Underwater Force Multipliers

Saab's AUV62 MR
Saab's AUV62 MR is a modular torpedo-shaped UUV designed for MCM missions that can be launched from a submarine via a standard torpedo tube or a MMP.

Published in the September/October 2020 Issue – Submarine-launched unmanned platforms are looking to covertly penetrate hostile A2/AD areas where their ‘mother ships’ fear to go.

In February 2020, Chinese government sources announced the recovery of the underwater drones China deployed in the Indian Ocean for the purpose of gathering oceanography data. Further east, while Chinese fishermen regularly report finding foreign underwater drones – ‘spies’ – in Chinese waters, China is rumoured to be working on the development of an underwater Great Wall; a seabed of sensors protecting key strategic points on its shores. Further north, Russia has been developing the Poseidon, a submarine-launched underwater nuclear-warhead delivery platform.

Evidently, the race for underwater strategic and tactical superiority is on. As noted by Andrew Davies and James Mug, in a Strategic Insight from the Australian Strategic Policy Institute (ASPI), The next big grey thing – choosing Australias future frigate, “the enormousness of the ocean makes it one of the few remaining areas on Earth where big military platforms, such as ballistic missile submarines, can hide. Despite the development of new detection technologies, the ocean remains mostly opaque at depths of just a few dozen meters.” In such context, unmanned vehicles (UV) are key strategic capabilities for carrying out a number of missions without endangering valuable platforms. When launched from a submarine, they represent a great force multiplier.

Beyond Opacity

The opacity of oceans and seas is the result of a wide variety of factors. Chiefly amongst those are the levels of salinity, the topography of sea and ocean beds, and the traffic encountered in those waters, whether military or civilian. All these characteristics vary greatly across the world’s oceans and seas, presenting significant challenges for noise propagation and recognition, and requiring in-depth knowledge of the areas of operation in order to plan missions, assets and payloads accordingly.

In such context, any strategic advantage will go to navies capable of using these challenging characteristics to their advantage. Guarding power projection assets, such as aircraft carriers and amphibious vessels, from adversary underwater assets may be difficult in these environments, yet such difficulties can be contrasted by acquiring the systems that can carry a number of missions autonomously, keeping key capabilities and crew out of harm’s way.

Until recently submarines were the platforms of choice, using this ‘underwater fog of war’ to a navy’s advantage. Stealthy and built to undertake long range missions over sustained periods of time, they can gather significant volumes of data or deliver weapons while remaining undetected. However, the resurgence of Great Power competition over the past few years has brought about increasing concerns over the development of Anti-Access/Area Denial (A2/AD) strategies and their threat to such costly capabilities.

According to the document Advancing Autonomous Systems: An Analysis of Current and Future Technology for Unmanned Maritime Vehicles, published by the RAND Corporation in 2019, “the layers of sensors and overlapping weapon rings create multiple opportunities for adversaries to attack detectable platforms; in the most challenging A2/AD environments, targeted platforms are unlikely to survive, even with advanced kinetic interception capabilities.” The development of UVs these past few years is a direct response of submarines’ vulnerability to such A2/AD tactics.

Unmanned Tactics

Unmanned – or autonomous – vehicles have been gaining significant traction in the military domain over the last decade because they can be used to carry out missions that would otherwise put human lives and key capabilities at risk.

Until recently, in the underwater domain, this had been particularly evident in relation to mine hunting. Slowly fallen into oblivion after the end of World War II (WWII), mines have made a strong comeback in the past decade with the development of smart mines as part of A2/AD strategies. This has led an increasing number of nations choosing to pair Unmanned Underwater Vehicles (UUVs) with a mother ship to carry out Mine Counter Measure (MCM) missions. Although the vast majority of MCM systems are launched from surface ships, a number of countries, especially the US, are exploring the possibility of launching them from submarines as well.

But the real, emerging, tactical advantage of submarine-launched UUVs resides in their ability to offer a more extended and safer range for power projection into chokepoints and contested space. Johan Strandlund, head of marketing and sales Underwater Systems, Saab, told AMR that, “UUV operations from submarines not only give the advantage of enhanced ISR (sensor multiplying capability) with a higher degree of covertness (both on a strategic and tactical level) but also a greater stand-off between the submarine and the area of operations.”

Key to overcoming A2/AD barriers is the ability to gather the data necessary to build as complete a situational awareness picture as possible. As noted in the June 2020 report published by the Stockholm International Peace Research Institute (SIPRI), Artificial Intelligence, Strategic Stability, and Nuclear Risk, “machine learning and autonomy hold major promise for early warning and ISR.” These two technologies – supported by a variety of navigation, sensor and communication payloads – enable the collection and processing of large volumes of data on-board, allowing UUVs to not only identify by themselves signals, objects and situations of interest for the purpose of ISR, but also to safely navigate autonomously over extended ranges and periods of time. These systems can either work in collaboration with other UUVs or may be used as single-system UVs.

Networked UVs

“Multiple small platforms distributed across a wide area could help provide broader sensor coverage and would not require more than limited relocation,” notes the RAND report. This would not only allow them to work together as a buoy field or deployable underwater sonar array, it would also make them less vulnerable to individual countermeasures.

Shaped like torpedoes, to facilitate launching from the submarine’s torpedo tubes, UVs working as a part of a network of ISR manned/unmanned systems carry out their programmed mission autonomously from the mother ship. How the data they collect is then shared and used may vary according to different CONOPS. It can be shared rapidly with a surface or air asset for immediate action in the context of early warning. Alternatively, it can be shared with other unmanned platforms – whether underwater, surface and/or air – to then be retrieved by the submarine itself or other manned platforms to plan for future action.

The US Navy (USN) has been experimenting with this CONOPS for the past few years. According to the Congressional Research Service report, Navy Large Unmanned Surface and Undersea Vehicles: Background and Issues for Congress, published in March 2020, the USN is pursuing such capabilities to meet emerging military challenges, “particularly from China.” The USN vision includes extra large platforms, which are pier launched, as well as large, medium and small systems that can be surface or submarine launched.

AeroVironment, specialised in small unmanned air systems (UAS) and loitering missiles, has been working with the USN to develop its Blackwing project. A small UAS delivering rapid-response ISR, a company spokesperson told AMR in a written statement, the Blackwing “can be deployed from an underwater submarine using an underwater-to-air delivery canister.” It incorporates an advanced Electro-Optical and Infrared (EO/IR) sensor and provides operators with real-time video for information gathering and feature/object recognition. It can relay information to other UUVs via DDL-Joint, interoperable, encrypted wide-band. Conceptualised during the USN Submarine Over the Horizon Organic Capabilities project, “the Blackwing transitioned to USN submarines in 2016.”

A small UAS delivering rapid-response ISR, AeroVironment’s Blackwing can be deployed from a submarine using underwater-to-air delivery canisters.

The role of the submarine in these case scenarios, however, remains limited. Technological advances have made significant strides in recent years to improve range and autonomy, but underwater communication remains challenging. Not only do ocean and sea characteristics considerably limit communication frequencies, but the necessity for a submarine to remain undetected also constrains communications with other platforms to a minimum. Unless the submarine is already at periscope depth, which is unlikely to be the case in an A2/AD environment.

Single-System UUVs

Submarine-launched UVs may also be used as single platforms to undertake ISR missions. In this scenario, Unmanned Underwater Vehicles (UUVs) are launched from the submarine to carry out specific ISR missions in complete autonomy and are subsequently recovered to allow data processing onboard.

UUV systems vision
The USN has developed a UUV systems vision that encompasses a wide range of unmanned systems considerably extended the range and capabilities of its submarines.

“Recovery is the main issue for submarine-launched UUVs,” Cyril Levy, Head of Unmanned Systems & Mine Warfare at Naval Group told AMR. “On a surface ship there will always be crew-members assigned to assist with the recovery of a returning UV, but this is not possible on a submerged submarine.” A submarine, which is in movement most of the time, creates turbulences around its shell that make it particularly difficult for UUVs to fit back into the tube without endangering the submarine according to Levy.

As such, Naval Group has been working to develop a docking station that can be fitted onto a submarine and can safely host the UUV. The docking station is complete with an automatic charging system working with induction technologies and a special liquid that allows for long-term storage of the UUV, thus avoiding corrosion from seawater. The large volumes of data collected during the mission are transferred from the UUV to the submarine via the submarine’s secure Wi-Fi system, then transformed in the correct format to be processed and analysed via the submarine’s Combat Management System (CMS).

Naval Group has also developed the D19, a torpedo-shaped UUV weighting approximately one tonne and between six and eight metres-long – depending on the number of batteries fitted to increase autonomy. “The engine of the system has also been designed to ensure stability at very low speed,” added Levy.

Similarly, Saab Kockums’ latest submarine design, the A26, features a Multimission Portal (MMP). Initially developed for the delivery of Special Forces divers, the MMP design takes into consideration “the various needs for operating a UUV, both in terms of ensuring the necessary space and handling considerations inside the vessel, and the MMP itself to ensure safe and quiet operation in the confines of a submarine,” Benoit Passard, Kockums executive, told AMR.

Kockums’ A26 submarine
Kockums’ A26 submarine design includes a MMP originally designed for special forces diver delivery that can also launch a UUV.

Additionally, all Saab’s Remotely Operated Vehicles (ROV) and UUVs can be launched from a submarine as long as there is space on-board. More specifically designed for these operations are the SUBROV, a small ROV for general underwater operations tethered to the submarine by a fibre optic cable, and the AUV62 MR, a modular torpedo-shaped UUV designed for MCM missions. “Both systems are launched and retrieved from a standard torpedo tube and the Swedish armed forces have been operating both systems for years,” Strandlund told AMR, although in the future the AUV62 MR will also be launched from the MMP.

Saab’s SUBROV is a small ROV for general underwater operations tethered to the submarine by a fibre optic cable, which can be launched via a standard torpedo tube.


UVs have been in development for quite some time across different branches of the armed forces around the world. Yet, in the naval domain, it is the increase in A2/AD strategies brought about by the resurgence of Great Power competition that has triggered a race in the development of these force multipliers. Whether they are employed for MCM or ISR missions, UVs provide submarines with a significantly extended range to facilitate power projection in denied environments.

However, despite great technological strides, a number of challenges remain. “One of the greatest issues for the future is the ability to continue developing the autonomy of these systems,” Levy told AMR. Autonomy not only in terms of being able to interact intelligently with the environment they operate in, through artificial intelligence, but also through high performance batteries that can continue extending their ranges. “Increased intelligence also means increased need for communications,” noted Levy, and if the industry succeeds in overcoming some of the constraints of communicating underwater, then these systems will have truly become untethered.

by Dr. Alex Valenti