle is launched under its own power, or solely by the outboard force 
exerted by the flow stream 46 acting on the inboard side of the vehicle. 
FIGS. 4(a) and 4(b) illustrate a third embodiment, which is similar to the 
first embodiment, in that the second support mechanism is the ram 40 with 
pivot joint 48 supported in the tube 14, but is different from the first 
embodiment with respect to the manner in which the nose 26 of the vehicle 
is moved in the outboard direction. In the third embodiment, the function 
of moving the nose 26 outboard, is provided by a submerged flow channel 
24, having a high recovery inlet 78 on the hull surface upstream of the 
cavity 18, and a discharge 80 into the cavity at a position between the 
cavity wall and the nose 26 of the supported vehicle. The first support 
and release mechanism 82 is therefore passive, rather than active. For 
example, the overall configuration of the first mechanism 82 can be 
generally similar to the mechanism 60 shown with respect to the second 
embodiment (FIG. 3(b)), except that the pads 64 or guides can merely be 
spring-loaded with a bias that is relatively light, so that the action of 
the inboard flow through the channel 24, overcomes the spring bias and 
pivots the torpedo 16 outwardly. Two such clamps 82, 90 may optionally be 
provided. FIG. 4(b) shows the preferred details of the inlet ramp 78, 
having sharp edges 84 which create vortices 86 in the diverted flow 88, 
and capture the momentum and pressure from the flow over the hull. 
FIG. 5 illustrates a fourth embodiment of the invention, with a passive 
first mechanism 92 and a channel 78 that cooperates with the first 
mechanism for urging the front portion of the torpedo laterally away from 
the hull, in a manner similar to the corresponding features of the third 
embodiment. The second mechanism 94, connected between the cavity wall and 
the back portion of the torpedo, is, however, a passive version of 
mechanism 62 shown in FIG. 3 for the second embodiment of the invention. 
In another embodiment best understood with reference to FIGS. 4(a) and 5, 
the torpedo may be prepositioned in the clamps 82, 90 or 92, 94 and stowed 
in the cavity recess 18 while the submarine is in port, thus eliminating 
the need for a torpedo or transfer tube 14. To initiate launch, the 
forward passive clamps are released, giving the torpedo freedom to rotate 
in a plane passing through the pivot joint 48 or pivot axis 96. The 
outboard rotational motion of the torpedo is initiated from flow and 
pressure developed from the high recovery inlet and channel 78. 
It should be appreciated that one of ordinary skill in the art can readily 
optimize the performance of the various mechanisms for implementing the 
invention as described generally above. For example, springs can be 
appropriately utilized for providing a biasing of the passive mechanisms 
toward the preload, or longitudinal support, position. This biasing would 
be appropriate, for example, for the pivot 48 in the ram 40 in the first 
and third embodiment shown in FIG. 2 and 4, respectively, and for the 
passive pivot guides 62 and 94 of the second and fourth embodiments, shown 
in FIGS. 3 and 5, respectively. Similarly, various combinations of passive 
and active mechanisms can be utilized for optimizing the performance in 
terms of variables such as reliability, speed of operation, minimization 
of noise, weight, occupied volume, and suitability for retrofitting onto 
existing hulls.