Astute: seventeen month delay may impede Dreadnought programme

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HMS Audacious in the Devonshire Dock Hall with HMS Anson (left) and HMS Agamemnon (right) under constrcution. Image credit: BAE Systems

In mid-October the government announced that production of the fourth Astute-class submarine was nearly 17 months behind schedule, a delay that is likely to impact on the timetable for building the Dreadnought-class submarines. HMS Audacious was due to be handed over to the Navy in August 2019, but due to a fault handover is now expected to be January 2021.

The Astute-class submarines are nuclear powered but armed with conventional weapons. They are being built by BAE Systems at Barrow-in-Furness. The Astute submarines are intended to replace the Trafalgar-class submarines, but due to delays in the Astute programme, some of the Trafalgar submarines have had their service lives extended to more than 30 years. HMS Audacious is the fourth Astute-class submarine to be built, following HMS Astute, HMS Anson and HMS Artful, which are currently in service.

Parliamentary scrutiny

The delay was announced in a letter from Stephen Lovegrove, Permanent Secretary of the Ministry of Defence (MoD) to Meg Hillier, Chair of the Public Accounts Committee. Since April 2017, it has been government policy to keep Parliament informed of their assessments of the progress of its largest projects.

When questioned on the subject by the Defence Select Committee the Secretary of State for Defence, Ben Wallace, said that the fault which caused the delay was unique to HMS Audacious and had not occurred in the first three Astute submarines. Mark Francois MP, a member of the committee, called the Astute programme a “disaster”, and said that “[s]omething went horribly wrong at Barrow and has continued to go horribly wrong for years.”

In evidence to the committee, Ben Wallace said that the fault with HMS Audacious would be addressed by replacing the relevant part with one that had been intended for one of the later Astute submarines. The MoD has refused to give full details of the issue, citing security concerns.

What we know about the fault

Astute submarines are built as separate modules and horizontal hull sections. The modules contain the main pieces of machinery, and are slid into the hull sections on rails. The hull sections and modules are built in various workshops across the Barrow site, but assembly of the submarine takes place in the Devonshire Dock Hall at Barrow, the second largest indoor shipbuilding facility in Europe. Publicity photographs show that three submarines can be worked on in the Devonshire Dock Hall in parallel, but there does not appear to be space for a fourth to be assembled at the same time.

During assembly the hull sections are welded together, and once the final welds are completed the hull is closed, meaning that the interior of the submarine is only accessible through hatches. After final outfitting the submarine is launched, by being lowered into the dock at Barrow until it is floating. HMS Audacious was launched in April 2017. Various submarine systems are then tested in the dock basin before fuel is loaded into the reactor and the submarine begins running under its own power.

The timings of some of the milestones suggest that problems may have been apparent for some time, and the MoD has waited until the original in-service date had passed before making them known. One of the most significant events of the basin trials is the first time the submarine is fully submerged in the water. This first dive of HMS Audacious did not take place until January 2018. The 10 month gap between launch and first dive is twice as long as the five months between launch and dive for HMS Astute, the first submarine of the class.

However, it seems that until recently the August 2019 date was expected to be met. According to campaign group ‘Save the Royal Navy’, preparations were being made in late 2018 for the HMS Audacious to leave Barrow early this year, but the group reported that the submarine was still in the dock in Barrow in July.

It seems probable that during the delay HMS Audacious has been returned to the Devonshire Dock Hall for the faulty part to be replaced. HMS Astute is known to have been returned to the Hall for remedial work, and it appears that work assembling HMS Agincourt, the final Astute-class submarine, has been delayed in order to leave space for the repairs to HMS Audacious. All previous Astute-class submarines have had a ‘keel laying’ ceremony when the first hull section was moved into the Hall. No public announcement has been made of a keel laying ceremony for HMS Agincourt, despite the Barrow local press announcing the delivery of the ‘final’ hull section to the Devonshire Dock Hall in August.

There are some differences between HMS Audacious and the first three Astute-class submarines, including upgraded electronic systems, so the fault may have occurred in one of the new systems or components. If the fault was not discovered until after the hull was sealed, efforts to repair the fault may have been complicated by access issues.

What will happen next

It is not clear whether HMS Audacious has yet proceeded to the stage of loading fuel into its nuclear reactor. This would normally follow basin trials and powering up the reactor would be one of the final steps before beginning its contractor sea trials. After successful completion of these sea trials there will be a public commissioning ceremony. This is a ceremonial milestone, but usually happens close to the time the the submarine is formally handed over from BAE Systems to the Navy.

Commissioning is likely to be followed by further testing and training before the submarine goes on operational deployment. There were nearly three years between HMS Astute’s commissioning and first operational deployment, although the time period was shorter for HMS Ambush, the second Astute-class submarine. The MoD does not appear to have announced operational deployment of HMS Artful, the third of the Astute submarines, which was commissioned in 2016. In 2017, just over a year after commissioning, it was reportedly undergoing repairs.

The immediate consequence of the current delay will be that the Trafalgar-class submarine which HMS Audacious was due to replace, HMS Trenchant, is likely to have its service life extended further than originally planned. In 2017 HMS Trenchant was re-launched after a “complex and lengthy” maintenance period which required 650,000 labour hours in order to extend its life to 2019. In evidence to the Defence Select Committee, MoD representatives conceded that the further extension would involve a greater maintenance cost.

Potential knock-on delays

As well as the apparent delay to the construction of HMS Agincourt, the last Astute-class submarine, there are likely to be knock-on delays to the construction of the Dreadnought-class submarines. The first of these, HMS Dreadnought will be assembled in the Devonshire Dock Hall, presumably once the fifth Astute-class submarine, HMS Anson, has been completed.

The Dreadnought-class submarine most likely to be affected by the delays to HMS Audacious is the third of the class, which will be called HMS Warspite, as it presumably can only begin to be assembled once HMS Agincourt has left Barrow. However, if workers and other resources have been redirected from work on the other Astute-class submarines in order to minimise the delays to HMS Audacious, there could be knock-on delays to all the submarines currently under construction and also to the entire Dreadnought class. Hull sections for HMS Dreadnought are under construction, and the second construction phase of the programme, when work on the second Dreadnought submarine, HMS Valiant, will commence, began in April 2018.

The government no longer publishes in-service dates for the Dreadnought submarines, but it has been suggested that the MoD may struggle to keep a nuclear-armed submarine at sea as the Vanguard-class submarines approach the end of their service life, particularly if there are delays in building their successors. In evidence to the Defence Select Committee, Ben Wallace said that he did not know what the knock-on effects of the delay to HMS Audacious were likely to be, but he described submarine construction capacity as ‘hollowed out’ and said that politicians, the military and industry had all suffered from ‘optimism bias’.