Critical Royal Navy submarine refit running late

The oldest of the Royal Navy’s ballistic missile submarines, HMS Vanguard is currently in Devonport undergoing major refit and refuelling. There are strong indications the project is in trouble and she will be unable to return to service at the start of 2020 as originally scheduled, with knock-on effects for the 3 remaining boats that maintain the nuclear deterrent.

HMS Vanguard arrived in December 2015 for her second Long Overhaul Period and Refuel (LOP(R)). Her three younger sisters, HMS Victorious, Vigilant and Vengeance have completed their first LOP(R) at Devonport which averaged about 42 months. As we reported last year, Vanguard is unique in having an unplanned second nuclear reactor refuelling as a precautionary measure. The subsequent three boats will have a second LOP but fortunately, it has been discovered they will not require refuelling.

At the time of writing, the project is in its 44th month. Vanguard is the oldest boat and the additional unplanned refuelling may partly explain why this refit will take longer than the preceding boats. Reliable sources told the Financial Times at the end of last year she was still “in pieces” and the MoD had “low confidence” that Vanguard would meet her originally planned return to the fleet in 2020. Effectively putting the project into ‘special measures’, experts from the Submarine Delivery Agency (SDA) were drafted in to support Babcock in 2018.

During her first 35-month LOP(R) which took place between February 2002 and Jan 2005, Vanguard received the new Core H reactor. This new core design, which has subsequently been installed in her sister boats and on the Astute class submarines from the outset, was designed to avoid the need to refuel at all during their lifetime. Vanguard is therefore the first submarine to have the Core H removed and replaced, a task that was not envisaged when it was designed.

Shrouded in scaffolding and hard to recognise as a submarine, HMS Vanguard in number 9 Dock at Devonport during February 2019. The dark grey rectangular building in the centre of the image is the Reactor Access House (RAH) which is moved on rails and positioned over the submarine’s reactor compartment. Spent nuclear fuel rods are raised into the RAH and new fuel lowered in.  Note ex-HMS Torbay being prepared for long-term storage top right. (Photo: Andy Amor)

9 Dock seen from the opposite angle in June 2019. One might speculate that the RAH still in position over the reactor compartment this late in the schedule suggests the refuelling project is not going well.  Note also RFA Fort Victoria and Tidesurge alongside. (Photo: Andy Amor)

The work on Vanguard is the fifth LOP(R) undertaken at Devonport but each refit is a major engineering feat with unique challenges. Submarine repair is never easy due to the cramped spaces and restricted access while the internal systems are more densely packed together than on a surface ship. At the start of the project, Babcock estimated there were over 25,000 individual engineering tasks that would require 2.5 million man-hours. 2.3 Km of cable to be installed, 32,000 litres of paint applied and 26,000 items of ship’s equipment overhauled. 7,000 welds have to be surveyed and repaired, failure of just a single weld when the submarine was at depth could be fatal and inspection must meticulous.

The poor decision by the Cameron government in 2010 to delay starting the Dreadnought programme to replace the Vanguard-class by five years will apply great stress on the boats towards the end of their lives. Vanguard’s current LOP should be her last major refit until she is replaced by HMS Dreadnought sometime in the early 2030s. This project is effectively a life extension that will have to see Vanguard through another 10-12 years of service. Launched in 1992, the boat will be 38 years old by 2030, she was laid down in 1986 so parts of the boat’s structure will, by then, be 44 years old. Ballistic missile submarines (SSBNs) by their nature are highly complex and it is critical they remain mechanically sound and retain their stealth, neither of these attributes is improved with age.


Should Vanguard’s refit run on into late 2020 or 2021, then it will force the other boats to take on extra patrols that were not scheduled in their lifecycle planning. HMS Victorious is the next boat due to have a LOP and her material state cannot be ideal as it is 11 years since she completed her last long overhaul in July 2008. In this situation, the RN can be thankful it has four boats to maintain the Continuous at Sea Deterrent, but the tyranny of keeping at least one boat on patrol is always a balancing act. Of the remaining two boats, one must be preparing to go on patrol and the other boat maybe in a short-medium overall period in Faslane.

As the chart above shows, each part of the Royal Navy’s submarine programme is interdependent. With just a single facility capable of building submarines (Barrow) and a single dockyard able to refit or dismantle submarines (Devonport), flexibility is limited. Delays to any part of the programme have potentially serious knock-on consequences. As we reported last month, delays to the construction of HMS Audacious and the 3 other Astute-class boats at Barrow may impact the delivery of the Dreadnought class boats, forcing Vanguard and her sisters to keep going. Maintaining older submarines is an increasingly difficult and expensive business, adding risks to the boats going to sea and further cost pressures for the MoD. These problems also provide fuel for anti-Trident campaigners who say “look it’s all too difficult and expensive, we should just give up and unilaterally abandon the nuclear deterrent”. Let us hope Babcock and the SDA is able to quickly grip the issues and return Vanguard to operations as soon as possible. It is vital that the CASD chain, UK defence priority one, remains unbroken long into the future.

Main image: Babcock