The Case for the Development of a Multi-mission Ship in the Australian Defence Force

This article presents the case for the development of a multi-mission ship (MMS) in the Australian Defence Force (ADF). The author argues that, by combining the investment of Sea 4000 (the Air Warfare Destroyer (AWD) Project costing between $4 and 6 billion) and Sea 1654 (the Maritime Operational Support Capability project costed at between $600 and 800 million) and blending these with an appropriate design, a viable MMS could be produced. A multimission vessel has many attractions for the ADF. First, such a vessel could provide missile coverage of local airspace. Second, a multi-mission vessel has the ability to carry large quantities of equipment, personnel and supplies. Third, such a ship could serve as an operational base for the F-35 Carrier Version of the Joint Strike Fighter, and it could carry trooplift helicopters, armed reconnaissance helicopters and the new Abrams main battle tank. If the ADF possessed an MMS capability of between two and five vessels, it would have the capacity to field a joint taskforce equipped with a potent suite of weapons systems and appropriate logistics support. Such a taskforce would be resilient and self-contained when deployed on operations.

The Missile Threat: Defending Surface Vessels at Sea

Modern warfare often involves prosecuting military operation over long distances in which naval surface vessels are a key capability. Yet, such vessels are also vulnerable to attack from ballistic and cruise missiles. The large radar-reflecting and hot structures of modern ships on a flat, cool sea make them easily detectable to adversaries employing stand-off strike attack. As a result, any advanced defence force involved in force projection operations must consider how best to defend its surface fleet. Surface vessel survival has been a strategic and operational problem ever since US air crews under Billy Mitchell showed the potential of air power at sea by sinking the German battleship Ostfriedland with 2000 lb (907 kg) bombs during a trial in July 1921. In the 20th century, through World War II to the development of air- and sea-launched anti-ship missiles during the Cold War, the vulnerability of surface ships of all sizes has gradually increased.

In the ADF in the mid-1970s, there was a bitter struggle over the replacement of the aircraft carriers, HMAS Sydney and HMAS Melbourne. One argument that helped to turn the tide against aircraft carrier advocates was a growing belief throughout Australian defence circles that, in the future, carrier vessels would not be able to survive an attack made against them from precision missiles. By 1982, the ADF had dispensed with its carrier capability in favour of a mixed force of frigates, destroyers and submarines. Yet, today, at the beginning of the 21st century, antimissile defence at sea has greatly improved. However, in order to attain a sufficient level of antimissile protection, a surface ship must be large enough to carry a mixture of both defensive and offensive weapons systems and electronic countermeasures that allow it to deal with a missile attack.

Close-in-weapons systems such as the RIM-116 Rolling Airframe Missile (RAM) are capable of repelling massed attacks of anti-ship missiles and other air and surface threats. Australia’s Nulka decoy systems degrade the terminal kill-probability of incoming missiles. Surface-to-air missile weapons, such as the RIM-161 SM-3, are capable of engaging enemy targets at ranges of up to 75 nm. In addition, the SM-6 ERAM offers a semi-autonomous engagement capability at a distance of about 200 nm. Finally, in a ship that is capable of prosecuting air combat operations, the maritime or carrier version (CV) of the F-35 equipped with an air-to-air weapons system can ‘shoot the shooters’ at ranges of up to 600 nm.

Surface-to-air missile systems employ various aerial technologies, and given the steady development of networking links, there is potential for the carrier version of the F-35 to become the long-range sensor and terminal guidance for missiles such as the SM-6. Aerial technology and networking also offer techniques by which it may be possible to overcome the close-radar horizon problem involved in low-altitude attacks launched from ships. If a future Australian MMS capability were of adequate ‘carrier’ length—that is, about 270 m—it would be capable of lifting an arsenal of some seventy-five SM-3 and SM-6 missiles along with a squadron of twenty CV F-35s. The mixture of sea and air assets embodied in the MMS offers the ADF formidable defensive and offensive firepower and a level of maritime security that is impossible to achieve with smaller and less capable ships.

Joint Operations: The Combined Arms Team Concept

The Australian Army’s combined arms team is a useful concept and, if applied across all three services, would enhance the combat power and force projection of the ADF. However, a methodology is clearly required that permits ADF planners to acquire and develop weapons systems that are compatible in a joint operational environment. All weapons systems must be blended into providing an overall capability matrix that consists of survivability, lethality, multi-dimensional manoeuvre, flexibility, range and persistence.

Figure 1 provides a weapons system assessment of an ADF force deployed to a location that is 1000 nm from a main operating base against an enemy that can mount an air threat. Combining the individual combat capabilities of the joint taskforce at that location using the combined arms team concept delivers superior results than if the various weapons systems were to be considered individually.

An MMS capability is an essential player in any joint taskforce based on combined arms. For example, a multipurpose vessel could protect itself in an area of operations through a ‘bubble’ of air, surface and sub-surface defensive weapons systems. Being a large and capacious vessel, it has the capacity to transport land and air forces and to provide fuel and supplies for ongoing operations. An MMS is also capable of making a substantial contribution to the range and persistence of air assets, thus ensuring that deployed ground forces can enjoy air superiority in their area of operations. If armed with weapons such as the Tomahawk cruise missile and/or the SM-4/RGM-165 Land Attack Standard Missile, an MMS could also contribute to both deep-strike attack and to close fire-support. The key to the success of a multi-mission vessel is its self-defence capability, particularly when pitted against ‘leaker’ missiles that might be encountered during a massed cruise-missile anti-shipping attack. An MMS fleet of between two and five vessels could also provide facilities such as a mobile joint taskforce headquarters, a deployable field hospital and logistics support.

Figure 1. Weapon System Assessment for a Deployment 1000 nm from Home Operating Base—Enemy Air Present

Developing a Multi-Mission Ship in the ADF

An argument for merging the AWD with the Maritime Operations Support Capability ships into a single multipurpose ship project needs to be based on the issues of cost, ability to survive and crew numbers.

Cost

A determining factor in the ADF’s acquisition process is the cost of a project. However, the art of life-cycle costing is not well developed in the ADF. For example, the recently released Defence Capability Plan includes acquisition, but not the through-life support, costs. Yet, it is recognised in most defence planning circles that the latter can be much higher than the former. Capability and life-cycle cost equations should always be combined into a single equation that measures the worth of a platform, or weapons system, against the price involved in its long-term maintenance.

Cost is also related to ship design. In recent years, given the intense competitive pressure in private industry for vessels that have lower acquisition and support costs, there have been rapid advances in naval architecture. As a generalisation, commercial ships today are larger, cheaper, and cost less to own and operate. The design of the MMS should incorporate useful considerations from standard commercial ship design. In US defence capability circles, especially in the joint strike fighter project, one of the new development concepts that the US Air Force has adopted is the notion of ‘capability as an independent variable’. This concept reverses the argument that a defined level of capability will be purchased, with cost as the dependent variable. Viewing capability as an independent variable places a premium on planners to try to avoid large cost-’blow-outs’ and to contain costs by means of appropriate original design and assiduous methods of project management. If the ADF seeks to limit, or to fix, available financial investment in platforms and weapons systems, then original design should take into account the requirements for lower acquisition and support costs in order to maximise fleet capability.

The multi-mission vessel design outlined in Figure 2 is based on a catamaran configuration and includes two decks; elevators between the upper air operations deck and the flight deck; crew housing in the hulls; and missile and sensor housing in the walls of the upper deck. In the design presented, space is provided for air warfare weapons systems, including sensors, launchers and missiles. If a ‘marginal cost’ procedure is adopted, then capability can be added incrementally. Adding capability ‘at the margin’ to a single ship is generally much cheaper than concentrating on the production of two distinctive ship-types. Distinctive ship-types often incur large overhead costs that tend to accumulate in such critical areas as design, construction, engine propulsion and in crew amenities.

Survivability

A second consideration in the argument for an MMS concerns the ability of surface vessels to survive air and missile attack. Projects such as Sea 1448 (ANZAC Anti-Ship Missile Defence) illustrate the requirement to provide each of the larger ships of the Royal Australian Navy (RAN) with some form of self-protection. The ramifications of an enemy missile strike sinking an unprotected maritime operations support capability ship with an embarked Army brigade group aboard would be heart-rending and might involve the loss of several hundred lives. It is essential, therefore, that in any deployment, an air warfare destroyer escort a maritime operations support capability ship. Indeed, the air and missile threat at sea effectively ties both vessels together. Yet this twinning begs a larger question: ‘Why not put all the required capabilities in a single ship which may be cheaper to build and operate?’. A single multi-functional vessel may be more efficient since in a low-threat environment, AWDs risk becoming ‘non-performing assets’. In contrast, an MMS can be employed across a spectrum of operations spanning humanitarian assistance through peace operations to anti-missile warfighting.

Figure 2. The multi-mission ship design

Crew Numbers

A third argument that may be advanced in favour of acquiring an MMS capability revolves around the issue of supportability in terms of crew numbers and their sustainment in an era of declining demography. Given Australia’s falling birth rate, in the future, the ADF in general and the RAN in particular are likely to experience a severe decline in its main recruitment pool of those between the ages of eighteen and twenty-four. This recruitment decline is likely to be well advanced by 2015—the date that coincides with the beginning of the life-of-type (length of service) of the proposed MMS fleet. Like equipment, any workforce incurs both price overheads and marginal costs. In this respect, it is worth noting that commercial shipping has long recognised that crew costs impact on efficiency and profitability. As a result, most modern merchant ships are designed to be operated with as few crew members as possible.

A proliferation of ship types within a single fleet has the effect of increasing the inevitable ‘stovepipes’ throughout a navy. In contrast, possessing fewer distinctive ships assists in the management and organisation of relevant skill-sets within the context of diminishing human resources. Thus, a fleet of between two and five MMS has a better chance of being crewed than a diverse fleet consisting of different types of ships. In this respect, the difficulties experienced with crewing the Collins submarines are indicative of the personnel problems that the RAN may find to be routine from 2015 onwards. 

Designing a Multi-Mission Ship

Figure 2 presents an indicative design of an MMS. The configuration shows a ‘Small Waterline Area—Twin Hull’ (SWATH) system—a system that is stable in rough seas and provides good fuel efficiency. The catamaran design offers large internal deck volume and, in keeping with modern oil tanker construction practice, each hull is double skinned in order to improve the vessel’s ability to survive high-tech attack.

Embarked Forces and Propulsion

In general, land forces would be embarked on the lower deck, and air forces on the upper deck of an MMS. Moreover, when in dock, side-loading doors with in-built ramps facilitate rapid embarkation by troops and equipment. A series of movable ramps and the aircraft elevators are included in the indicative design; they facilitate movement between decks. Aircraft elevators must be capable of moving large helicopters such as the Chinook or the troop-lift helicopter to the ‘flat-top’. The crew’s quarters are built into the walls of the lower deck while fuel is carried below the waterline to reduce fire risk. Ballast tanks ensure the trim and draft of the ship in order to ensure that the SWATH sea-keeping benefits of the vessel are maintained.

The MMS bridge is located on the upper deck, looking forward and outward in order to provide a clean ‘flat-top’ surface for air operations. Because marine propulsion has improved markedly over the past couple of decades, two gas turbines in the underwater hulls driving high-capacity alternators are suggested for an MMS. In order to minimise the risk of collision with dangerous objects at sea—such as semisubmerged containers—hydraulic jets are shown at the bow of the vessel alongside conventional propellers at the stern. In an indicative MMS design, ‘rudderless’ steering is achieved through a propulsion system that is facilitated by propellers with adjustable and reversible pitch. In addition, the ship’s exhaust could be ducted to emerge under the lower deck in order to reduce turbulence and infra-red emissions that might be detected by satellites and enemy patrol aircraft.

Landing Craft

The launch of amphibious landing-craft is achieved from the lower deck of the vessel using a ‘wet’ ramp deployed from the stern. This wet ramp permits landing craft to be launched and recovered while the ship is under way. Am MMS is also capable of carrying extendable ramps and pontoon jetties for the delivery of vital equipment across the shore. Because SWATH ships are generally water-ballasted in order to keep the two hulls just below the surface, it might be possible to reduce the MMS’s draft when unloading equipment and so facilitate better ship-to-shore logistics supply.

MMS Self-Protection

A key to the MMS is the issue of selfprotection, which is achieved by means of a ‘layered defence’. RAM launchers would be situated at each corner of the flight deck, thus giving each weapons-station a 240-degree arc of fire. This wide arc would have the effect of exposing any incoming missile, aircraft, or a fast-moving attack craft to at least two and possibly three RAM launchers. Given the projected dimensions of the ship, such a configuration would provide RAM coverage of most of the volume of the battlespace around the ship, including outwards to the distance of the radar horizon.

Another layer of protection for the MMS might be provided by a series of SM-3/SM-6 missile launchers operating as seventy-five vertical tubes firing from the flight deck. Each missile would ideally be available for rapid launch in order to counter any massed attack by enemy missiles. The provision of on-board missile reloading for the launch tubes while the ship is simultaneously under way would also facilitate mission resilience. Finally, the carrier version of the F-35 could be operated either as an offensive or defensive counter-air platform as required. In short, an MMS would have a substantial strike capability from its missile weaponry and organic naval aviation. It is important to note that the vertical launch tubes are large enough to house Tomahawk cruise missiles while the ADF may, in the future, choose to convert its remaining SM missile stock into the SM-4 land attack missile.

Organic Naval Aviation

The projected MMS is designed to be capable of operating the maritime or CV version of the F-35 Joint Strike Fighter. The CV version of the Joint Strike Fighter has a larger wing area than the Conventional Take-Off and Landing (CTOL) version in order to provide the former with additional fuel, a lower landing speed, larger control surfaces and a strengthened undercarriage. Because the CV version of the Joint Strike Fighter is more expensive than the CTOL version, there can be little doubt that any decision by the ADF to employ the former on an MMS would have a financial impact on the Air 6000 project. However, it needs to be understood that the F-35 CV is likely to be superior in terms of its range and multifunctionality in maritime operations from sea, land and air. If the F-35 is eventually deployed on an MMS, the question of the ship’s size immediately arises. Aircraft can generally land on smaller ships using an arrestor system, but take-off distance is always a critical factor that planners must consider. Take-off distance depends on several variables such as the aircraft’s weight and thrust, the speed of the wind over the deck, the level of assistance derived from launching devices—by, for example, a catapult or Rocket-assisted Take-off (RATO)—and whether a ‘ski-jump’ is fitted to the vessel.

The maximum all-up weight (MAUW) of the F-35 is about 50 000 lbs, and its thrust is 35 000 lbs. In conditions of 20 knots of wind over the deck and a 140-knot lift-off speed, a 200 m take-off run would require a catapult thrust of about 30 000 lbs to achieve a MAUW take-off. A 200 m take-off run would place the MMS’s overall length at about 270 m. However, since the gas turbines on the MMS are capable of providing a substantial amount of electrical power, electric ‘rail-gun’ launchers also could be fitted. These devices are used in electric trains and amusement parks, and on a multi-mission vessel they could, in the future, be used to launch aircraft.

The SWATH configuration of an MMS provides sufficient flight-deck width to allow two parallel ‘runways’ to operate on the ship. These runways permit aircraft movement systems such as lifts, catapults and arrestor cables to be used. They also allow more rapid aerial deployment, the fast recovery of aircraft, and simultaneous take-off and landings alongside operations undertaken by dissimilar aircraft types. The MMS design permits aircraft to be fuelled and armed on the air-operations deck and then towed to the aircraft elevator. Finally, since all ships are vulnerable to attack from submarines and mines, the envisaged MMS would carry a complement of Sea-Hawk or similar aircraft. These assets would be used to place submarine sensors in waters around and in front of the ship in order to provide a submersible detection and engagement capability.

Radar

Detection of threat remains critical in the operational viability of any surface vessel. In the proposed MMS, a telescopic Active Electronically Scanned Array (AESA) radar is included. An AESA radar system has the advantage of being able to track an enemy and to direct counter-fire on several incoming missiles or aircraft while simultaneously continuing the search for other potential attacks. Provided a 100 m extension above the waterline can be established, the radar horizon can be situated at between 22 and 41 nm. Such distances are normally sufficient to permit detection of incoming sea-skimmer missiles and to allow time for the ship to prepare its RAM and Nulka closein-defensive systems.

An MMS would be large enough to carry and operate a powered, dirigible-borne radar. The advantage of this type of sensor is that it can operate at considerable height and at a distance from the vessel, thus denying enemy electronic surveillance assets any opportunity to detect and track the MMS. For example, a dirigible operating at 25 000 ft has a radar horizon of about 200 nm and can detect a launch of cruise missiles at long range. The dirigible radar can also be networked, and therefore provide sensor support and terminal guidance to ship-borne missiles, especially the SM-6 weapons system. In terms of selecting sensor systems to support the MMS, surface-wave radar—currently being deployed in the Torres Straits—should be included in any evaluation. The MMS has large, flat-faced sides to minimise radar emissions, and these surfaces might be suitable as the projection plane for radar ducting. If this type of sensor could be placed on the MMS, it would provide the vessel with an over-the-horizon–style capability.

Conclusion

A multi-mission vessel, as described in this article, would have the potential to deploy an array of missile systems alongside the maritime version of the F-35 Joint Strike Fighter, so providing the ADF with a powerful sea-borne capability. If these weapons systems were then combined with remote sensors such as a dirigible-borne fire-control radar, then the MMS would represent a capability that is less vulnerable to attack in comparison with both the Air Warfare Destroyer and the Maritime Operational Support Capability vessels.

There are two critical factors involved in modern naval ship acquisition and development: vulnerability and cost. In examining the possibility that an MMS capability might replace the Air Warfare Destroyer and the Maritime Operational Support Capability ships in the ADF, this article has taken account of both of these factors. In making any formal comparison between the viability of these three vessels in the future, the ADF needs to pay close attention to issues of design and configuration that simultaneously counteract areas of vulnerability and financial cost. At the same time, planners should also undertake detailed life-cycle costs and not rely solely on acquisition cost. Life-cycle costs might be contrasted against current methodologies that are used to determine existing capability proposals. Another measure that the ADF might also consider as part of any formal assessment process might be to hold a well-funded design contest for the best plan of a multi-mission vessel that meets Australian operational needs. Such a contest would exploit current innovations in international ship design and direct these towards the naval sphere. Finally, a design contest may also provide a unique opportunity for state-of-the-art commercial shipping design to be merged with the challenge of producing vessels that meet Australia’s contemporary maritime warfare requirements.