Mind the Gap: Getting Serious About Submarines
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trategic s insights Mind the gap getting serious about submarines 57 andrew Davies and Mark thomson Overview So where do we go from here? The Collins class fleet reaches the end of its currently The Defence White Paper of 2009 promised planned life between 2022 and 2031. to deliver Force 2030, which had as its Based on Defence’s own planning figures, centrepiece a force of twelve new highly new‑design replacement submarines can’t capable long‑range submarines. That’s be delivered fast enough to even replace the not going to happen. We’re already past Collins as they leave service. If current plans the point at which a force of that size are adhered to, a capability gap is inevitable and capability can be in place even by sometime in the late 2020s, and a period of the mid‑2030s. no submarine capability at all is possible. HMAS Dechaineux (left) and HMAS Waller (right) alongside Fleet Base West, HMAS Stirling, Western Australia. © Defence Department April 2012 2 Mind the gap: getting serious about submarines If the Collins fleet were able to have its life Where are we today?—the future extended by eight years, a capability gap of the Collins class could be avoided, but the feasibility of such an 1 extension remains unclear. Information needs Built at a cost of $8.5 billion in today’s dollars , to be gathered as a matter of urgency to allow Australia’s six Collins class submarines were informed decisions to be made. But, even if delivered between July 1996 and March 2003. successful, a life extension program followed From the start, the Collins class experienced by a new‑design submarine would only deliver a succession of problems. The last boat was a six‑boat fleet in the early 2030s. accepted into service 41 months late, and work to bring the fleet up to the desired standard Similarly, on a credible approval, building continues to this day. The current state of the and delivery schedule, a fleet of nuclear fleet is discussed below in terms of both the submarines would be able to replace the vessels’ capability and the interdependent Collins boats, but with no increase in factors of reliability and maintainability. numbers. And there are many practical problems with such a proposal. Capability The purchase of off‑the‑shelf conventional The true extent of problems with the Collins submarines from an established supplier is class wasn’t disclosed to the public until the the only credible option for reaching a fleet late 1990s, long after the first two submarines of twelve in anything like the White Paper’s had been commissioned and the remainder of timeline. However, such submarines would the fleet was nearing completion. As is usually have less endurance and payload than the the case with a new class of submarine, or any Navy wants. high‑tech platform for that matter, there were One way or another, Force 2030 will have a many engineering problems to be solved—a submarine fleet that is a compromise on the point that should be borne in mind when original vision. contemplating the follow‑on class. The story has been told in detail elsewhere2, but the Introduction biggest problems were that, even with many engineering fixes in place, the Collins class still Back in 2009, the government surprised lacked a working combat system and its diesel many people by announcing plans to engines were highly unreliable. replace Australia’s existing fleet of six Collins class submarines with twelve more Remediation of the defects began in advanced vessels sometime next decade. 1999 with the $275 million Submarine Three years later, very little progress has Augmentation project, which sought priority been made and time is running out for a modifications and an interim combat system seamless transition to another class. Absent capability. Then, in 2002, work began in a substantial life‑of‑type extension of the earnest to fix the problems through the Collins fleet, many options—including that ongoing $525 million Replacement Combat of a locally designed submarine—are looking System and $415 million Reliability and increasingly implausible. Sustainability Improvements projects. This paper explores the difficult choices Because of the capability shortfalls and the government faces and highlights the reliability problems, full operational release consequences of further delays. of the class did not occur until April 2004, almost eight years after the first vessel was Strategic Insights 3 commissioned. In fact, no submarine with a operational restrictions on the fleet because fully capable combat system was available of unresolved equipment performance until May 2008, and the operational release problems and, perhaps more seriously, there of that configuration wasn’t granted until are serious problems with the reliability and December 2009. maintainability of the vessels (see Table 1 for definitions of these and other relevant terms). To date, three submarines have been fitted with the new combat system and new torpedoes (under the $426 million New Reliability and maintainability Heavyweight Torpedo project), and work is The diesel engines on the Collins class suffer almost complete on the fourth. On current from ongoing reliability and availability plans, all vessels in the fleet will have the new problems, exacerbated by a shortage of combat system fitted by 2016, six years later spares. At the heart of the problems is the than originally planned. The combination of decision to fit engines that were originally the new combat system and torpedoes is designed for purposes other than their reportedly working well, so at least some of application in the Collins class. Experience the problems with the Collins class have been has shown that the 18‑cylinder engines are solved. Nonetheless, the solution has come at prone to excessive vibration and uncommonly a cost, as the combat system—derived from a frequent component failures. Problems have system designed for nuclear submarines—has also emerged with the vessel’s electric motors a very high power consumption, limiting the and generators, although progress has been power available for other purposes. reported in fixing those systems through in situ repairs. Today, the fleet’s manufacturer, the government‑owned ASC Pty Ltd, claims With three diesel engines aboard each boat, that the Collins class is ‘widely regarded there’s some redundancy inherent in the as the best conventional submarine in the vessel’s design. However, from an operational world’. Presumably, that assessment refers perspective, the unreliability of the engines to the in‑principle performance of the vessel is especially problematic. While deployed, according to its specifications and weapons conventional submarines spend most of their fit‑out. In reality, there are still unspecified time running quietly on batteries so as to Table 1: Key concepts in submarine logistics Concept Definition Indicative metric Reliability The extent to which the submarine and its constituent Mean time between subsystems can be relied upon to operate as intended. failures of mission‑critical equipment. Maintainability The extent to which the maintenance demands of the Actual versus planned time vessel can be met by available infrastructure, labour, spent in maintenance. engineering knowledge, finance and stocks of spares. Availability The extent to which the vessel is available for use. Vessel‑days per year Availability is constrained by both the reliability and available for deployment maintainability of the fleet as well as by the availability on training or operations. of trained crews. Sustainability The extent to which acceptable levels of availability can Projected future be affordably maintained, given expected changes to availability, given expected the reliability and maintainability of the fleet. Generally resources. speaking, sustainability is adversely affected by the ageing of vessels and the obsolescence of components. 4 Mind the gap: getting serious about submarines evade detection. Between times, they put effective combat system and the modern up a ‘snorkel’ to take in air so that the diesel torpedoes fitted, the combination of poor engines can recharge the batteries before the reliability and operational restrictions (not submarine returns to quiet running. While to mention low submariner numbers and recharging, the submarine is vulnerable to limited crew experience) must limit the detection from the acoustic and thermal practical employment of the boats. So, signature caused by the diesel engines and although the Collins class is at least allowing their exhaust—not to mention the radar and the Royal Australian Navy (RAN) to rebuild visual signature from the snorkel. its submarine workforce, its usefulness as a practical weapon of war is uncertain. The ratio of time spent recharging batteries The picture only gets worse if the vessels’ to that running on batteries is referred to as unexpectedly high maintenance demands a submarine’s ‘indiscretion ratio’, and is a key and consequent poor availability are taken measure of the vessel’s operational capability into account. because it’s directly related to the probability of detection. If one of the three engines on board a Collins boat fails, the indiscretion ratio The maintenance cycle and is increased by 50%; if two fail, the increase availability is 200% (at that point, there being no further The Collins class is currently maintained on redundancy, the mission will almost certainly a roughly decade‑long cycle composed of be aborted). Similarly, failures elsewhere in a two‑year ‘full‑cycle’ docking period and the submarine’s propulsion system—such an eight‑year operating period. Within the as the generators or electric motors—would eight‑year operating period, the vessels probably also necessitate the termination of a undergo a major mid‑cycle docking, two mission in order to return to port for repairs. intermediate dockings, and a variety of dockings associated with certification extension, battery change and assisted ... although the Collins class is at self‑maintenance.