Defence: Exploring flexibility and design families for future warships
The current political and economic climate is placing intense pressure on nations to ensure that defence assets represent value for money.
One way of achieving this is to develop platforms that are flexible but are still effective in the delivery of specific capabilities in any given configuration; this can be achieved through a balanced use of modular and off-board systems. Using this methodology a common class or family of platforms can provide a range of capabilities by tailoring mission fits to specific roles, such as patrol, mine warfare and hydrographic survey.
Andy Kimber, Chief Naval Architect – Surface Ship Design at BMT Defence Services Ltd discusses the issues and opportunities presented by this innovative approach to platform design. He goes on to explain how the use of capability mapping and characterisation methods is helping to better understand the achievability of both the required operational performance and a balanced, affordable design.
Defining a family
So, what makes a family of ship designs? In one sense it may be interpreted as ships of a common type or role. But to the contemporary ship designer, this is an over simplification. Naval ship ‘types’ can be arbitrarily applied while one vessel design can be adapted to perform different roles provided the basis design has the correct characteristics. Hence, the designer may consider a family of designs more akin to a species of animal. In this context, species being a class of individuals having some common characteristics or qualities: A distinct sort or kind.Expand to read the full article
To the naval architect the fundamental common characteristics are those that define the hull form; it may also relate to design architecture (i.e. overall layout or aesthetics) or other features such as structural style. A key factor in whether the designs can form a common family is whether the chosen roles lead to similar characteristics. The initial impression formed is that the roles traditionally associated with minor warships (patrol, mine warfare, maritime security) demand a vessel with the following parameters:
- Platform sizes ranging from 60m to 120m in length
- Simpler and more commercial approaches than warships but still with military features
- The importance of boats and increasingly unmanned vehicles
- Good sea-keeping characteristics, covering offshore to ocean environments
- Moderate Speed Warship, generally of the order of 20 to 25 knots.
Within the ‘Venator’ family of designs BMT has been developing, the focus has been on identifying synergies between the roles performed and the common design themes which result. Each of the designs in the family are focused both on scaleability of performance and also individual focus towards the more specialist characteristics where required (e.g. mine warfare).
The importance of ensuring that the capability need for platforms and equipment is understood and articulated from the outset of a project is key. To better understand the achievability of the required operational performance and a balanced affordable solution, a process to assist with capability mapping and characterisation can been developed, supported by a framework, database and reference models. These tools can facilitate rapid and informed capability trade during the early concept design process and allow a better understanding of how design solutions compare with other concepts, designs and existing platforms. The need for this level of assessment is particularly important when designing in flexibility, especially where the flexibility is being provided by the integration of off-board vehicles and modular systems. The approach maps the impact on whole ship design of possible equipment, via functions, and capabilities, to high level user defined Operational Requirements (Roles, Missions or Tasks).
The smaller Venator 90 platform offers broadly similar capability to the Venator 110 when configured as a patrol ship. This reflects the similar selection of sensors and weapon systems, derived from the same role profiles, although the Venator 90 generally falls slightly short in performance compared to the Venator 110 Patrol Ship and this reflects the smaller platform; less volume and short range and endurance. The exception is Maritime Manoeuvre, where the greater focus towards mine-warfare within the Venator 90 design is illustrated.
Whilst the two designs demonstrate similar capability plots when configured as patrol vessels, the larger Venator 110 has a greater potential due to its size and this is demonstrated by the Patrol Frigate plot. Here, the same design accommodates a more sophisticated payload such that it can deliver a much greater capability in the majority of the roles, demonstrating how a larger platform has inherently greater potential. However, overall, the similarities in delivered capability can be observed within the designs.
What emerges in terms of characteristics within the family of designs is:
- A greater focus on off-board vehicles as key enablers across a range of capabilities and therefore more weather deck space is prioritised towards stowage of boats or unmanned vehicles of one type or another
- A baseline ability to conduct maritime security, including sensors for air and surface search, suitable weapons to provide a visible deterrence, boats and a helicopter surveillance and boarding
- The capacity to introduce additional control, command facilities
- The ability to embark Humanitarian Aid and Disaster Relief (HADR) type support
- Allow additional military capabilities as a graduated response to the environment to be included
In developing a family of designs, the underlying common characteristics have been clearly identified. This has been founded on a capability assessment of the roles which the designs in the family are intended to perform, combined with technical assessment of common design approaches in the hullform, survivability features and flexibility features.
To date, two designs (with one as two configurations) have been developed within the BMT ‘Venator’ family, focused on a littoral and offshore environment vessel and a larger, globally deployable vessel. Development work on the parent hullform is on-going and preliminary parametric analysis has demonstrated the varying levels of performance obtained for the different vessel sizes, whilst the next stage of work will seek to develop hull lines focused on good seaworthiness principles.
By designing for flexibility, individually tailored designs can be offered, choosing the relevant starting point and using the flexibility to meet specific capability demands. To achieve this, the designs must utilise a mix of flexible spaces for alternative off-board vehicles, modular systems (such as weapons) and containerised spaces – only then is it possible to marry a flexible, affordable solution to one that delivers the required capability.
This article was first featured in RINA's Warship Technology magazine. Visit their website to read similar articles.