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Tactical Diving Underwater Manoeuvre - The Future Direction of Travel

Changing Operational Landscape

All areas of the military require to continually evolve in order to meet current and future operational requirements. Defence diving is no exception and geopolitical tensions and increasingly sophisticated threats are currently driving changes to maritime doctrine and operational concepts of operation. At a tactical level, the recovery of a sunken river bridging system or battle damage ship repairs at sea cannot be accomplished by machine alone. As a consequence, the need for a manned intervention underwater engineering capability by both armies and navies will remain. However, in the field of naval Mine Countermeasures (MCM) diving, significant effort is being made to remove the ‘man’ from the minefield by substituting the human with a Remotely Operated Vehicle (ROV) or Autonomous Underwater Vehicle (AUV). As a consequence, the number of specialist MCM divers is predicted to decline and manned MCM ‘clearance diving’ will in the main, likely be restricted in the future to ‘shallow’ waters.

With a focus on land operations for the last two-decades, maintaining and developing a maritime Special Operations Forces (SOF) capability has not been the priority of most ‘Western’ nations. However, a changing geopolitical landscape has initiated a maritime pivot and numerous nations and military alliances are currently re-structuring their defence forces accordingly. Both ‘blue water’ and littoral maritime activity will therefore increase globally, which will include the expansion of maritime SOF activity.

Modernisation Priorities

Land based operational activity has dominated for the last twenty-years leaving maritime SOF with a number of maritime capability deficiencies. Modernisation priorities therefore include but are not limited to: (1) improved lethality & stand-off attack capability, (2) increased Underwater Manoeuvre (UWM) with greater range, speed and operational employment flexibility that offers an ‘organic’ unit level capability, (3) signature reduction, (4) increased sub-surface communications, (5) electro optical sensor systems able to detect, recognise, identify, range and track objects of interest, (6) improved sub-surface navigation precision, (7) diver thermal protection, (8) extended duration tactical life support systems with increased depth capability and duration, (9) integration of un-manned surface and sub-surface systems

into the SOF maritime battle space, (10) improved situational awareness above and below the water-line. Addressing these capability priorities is requiring significant defence investment and industry innovation. At the User level, whilst these technological challengers are being addressed, there is a transitional drive to re-install a maritime operations culture within ‘Western’ maritime SOF organisations.

A combat diver on the shore with fins and rebreather disembarking from a JFD torpedo seal

A tactical diver beaches the two-man JFD Torpedo Seal TDV during a training exercise.

Note the mast to enable periodic GNSS position fixing whilst the vehicle remains submerged

Operational Employment

If maritime SOF activity is predicted to expand, what then will operational tasking look like? Direct Action (DA) strategic asset neutralisation or aid to civil authorities such as Maritime Counter Terrorism (MCT) / Maritime Interdiction (MI) operations, will remain. However, an expansion of maritime capability is occurring by nations that have in the main been generally confined to ‘home waters’. This will stimulate an increase in tasking scenarios such as Intelligence, Surveillance, Target Acquisition and Reconnaissance (ISTAR) operations in support of multi-nation coalition forces. Such operations may for example include: (1) electronic intelligence, (2) stills and video imagery capture of critical infrastructure, geographical locations or persons of interest,

(3) target acquisition for remotely operated weapon delivery systems, (4) seabed sensor deployment in maritime navigation choke points, (5) stand-off attack, (6) deception and distraction, (7) psychological operations, (8) reconnaissance and attack drone deployment.

JFD Shadow Seal travelling on the waters surface

The JFD Shadow Seal electrically powered ‘hybrid’ TDV in surface mode is able to transport

four Operators discretely on the surface and covertly sub-surface over long distance

An Expanding Water Gap

Increasingly sophisticated land, seabed and airborne sensor / weapon systems are now able to reach further offshore, bolstering coastal defences. As a consequence, when facing peer or near peer adversaries, the viability of inserting a Tactical Diving Team (TDT) by small inflatable craft to within realistically achievable swimming distances of an objective is rapidly declining. In response, surface or sub-surface SOF insertion support platforms will require to remain further offshore to mitigate Anti Access Area Denial (A2/AD) weapon systems. Crossing the increasingly expanding littoral water gap discretely and covertly is therefore presenting a number of challenges to maritime SOF planners.

To extend the sub-surface range of a Tactical Diver, SOF will increasingly look at creating or expanding UWM capability. As a consequence, increasing use will be made of the Tactical Diving Vehicle (TDV). Whilst such means of transportation is not new, miniaturised precision navigation systems and rapidly evolving high power density battery technology is enabling increased TDV duration whilst reducing submersible craft weight and size. In addition, there will be a trend towards larger multi-man TDVs that can travel extended distances on the surface at high speed and when required, fully submerge for a covert infiltration / exfiltration or for threat evasion. Such craft are increasing in sophistication providing the ability to not only transport maritime SOF, but provide an ISTAR capability as well as serving as stand-off attack platforms, all of which will greatly enhance maritime SOF capability.

High speed surface mode of the JFD carrier Seal Tactical Diving Vehicle

Able to operate in surface, semi-submerged and submerged modes, the JFD Carrier Seal offers maritime SOF a high-speed extended

range over the horizon discreet and covert infiltration / exfiltration capability and stand-off attack / fire support platform

In addition to the manned TDV, increasing use will be made of automation and autonomy where TDVs in ‘self-drive’ mode can transport a TDT into the objective area and loiter offshore ready for pick-up. Additionally, an autonomous TDV can be deployed to deliver or recover a TDT or to re-supply Operators who remain deployed over extended periods near the sea land interface.

Free Swimming Limitations

The physiological limitations of a free-swimming TD are well understood by maritime SOF planners and it is increasingly understood that placing a small diving insertion surface support platform such as an inflatable craft, within realistically achievable swimming distances of an objective, can significantly increase the probability of mission compromise. Due to this risk, extending the infiltration swim distance can be considered, particularly if the threat level permits a period of surface swimming, however on completion, due to the significant physical effort required to complete such a mission, there is a notable reduction in human cognitive and physical performance and thus combat effectiveness. This is an important planning consideration as any diver pick-up point located close to shore, remains in an area of high threat potential.

Combat Diver under water using SeaCraft propulsion

A two-man SOF tactical diving team using a Seacraft lightweight twin diver propulsion

system with an operational range in excess of 15 nautical miles.

Extended periods of submergence require other human physiological limitations to be considered and planned for. For example, when using a 100% oxygen Tactical Diving (TD) Life Support System (LSS), due to oxygen toxicity considerations, as a general guide, the maximum single dive oxygen exposure is frequently restricted to four-hours. Dependent upon the time of year and the latitude, a swim / dive duration of up four-hours might consume all or most of the period of darkness, resulting in infiltration / exfiltration phases having to be conducted at dusk / dawn or worse case, in day-light, which is generally operationally unacceptable. As a consequence, any means of reducing the time spent sub-surface, particularly on or near the objective high threat zone, is highly desirable as this will compress the execution phase of the operation.

A Tiered Approach to Underwater Manoeuvre

To address the challenges of an expanding littoral ‘water gap’, the concept of a tiered capability will increasingly be applied to TD and UWM SOF projection. Such an

approach will for example include: (1) Operator worn propulsion, (2) single or two Operator TDVs, (3) multi-Operator free-flooding TDVs (single mode and multi-mode vehicles) and (4), one atmosphere ’dry’ vehicles. As a consequence, driven by mission objectives, threat levels and environmental / geographic conditions, maritime SOF will be required to move seamlessly between capability tiers in order to best exploit the tactical and strategic maritime landscape. Paul Haynes is the Head of Special Operations Capability for JFD and a former UK Special Forces diving Instructor, Supervisor and Swimmer Delivery Vehicle Operator. Since leaving the military, Paul has worked for JFD, the world’s largest manufacturer of defence diving equipment and as a consequence, remains at the forefront of special operations life support and submersible vehicle development, design, test and training (

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