CAPABILITY OF A SUBMARINE

Field of the Invention

The present invention relates to submarines and more particularly to submarines capable of deploying and recovering operational means such as unmanned underwater vehicles (UUVs) or Special Operations Forces (SOFs) .

Background of the Invention

The use of submarines as platforms for deployment and recovery of operational means such as those mentioned above particularly for intelligence and combat missions is becoming increasingly important in recent decades.

This trend has been driven by the emergence of UUVs of different typologies and, in fact, several proposals for the incorporation of UUVs in submarines are known in the prior art.

One of the approaches used in the prior art is based on modifying the structure of the submarine to allow the external incorporation of UUVs either externally, such as the system for fixing one or more unmanned, hydrodynamically shaped, autonomous, undersea platforms to the bow of a submarine described in US 5, 964, 175 or by providing a stowage unit for a payload such as a weapon, countermeasure or an unmanned underwater vehicle (UUV) and a method for using the unit to deploy the payload as described in US 2011/083600.

Another approach used in the prior art is the use of a torpedo tube for deployment and recovery of UUVs. An example of this is described in US 7,798,086.

None of these proposals allow conventional submarines to expand their operational capability by using UUVs without substantial changes in their design.

On the other hand, the capability of conventional submarines as platforms for deploying and recovering SOFs is limited by their low evacuation capacity which prevents, for example, the simultaneous deployment of a command of six divers.

The present invention is aimed at solving these drawbacks. Summary of the Invention

An object of this invention is to provide a dry shelter that can be mounted on a submarine not prepared to carry out missions that require UUVs or SOFs allowing it to take over said missions without affecting its search and rescue capabilities.

In the context of the invention, a dry shelter is understood as a non-floodable shelter allowing the operation of deploying and recovering unmanned underwater vehicles (UUVs) and military personnel such as the Special Operations Forces (SOFs), for example. Likewise, a dry space will be understood as the non-floodable shelter space itself which allows said operations.

These and other objects are achieved by means of a dry shelter that can be mounted on the outer surface of a submarine according to claim 1 and a submarine according to claim 12. The dependent claims define the preferred embodiments of the invention .

Specifically, in a first inventive aspect the dry shelter that can be mounted on the outer surface of a submarine comprises :

a) a watertight compartment;

b) an operational chamber arranged inside said watertight compartment, comprising a first access path to/from the outside, to deploy/recover to/from the outside an operational means through said first access path to/ from the outside when the submarine is submerged;

c) a compensation tank for storing water having a volume slightly larger than the volume of said operation chamber, arranged inside said watertight compartment and in fluid communication with the operational chamber; and

d) flooding and draining means for flooding said operational chamber with water stored in the compensation tank so that said operational means can be deployed/ recovered through said first access path to/from the outside and for draining water from said operational chamber to said compensation tank to allow accommodating said operational means in a dry space.

The compensation tank for storing water has a volume slightly larger than the volume of said operation chamber to allow compensating the volumes released during deployment operations and due to losses in the processes of flooding and draining the operational and compensation chambers .

In an embodiment of the invention, the watertight compartment comprises submarine attachment/fixing means, preferably a supportive attachment structure.

In an embodiment of the invention, the watertight compartment is configured with the sufficient volume for conferring the self-compensating characteristic and so that it can be mounted to avoid a weight penalty on the submarine. A dry shelter that can be mounted on conventional submarines without posing trimming problems to the submarine is therefore achieved.

In an embodiment of the invention, said watertight compartment and said operational chamber are configured in the shape of dome-ended elongated cylinders . In another embodiment of the invention, the watertight compartment and the operational chamber are so arranged that their longitudinal axes are parallel to the longitudinal axis of the submarine when they are coupled thereto. A dry shelter with a suitable configuration to be mounted on the outside of a submarine, particularly aft of the sail, is therefore achieved.

The operational chamber should preferably have a length greater than 5m and an inner diameter greater than 1.6m.

In an embodiment of the invention, said operational chamber and said compensation tank are arranged inside said watertight compartment in a position in which their centers of gravity are located below the center of gravity of said watertight compartment. A dry shelter that can be mounted on submarines minimizing the moments transmitted to the submarine is therefore achieved.

In an embodiment of the invention, said flooding and draining means comprise:

a piping system between the operational chamber and the compensation tank controlled by a flood and drain valve;

a device for injecting compressed air into the compensation tank and the operational chamber to perform said flooding and draining operations;

a ventilation device for discharging air from the operational chamber and the compensation tank when they are filled with water;

a device for equalizing the pressures in the operational chamber with respect to the outside to allow the opening of the first access path to/from the outside.

In an embodiment of the invention, the flooding and draining means are controlled from inside the operational chamber. In another embodiment, the flooding and draining means are controlled from inside the submarine.

Said operational means is advantageously a UUV. A mono- functional dry shelter is therefore achieved.

In an embodiment of the invention, the dry shelter also comprises an access path to/from the submarine, preferably provided with a hatch, so that the dry shelter can be mounted on the submarine in a position which allows connecting that access path with an escape chamber of the submarine to allow the entry/exit of an operational means to/from the dry shelter.

Advantageously with said access path to/from the submarine, said operational means is a UUV and/or a commando of SOFs, i.e., the deployment and retrieval of the UUVs and/or a commando of SOFs is facilitated. A multi-functional dry shelter for UUVs and/or SOFs is therefore achieved.

In an embodiment of the invention, the dry shelter also comprises a second access path to/from the outside, preferably provided with a hatch, on the upper surface of the dry shelter so that the dry shelter can be coupled to a search and rescue vehicle for performing escape operations. A dry shelter that can be used both for operational missions, such as intelligence missions or combat missions, and for escape operations of the submarine crew is therefore achieved.

In another inventive aspect, the above-mentioned objects are achieved with a submarine having the dry shelter of the first inventive aspect mounted on its outer surface. In an embodiment of the invention, the access path to/from the submarine is coupled to an escape hatch of the submarine.

The immersion displacement of the dry shelter should preferably be less than 5% of the immersion displacement of the submarine .

All the features described in this specification (including the claims, description and drawings) can be combined in any combination except for combinations having such mutually exclusive features.

Brief Description of the Drawings

Other features and advantages of the present invention will be inferred from the following detailed description of an illustrative and non-limiting embodiment describing the object thereof in relation to the attached figures.

Figures la and lb are schematic cross-section and plan views, respectively, of a dry shelter according to the present invention .

Figures 2a, 2b and 2c are schematic cross-section views of a dry shelter according to the present invention in three different stages of the process of deploying an operational means .

Figures 3a and 3b are schematic cross-section views of a dry shelter according to the present invention including the means used for flooding and draining the operational chamber illustrating its operation in each case.

Detailed Description of the Invention

The main components of a dry shelter 10 mounted on the outer surface of a submarine 12 according to a preferred embodiment of the present invention, shown in Figures la and lb are the following:

- A watertight compartment 11 having an elongated dome- ended cylinder shape with its axis arranged parallel to the longitudinal axis of the submarine.

- An operational chamber 13 having an elongated dome-ended cylinder shape with its axis arranged parallel to the longitudinal axis of the submarine with a first access path to/from the outside 21 in a lateral end of the dry shelter 10, a second access path to/from the outside 25 on the upper surface of the dry shelter 10, and an access path to/from the submarine 23 on the lower surface of the dry shelter 10.

- A compensation tank 15.

- A supportive attachment structure 19 for attachment to the submarine 12.

The operational chamber 13 is used to deploy/recover an UUV or a commando of SOFs (not shown) through the first access path to/from the outside 21. The access path to/from the submarine 23 allows the movement of members of the commando of SOFs from the submarine to the operational chamber 13 and vice versa. On the other hand, the second access path to/from the outside 25 provides for the communication with a search and rescue submarine vehicle and the carrying out of escape operations .

The compensation tank 15 is used as a storage means for storing the water needed to flood the operational chamber 13 when a UUV or a commando of SOFs is deployed through the first access path to/from the outside 21. The compensation tank 15 has an external valve 31 to take in/drain water from the outside/inside. The compensation tank 15 must have a volume slightly larger than the volume of the operational chamber 13 for allowing the performance of several missions without using the external valve 31 for expelling water to the outside to prevent the production of signals indicating the presence of the submarine in the mission area.

The operational chamber 13 and the compensation tank 15 are internally fixed to the watertight compartment 11 which has the volume needed so that the buoyancy given by the dry shelter 10 when it is mounted on a submerged submarine compensates its total weight. This implies that inside the watertight compartment 11 there is an empty inner space that is not occupied by the operational chamber 13 and the compensation tank 15.

A UUV or a commando of SOFs would be deployed in the following the steps.

In the first step (see Figure 2a) the UUV or the commando of SOFs is located in the operational chamber 13 which is in a dry state, and the compensation tank 15 is full of water. The commando of SOFs in turn would have reached the operational chamber 13 from inside the submarine through the access path 23 which is closed afterwards. In this step only the watertight compartment 11 is subjected to external pressure.

In the next step (see Figure 2b) the operational chamber 13 is flooded with the water from the compensation tank 15. In this step only the watertight compartment 11 is subjected to external pressure. Figure 2b shows the compensation tank 15 completely empty for illustrative purposes but in fact the compensation tank 15 could contain a volume of water equivalent to the volume displaced by the UUV or the commando of SOFs present in the operational chamber 13.

In the third step (see Figure 2c) the pressures in the operational chamber 13 are equalized with the outside and the first access path to/from the outside 21 is opened allowing the deployment of the UUV or the commando of SOFs. In this step, both the watertight compartment 11 and the operational chamber 13 are subjected to external pressure.

The UUV or commando of SOFs would be recovered in following steps:

In the first step, with the operational chamber 13 full of water, the first access path to/from the outside 21 would be opened allowing the entry of the UUV or the SOFs command.

In the second step, the first access path to/from the outside 21 would be closed and the water from the operational chamber 13 would be drained to the compensation tank 15.

In the third step, the operational chamber 13 would be in such a dry state that the access path to/from the submarine 23 could be opened.

The dry shelter 10 object of the present invention allows using different types of UUVs which may or may not require the operational chamber 13 to have specific means for their deployment and recovery which would be incorporated thereto if applicable. A detailed description of said specific means is not necessary for the purposes of the present invention.

As shown in Figures 3a and 3b the operational chamber 13 comprises:

- A flood and drain valve 33 which allows controlling the water flow from the compensation tank 15 to the operational chamber 13 and vice versa.

A device for injecting compressed air into the compensation tank 15 or into the operational chamber 13 to carry out said flooding or draining operations comprising a pipe 41 fed by compressed air bottles 43 and controlled by a feeding valve 45 and a three-way distribution valve 47 that allows directing the compressed air to the upper part of the compensation tank 15 or to the upper part of the operational chamber 13.

A ventilation device for discharging air from the operational chamber 13 or from the compensation tank 15 when it is filled with water comprising a pipe 51 with inlet ports in the operational chamber 13 and in the compensation tank 15 that leads the discharged air to a vent valve 57 under the control of a three-way distribution valve 53. A sight glass 55 allows observing the air/water flowing through the pipe 51.

- A device for equalizing pressures with respect to the outside including an equalizing valve 61.

With these means, the flooding of the operational chamber 13 is carried out as follows:

The three-way distribution valve 47 must be in a position that allows blowing into the compensation tank 15 and the three-way distribution valve 53 must be in a position that allows discharging the air from the operational chamber 13.

- The vent valve 57 is opened.

- The flood and drain valve 33 is opened.

- The feeding valve 45 is opened and the air provided by the air bottles 43 is directed to the compensation tank 15 by means of the distribution valve 47. - The air pushes the water of the compensation tank 15 towards the operational chamber 13 through the flood and drain valve 33.

- As the water fills the operational chamber 13, air is discharged by using the mentioned ventilation device.

- When the operational chamber 13 is flooded (which can be detected through the sight glass 55 due to the presence of water flowing through pipe 51) the vent valve 57, the feeding valve 45 and the flood and drain valve 33 can be closed.

- Pressures are equalized with the outside by opening the equalizing valve 61 and the operational chamber 13 is ready to proceed with the opening of the first access path to/from the outside 21.

On the other hand, the drainage of the operational chamber 13 is carried out as follows:

The three-way distribution valve 47 must be in a position that allows blowing into the operational chamber 13 and the three-way distribution valve 53 must be in a position that allows discharging the air from the compensation tank 15.

- The vent valve 57 is opened, the equalizing valve 61 being closed.

- The flood and drain valve 33 is opened.

- The feeding valve 45 is opened and the air provided by the air bottles 43 is directed to the operational chamber 13 by means of the distribution valve 47.

- The air pushes the water of the operational chamber 13 towards the compensation tank 15 through the flood and drain valve 33.

- As the water fills the compensation tank 15, air is discharged by using the mentioned ventilation device.

- When the operational chamber 13 is empty (which can be detected through the sight glass 55 due to the presence of water flowing through pipe 51) the vent valve 57, the feeding valve 45 and the flood and drain valve 33 can be closed.

The second access path to/from the outside 25 in the upper part of the dry shelter 10 allows carrying out, in addition to the missions carried out by a UUV or a SOFs command, search and rescue missions by means of a search and rescue submarine vehicle which could be coupled to the dry shelter 10. The operational chamber 13 allows speeding up the transfer of the crew from the submarine to the search and rescue submarine vehicle .

As mentioned above, the invention also comprises embodiments in which the dry shelter 10 only includes the first access path to/from the outside 21 for performing missions with only UUVs . In this case, the flooding and draining means would be remotely controlled and commanded from the submarine.

The watertight compartment 11 and the operational chamber 13 must have the same resistant capacity as the submarine, i.e., it must be resistant to the same operating depth as the submarine. Advantageously, the operational chamber 13 must be resistant to the depth foreseen for said operational missions and/or for said escape missions, which can be different from that of the submarine. In this respect it is envisaged that the UUVs can be deployed at any depth. The commando of SOFs is obviously deployed at lower depths.

The total weight of the dry shelter 10 with all the water needed for its operation is compensated by the buoyancy provided by the volume of the watertight compartment 11 thereby not creating any stability, floatability or trimming problems to the submarine which, as mentioned, is comparatively much longer in length and width.

The moments caused by the additional weight of the UUV or a commando of SOFs can be readily absorbed by the submarine trimming system. The weight change experienced by the dry shelter 10 during deployment or recovery operations has little effect on the equilibrium condition of the submarine and in any case can be corrected by the compensation and trimming systems of the submarine.

The influence of flooding and draining operations of the operational chamber 13 on the longitudinal trimming of the submarine depends on the displacements in length. Since the displacements from the compensation tank 15 to the operational chamber 13 and vice versa are relatively small it can be considered that they have virtually no effect on the longitudinal trimming of the submarine.

In long-term transits on surface or on a rough sea it is advisable to empty the compensation tank 15 to reduce the high weights as much as possible.

In conventional submarines, the dry shelter 10 must be mounted on where the escape chamber is located. For those conventional submarines that have the escape chamber located aft of the sail, the first access path to/from the outside 21 will be located in the aft end of the dry shelter.

It is considered that the minimum inner dimensions of a cylindrical operational chamber 13 for performing the above- mentioned missions must be of a length of 5m and an inner diameter of 1.6 m and that the immersion displacement of the dry shelter must be less than 5% of the immersion displacement of the submarine to prevent trimming problems .

In nuclear submarines, the dry shelter can be mounted fore or aft of the sail depending on the location of the escape chambers. From a hydrodynamic point of view, both locations will demand the dry shelter to incorporate suitable fairings to improve its hydrodynamic performance.

The main advantages of the invention over the prior art are the following:

- The dry shelter 10 according to the invention is a self- compensating system. It can be operated independently of the regulation, compensation and trimming systems of the submarine on which it is mounted. When submerged, its design, per se, compensates the weight of the entire system and does not alter the submarine' s own equilibrium condition when submerged.

The dry shelter 10 is a self-contained system. The location of the operational chamber 13 inside the watertight compartment 11 optimizes its integration level making its installation viable in a very high percentage of conventional submarines having an escape chamber. - The dry shelter 10 is a modular solution external to the submarine's resistant hull. It is therefore adaptable to any conventional submarine having an escape chamber without affecting its original design. The minimization of the necessary interfaces with the submarine systems provides for a high degree of modularity.