Global Corvette

Type Designation: ?

Source: VT Shipbuilding

Source: VT Shipbuilding

Specifications

Unknown

Notes:
Project designation:  URD ?
Status: Study only
In Service Date:  ?

The Global Corvette is the title used for a request for information issued by the MOD to industry (BAE Systems, VT Group et al) in mid-2004.

It has been suggested that the study could become a partial replacement for the Future Surface Combatant (FSC) project which was cancelled in in late 2004. 

The DPA's Future Business Group is currently  managing the Global Corvette concept (apparently still under the  FSC banner!) - but it should be emphasised that it is only at a very early, study based, stage in the development cycle.

Timescales

Industry submitted their concept and proposal to the MOD by the end of 2004, and seems to have very little expectation that the study will progress any further.

Further development is dependent on it being proven to be impractical and economic to retain existing Type 23 frigates in service much beyond about 2015, and of course the availability of funding.  There is also a desire to use the Global Corvette project as an agent to help level out the workload at UK naval shipyards. 

In the unlikely event that the Global Corvette study develops in to a project, Initial Gate and entry in to the Assessment Phase seems unlikely prior to 2008, with the first of up to 10 units entering service in the second half of the next decade. 

Platform Design

Very little information has so far emerged about the MOD's thinking in connection with the Global Corvette.  The size, shape and sophistication of the ship selected as the Global Corvette will be determined during the Assessment Phase, however the DPA  has issued a Request for Information (RFI) to industry to help inform the User Requirements Document now being developed.  In response to the RFI, BAE Systems, VT Group, Thales and Rolls-Royce responded in Autumn 2004 with information on a broad range of concepts and designs.   Options range from in diversity from a well equipped Offshore Patrol Vessel (OPV) to an advanced and very capable  "corvette" along the lines of the USN's Littoral Combat Ship programme (LCS).  Displacements range between 1500 and 3000 tonnes.

It is very important to differentiate between the two extremes.  Unsophisticated, and relatively low-technology  warships of up to 2000 tonnes optimised to undertake duties such as anti-drug and anti-piracy patrols in low threat situations can be built for as little as £25-30 million (e.g. the OPV(H)).  But a fast, well armed, high technology, network enabled, small warship built using innovative materials and techniques would cost £120-170 million.  The Assessment Phase will include detailed cost-benefit analysis of the more hulls or improved capability trade-off against various requirements.   

The role of the Global Corvette is still be fully defined, but desired capabilities include an ability to operate forward in shallow, coastal areas where larger ships cannot.

Reduced manning and low running costs are also expected to be important requirements. 

Propulsion

The FSC IPT was considering mandating very high speeds (40-60 knots) for Global Corvette.  Currently no major RN surface warship is able to exceed 30 knots, and historically few have been able to sustain over 35 knots.  Such high speeds will present significant design, engineering, and propulsion challenges.    

In March 2004, BMT DSL was awarded a FSC related study by the Ministry of Defence to assess fast ship enabling technologies.  This broad-ranging study will address both current and future technologies in the naval and commercial ship markets, across a range of platform sizes from combatant up to support ship displacements. Aspects to be investigated will include novel hullforms, dynamic lift systems such as foils and lifting bodies, prime movers, propulsors, and other enabling technologies, assessing the constraints and impact of adopting such technologies; including affordability, credible payloads and speed targets.  This study will support decisions on the characteristics of future platforms, identify the constraints and enabling technologies and inform future investment decisions and concepts of operation development.

Trimaran Hull Design

One design option for the Global Corvette is a revolutionary trimaran hull concept with a slender main hull and two outriggers.  There are numerous theoretical advantages of a trimaran hull form with a slender central hull with outriggers over conventional mono-hulls: 

• Reduced hull resistance at higher speeds resulting in typically 18-20% less installed power for an escort sized vessel required to achieve 28 knots
• Wide range of propulsion options
• Greater fuel economy
• Improved stability and reduced motion.  
• Increased directional stability.
• Top weight growth margins are greater.  There are significant additional stability benefits in the area of growth margins.  This will allow equipment upgrades during the life of the ship to be easily accommodated.  
• Increased deck area (up to 40 per cent) on 1 and 2 decks for a given tonnage, offering more space for hangars, helicopter operation and weapons.  Some of the greatest advantages for the trimaran comes from the improved effectiveness of the whole ship design afforded by this very large deck area.
• Improved sea keeping performance at higher speeds, operational in higher sea states.
• Increased stealth - potential for reductions in radar cross section and infrared signatures.  A reduction in heat signature could be gained be exhausting between the side hulls rather than conventional main structure funnelling.
• The side hulls can be utilised for configuring a multiline towed array sonar. 

The Ministry of Defence has been sponsoring research in to triple hulled ships since the late 1980's.  Importantly, the Research Vessel Triton confirmed many of the previously theoretical advantages.