The nuclear option: Thinking laterally to sustain the Royal Navy’s nuclear submarine capability

Submarines, particularly those powered by nuclear propulsion, sit at the pinnacle of technological sophistication in modern militaries, combining stealth with incredible lethality, silently prowling the depths and securing vast maritime spaces. But it is notoriously complex to maintain these machines and the crews that make them tick at sea; a challenge that is increasingly compounding for the UK’s fleet. The UK’s limited SSN (nuclear attack submarine) availability threatens the long-term retention of one of Britain’s most critical military capabilities. Despite the many daunting industrial and supply chain challenges that such a move could present, supplementing the current fleet with diesel-electric propulsion could be part of the answer to safeguarding the UK’s capacity to field a nuclear submarine fleet into the future.

First and foremost, the most crucial element of the complex ecosystem that puts a submarine to sea is the people factor. Quite aside from operational output, platform availability for submarines has a significant effect on people and their careers. Delays in completing maintenance periods means that boats’ programmes are often subject to significant and short notice change. The compound effect on boats over time has led to a run of record length patrols. The return of a Vanguard-class submarine recently from another patrol of over 200 days underscores the point. This state of affairs leads to frustration, anxiety and uncertainty for crews and their families, testing the resolve of otherwise resilient submariners.

But beyond the resilience challenges for our people, there is another people-related implication for this availability conundrum, which signals a more potent issue down the line. In terms of career development, submarines not being routinely available for service mean that personnel are gaining far less time operating their platform than has previously been the case. This is not a unique challenge to the Silent Service and has consequences across all branches and in every facet of the Service. Shortening sea experience means that, through no fault of their own, people are less likely to know ‘what good looks like’, and how the unintended negative consequence of apparent shortcuts can manifest.

Crews unable to train at sea do not develop the mental muscle memory borne of a library of experience. Experienced Royal Navy operators talk about a Commanding Officer’s sixth sense, that prickle of hair rising at the back of the neck. This is not a mystic gift conferred with rank, but the product of deep familiarity and repetition. As Malcolm Gladwell explains in Blink, it is the same phenomenon seen when a poker player instantly senses a bad hand, or when an athlete seems to know where a teammate will be without looking: the unconscious recognition of patterns we have encountered countless times before. The innate understanding of one’s circumstances and the almost imperceptible hazards around us in whatever situation we find ourselves, is lost when one does not possess the experience required to enable it. This is true across all ranks, rates and specialisations, from the young Officer of the Watch on the bridge in a busy shipping environment to the Weapons Electrical Engineer advising their CO whether or not the latest defect can be fixed or mitigated at sea safely. This deprivation of applied, at-sea experience diminishes the crew, top to bottom.

The Royal Navy has long prided itself, rightly, on having officers and ratings trained to high standards, and imbued with deep wells of experience to draw upon. Nelson may have been given his first command at 23 but by then he had been in the Navy for ten years, spending the majority of his time at sea. That tradition of prizing hard-won experience has meant that we are far less prescriptive in our doctrine than other Navies and services. It is what supports our philosophy of ‘Mission Command’. Rather than telling commanders or teams what to think, we have taught them how to think, how to make the best decision in the situation they find themselves in, fighting what they see rather than trying to lay out every decision for them. The system has been fed by deep wells of experience and robust training regimes. The former is running dry and, consequently, the latter is parched.

The Royal Navy has, for at least the last 40 years, consoled itself with the belief that whilst it may no longer be the biggest navy in the world, it is the best trained. Until recently there was probably a strong case to be made for that argument. But availability, or rather the lack of it, is challenging this core tenet. First-rate men and women continue to do their best to maintain standards across the Service, but they have not been set up for success. If they have only ever received minimum safe training packages and reduced experience at sea, we should not expect them to have the same levels of first-hand knowledge as their predecessors.

The fallback in this situation would be to lean more heavily on prescriptive doctrine. Yet this path is closed as well: the Navy lacks both the staff capacity to generate doctrine at the necessary pace and the available platforms to validate it. Borrowing doctrine from allies offers little relief. The capability gap with the US Navy is too wide, while other NATO partners operate under postures too different to be applicable. As for tactics, the problem is the same. Modelling and simulation have their place, but they cannot replicate the lived, iterative process of refining tactics at sea. Without that real-world application, even our most complex and expensive national assets risk falling short of their full operational potential.

For the Submarine Service then, the problems are obvious, the solutions seemingly not so, at least if we continue as before. There has been much discussion across the defence enterprise about the part drones or Uncrewed Underwater Vessels (UUV) might be able to play. Notwithstanding ongoing challenges in development and application, all commentators seem to agree that UUV and drones will supplement crewed submarines, not replace them. The latest Strategic Defence Review re-states the UK’s commitment to Nuclear Deterrence, through a “minimum, credible” number of SSBNs and recommends a replacement SSN be procured to relieve the pressure on the Astute-class. Whilst we can breathe a sigh of relief that we are not about to return to the uncertainty that pervaded before SSN(R) (the forerunner of SSN-AUKUS) was confirmed, it is notable that the SDR does not venture a view on how many SSN are required. In his response to the SDR the Prime Minister announced that the UK would build “up to 12” new SSNs, a number widely accepted as the ‘right answer’ amongst submariners given the current demand geopolitically.

But SSN-AUKUS is currently estimated to cost £2.5bn per platform. What if 12 SSNs transpire not to be an affordable answer, despite being the right one? In response to this conundrum, the RN could consider shadowing the approach taken in the 1980s with the Upholder-class and investing in conventional diesel-hybrid (SSK) powered submarines to complement a core of SSNs. This would not be a simple undertaking, generating industrial complexity in supply chains and sustainment, and the need for updated training and doctrine as a substantial new capability is added to the Royal Navy. Given the challenges associated with trying to re-establish a sovereign capability in conventionally powered submarine production is a challenging endeavour on grounds of cost, time, and available workforce, dependence on a partner may also be necessary to consider. This, in turn, goes against the government’s current approach of emphasising ‘UK first’ in defence spending, which will invariably be challenging. But on this complex and urgent issue, it may be necessary to think outside of the box.

And there are viable options: SAAB’s Blekinge-class is currently costed at approximately £530m per platform and will replace Sweden’s Gotland-class boats; and the Type 212 from Germany’s TKMS, on order for the German and Norwegian navies is £797.5m per platform. Purchasing four SSKs alongside nine SSNs could deliver more platform availability than 12 SSNs, and for a lower upfront outlay to the taxpayer. The cost advantages of this move could be substantial, alongside the availability advantage.

Nine SSNs would enable a fleet where three can be held at Very High Readiness (VHR) to take on the tasks that require speed, range and endurance, including one to service the requirement for a boat to deploy to the Indo-Pacific theatre in support of the AUKUS commitments. A force of four SSKs would then deliver a further two platforms which could be used for tasks that are less dependent on speed and range but strategically important nonetheless. Conventional boats are able to operate in shallower waters than SSNs meaning that operations to protect critical undersea infrastructure in the North and Baltic Seas would be possible – a welcome boost to NATO facing a belligerent Russia.

Operations in the littoral, especially for specialist use cases, would be possible without the need for the sort of design change imposed on the Astute-class. Those changes altered the hydrodynamics of the boat. They were intended to make Astute capable of delivering challenging operations that would involve considerable periods of bespoke training and rehearsal for which in reality they have very seldom been available.

A conventional submarine could stand entry duty on the approaches to home as a ‘de-louser’ for an SSBN on work up, or deploy alongside those returning from deterrent patrol to ensure no unwelcome Russian attention. And it is feasible that the Navy could choose to deploy an SSK where the SSBN isn’t planning to be, to distract attention, or to deploy more than one to generate ambiguity about out or inbound routes. SSKs could also be part of an ASW network, deploying UUVs to extend their range. Of course, an SSN could perform that task too, but that tasking doesn’t make best use of the SSN’s virtues of range and speed.

The use of SSKs would also relieve some of the logistical pressure on the Submarine Command Course, the internationally esteemed ‘Perisher’. The standard length of the course is six months, but a lack of platform availability has seen more than one cohort of students suffer an elongated programme lasting double that. And, aside from prospective COs, Command Teams have less ‘in contact time’, further reducing that library of experience referred to earlier. Whilst time spent in the Command Team trainer ashore is never wasted, it cannot provide the same value as tracking a live target at sea: the levels of fatigue, stress and uncertainty are very different, and the value of the live experience outweighs that of the simulator.

The intensity of operations in an SSK, where each member of the boat’s company has multiple roles and responsibilities at a relatively junior level, will develop critical experience – an area that is regularly cited as a source of concern by stakeholders across the submarine enterprise. The whole crew would benefit from this uplift, and those benefits would be felt across the flotilla, in every class of submarine and in every shore staff, whether it be in Navy Command HQ, the Operational Command in Northwood, the DNO, or the Delivery Agents in Bristol.

A blended fleet could offer significant advantages in through-life costs, but, as noted, it could also challenge the government’s defence prosperity agenda, since the UK’s most viable routes to procurement would likely be to procure boats from abroad. While Britain has the rare advantage of a nuclear submarine industrial base, it is already stretched by demand and lacks the skills, expertise, and capacity to expand into conventional submarine production. Strong options exist among allied suppliers, and purchasing from them would be a pragmatic choice that serves the Royal Navy’s operational needs. Importantly, the RN could still integrate British systems, such as sonar, weapons, or combat systems, ensuring that investment continues to flow into UK industry.

As for the challenge of training teams to crew the boats, the RN could partner with the build or lead nation to develop a seed corn approach in the way that P8 crews developed their experience in the US for years before the RAF took delivery of the aircraft. The RN’s submarine service has excellent and deep relations with all of the potential boat building nations, and there is little doubt that they would welcome the opportunity to strengthen those ties. Using the seed corn approach would allow the RN to train and develop a first of class Ship’s Company and a FOST team to ensure that the team met RN standards, could operate their platform safely, exploit its capabilities to their maximum extent and be ready to train the crew for Boat 2. Thereafter, to borrow a term from the nuclear Navy, the capability would rapidly become self-sustaining.

From a recruitment and retention perspective, SSKs offer clear advantages. Unlike nuclear submarines, they can access a wider range of ports and could even be base-ported in locations such as Gibraltar. They also provide an alternative to the demanding prospect of six-month SSBN patrols, making service more attractive to potential and current submariners. While the challenges of congested bases and limited dock space are real, practical agreements could be made to carry out maintenance either at the original shipyards or at the facilities of the parent nation.

Bringing a new class of submarine into service would be challenging and expensive. Set alongside the other challenges faced by the Service it may appear daunting, even overwhelming. But if we can get around these challenges, such a lateral move to increase submarine availability may be necessary to set the submarine service on an even keel and avoid defeat in the longer-term. Though UUVs may extend detection ranges in time, but they remain years away from meaningful impact and decades from offering the lethality of a crewed platform. To deter Russia and – if necessary – to fight and win, will take more boats in the water, not fewer. To preserve the Royal Navy’s ability to operate a credible nuclear submarine fleet in the decades to come, it may be time to consider what once seemed unthinkable: supplementing it with conventional propulsion.