Deployment and retrieval methods for AUVs

1. A submersible device for deploying or retrieving autonomous underwater vehicles (AUVs), the submersible device comprising:

two or more platforms arranged in a stack, wherein each platform is configured to carry two or more of the AUVs;

a port; and

a transfer mechanism comprising a transfer device arranged to load or unload the AUVs onto or from the platforms, and an actuator arranged to move the transfer device between the platforms and the port in order to transfer the AUVs between the platforms and the port.

2. The submersible device of claim 1 , wherein the submersible device is for deploying the AUVs, the port is a deployment port, the transfer device is arranged to unload the AUVs from the platforms, and the actuator is arranged to move the transfer device in order to transfer the AUVs from the platforms to the deployment port during deployment of the AUVs.

3. The submersible device of claim 2 , wherein the deployment port comprises a deployment channel which is open at both ends so that during deployment of the AUVs a flow of water passes through the deployment channel, and the actuator is arranged to move the transfer device in order to transfer the AUVs from the platforms to the deployment channel during deployment of the AUVs.

4. The submersible device of claim 2 , wherein the submersible device is for deploying and retrieving the AUVs, the submersible device further comprises a retrieval port, the transfer device is arranged to load the AUVs onto the platforms, and the actuator is arranged to move the transfer device in order to transfer the AUVs from the retrieval port to the platforms during retrieval of the AUVs.

5. The submersible device of claim 1 , wherein the submersible device is for retrieving the AUVs, the port is a retrieval port, the transfer device is arranged to load the AUVs onto the platforms, and the actuator is arranged to move the transfer device in order to transfer the AUVs from the retrieval port to the platforms during retrieval of the AUVs.

6. The submersible device of claim 4 , further comprising one or more homing devices arranged to output homing signals which can guide the AUVs to the retrieval port during the retrieval of the AUVs.

7. The submersible device of claim 1 , further comprising a chassis, wherein the platforms are movably mounted to the chassis.

8. The submersible device of claim 1 , further comprising a chassis, wherein the platforms are rotatably mounted to the chassis so that the platforms can be rotated about a common axis relative to the chassis.

9. The submersible device of claim 8 wherein a first set of the platforms are arranged in a first stack and rotatably mounted to the chassis so that the first set of platforms can be rotated about a first common axis relative to the chassis, and a second set of the platforms are arranged in a second stack and rotatably mounted to the chassis so that the second set of platforms can be rotated about a second common axis relative to the chassis.

10. The submersible device of claim 1 , further comprising a chassis, wherein the platforms are integrated into a pallet which is removably mounted to the chassis so that the pallet can be removed from the chassis with the pallet carrying the AUVs.

11. The submersible device of claim 1 , wherein the port comprises a funnel.

12. The submersible device of claim 1 , wherein the transfer device is arranged to support an AUV with a support member underneath the AUV, by an action selected from a group consisting of: gripping sides of the AUV with a pair of gripping jaws, action of a vacuum, and action of a magnetic field.

13. The submersible device of claim 12 wherein the transfer device is arranged to support an AUV by gripping the AUV between a lower jaw underneath the AUV and an upper jaw above the AUV.

14. A method of deploying autonomous underwater vehicles (AUVs) with a deployment device, the deployment device comprising two or more platforms arranged in a stack, each platform carrying two or more of the AUVs, and a deployment port, the method comprising:

submerging the deployment device; and

after the deployment device has been submerged,

unloading the AUVs from the platforms with a transfer device;

moving the transfer device between the platforms and the deployment port in order to transfer the AUVs from the platforms to the deployment port; and

deploying the AUVs from the deployment port.

15. The method of claim 14 , wherein the submerging step comprises submerging the deployment device with the platforms carrying the AUVs.

16. The method of claim 14 , wherein the AUVs are unloaded one-by-one by the transfer device from the platforms, moved one-by-one by the transfer device from the platforms to the deployment port, and deployed one-by-one from the deployment port.

17. A method of retrieving autonomous underwater vehicles (AUVs) with a submerged retrieval device, the submerged retrieval device comprising two or more platforms arranged in a stack, a transfer device, and a retrieval port, the method comprising:

receiving the AUVs at the retrieval port;

moving the transfer device between the retrieval port and the platforms in order to transfer the AUVs from the retrieval port to the platforms; and

loading the AUVs from the transfer device onto the platforms so that each platform carries two or more of the AUVs.

18. The method of claim 17 further comprising after the AUVs have been unloaded from the transfer device onto the platforms, lifting the submerged retrieval device out of the water with the platforms carrying the AUVs.

19. The method of claim 17 , wherein the AUVs are received one-by-one at the retrieval port, moved one-by-one by the transfer device from the deployment port to the platforms, and loaded one-by-one by the transfer device onto the platforms.

20. The method of claim 14 , further comprising towing the submerged deployment device with a surface vessel as the AUVs are deployed.