Papers & Publications

A Novel Approach to the Analysis of Sinking Ships: Combining Vulnerability, Stability and Escape & Evacuation Simulations

GODDARD, R. (Steller Systems), SCHOFIELD, J. (Survivability Consulting Limited), MENZIES, D. (Survivability Consulting Limited), MARSHALL, S. (UK MOD), THOMPSON, H. (Steller Systems)  15th International Naval Engineering Conference and Exhibition (INEC), 2020

At present naval ship ultimate stability, Escape & Evacuation (E&E) analysis and operator guidance are largely produced independently. Carpet plots are calculated quasi-statically giving estimations of vessel likelihood of survival using delineations of “poor stability” and “vessel lost” to the command. The definition of poor stability does not account for the dynamic effect of sea states on vessel motion. With advances in the software used to model threats and resultant ship damage effects, a new approach is proposed whereby E&E is modelled as a ship function in a survivability analysis. By integrating and automating this analysis with state-of-the-art E&E and seakeeping software, an ultimate stability carpet plot is produced giving times to sink based on time domain seakeeping simulations. In parallel, escape times are generated including the effects of flooding and ship motions on movement of personnel which are then compared to the calculated sinking times. Through a combined consideration of threat, flooding and ship motions the escape arrangements of a vessel can be improved. It is possible to conduct this combined analysis in a cost and time efficient manner through the use of the tools developed as part of this work.


The Autonomous Machinery Design of Tx Ship

EDGE, W. (Steller Systems), FIELD, C. (Rolls-Royce), WALSH, K. (Thales UK)  15th International Naval Engineering Conference and Exhibition (INEC), 2020

Today’s naval platform procurement processes are dominated by both fiscal and manning pressures that result in lean and ultra-lean-manned technologies being integrated into vessel design. Concurrently there has been huge advances over the last 5 years in ‘systems automation’ and platform autonomy. The vessels that make up tomorrow’s navies will be a force mix of manned, un-manned, or ‘optionally-manned’ platforms.

The Transition Ship (Tx Ship) is a Thales concept for the future development of naval warfare: an optionally manned trimaran that introduces the option of unmanned warships whilst retaining the alternative of keeping the man-in-the-loop during early maturation of its systems. The design showcases the benefits of optionally manned assets and offers commanders a flexible platform for anti-submarine warfare, mine countermeasures or intelligence gathering missions, with its technologies also helping reduce manning on conventional ships through state-of-the-art sensors and effectors.

Critical to realising optionally manned vessel operation is fully autonomous management and control of the ship’s mission systems and machinery systems. A manned Engineering Department traditionally keeps the vital systems on board available enabling Command to fight the ship, these include monitoring the performance of machinery system for extended periods, routine equipment maintenance and battle damage control. On Unmanned Surface Vessels, these functions are still very relevant but now need to be undertaken without humans onboard.

This joint paper by Tx Ship consortium members Thales, Steller Systems and Rolls-Royce, discusses the design practices surrounding power and propulsion system and auxiliary systems design considering the lean manned and unmanned missions. Central to this is the selection and optimisation of these systems with respect to availability, rather than more traditional metrics in order to enable the unmanned mission. These systems are fully integrated with the autonomous machinery controller which operates the marine systems in support of the vessel’s mission and calculates the vessel capabilities and impact of health events to assist with mission planning. The control, maintenance, and battle damage concepts designed for Tx Ship’s Marine Engineering systems address the unique challenges of supporting unmanned vessels and contribute to the vessel’s unique autonomous mission capability; these challenges will be outlined in this paper.


Large Naval UUVs – Navigating Between Simple and Very Complex

BINNS, S. (Steller Systems), HARRIS, K. (Steller Systems), PAYNE, G. (Steller Systems)  15th International Naval Engineering Conference and Exhibition (INEC), 2020

There are a wide range of Unmanned Underwater Vehicles (UUVs) in operation today and they already include a vehicle with 45te displacement. Technology developments in underwater communications, autonomy, and battery and power systems, driven in part by the automotive industry, mean that many previously perceived barriers/blockers can be overcome, and underwater capability opportunities realized.

These opportunities include distancing operators from threats, reducing cost, but also reducing manpower requirements for mundane operations. Many nations require these roles in territorial waters, the extended neighbourhood and expeditionary operations. This and payload requirements conspire to drive future vehicles into a less well understood design bracket between current small UUVs and manned diesel-electric submarines.

This paper describes some of the resultant Large UUV design challenges and opportunities such as shorter development cycles, the risk of an unstable design space between relatively simple expendable UUVs and very complex manned submarines, the need for reliability and applicable rules and standards. It describes a design methodology that applies light-touch system engineering principles to vehicle concept development to address these challenges. This is supported by development and description of an illustrative Large UUV design which provides a good balance of cost, complexity, and capability.


The High-Capacity Expanding Lifeboat HiCEL – Meeting the Modern Search & Rescue Challenge

WRIGHT, J. (Ministry of Defence), PAYNE, G. (Steller Systems)  14th International Naval Engineering Conference and Exhibition (INEC), 2018

The Mediterranean migrant crisis has resulted in the highest population displacement since the Second World War. In 2016 alone, over one million made the journey across the sea. Since 2013 over 15,000 have died as a result of this journey. Small vessels such as wooden fishing boats and RIBs are commonly used by smugglers as transport. These are often unseaworthy and filled with numbers of passengers far exceeding their intended capacity.

When failure occurs, rescues are typically conducted by the nearest available vessel. These vessels are often ill-equipped for a large-scale Search and Rescue (SAR) operation making it highly dangerous for all involved. The size and quantity of lifeboats available are often insufficient for the large numbers of people to be rescued; as a result, repeat journeys are required, making the rescue process slow, inefficient and hazardous.

This paper outlines a novel solution to this problem. A concept design is presented for a rapidly expandable lifeboat capable of holding large numbers of passengers, whilst still fitting into the operational envelope of common davits. The unique inflatable design can be deployed quickly from a range of vessels and aeroplanes offering an immediate platform from which disembarkation onto a suitable vessel can be achieved. CONOPS are outlined along with the required capabilities of the design. Drop stitch technology is identified as a viable means of manufacturing the large inflatable platforms.

Finally, the paper discusses an alternative solution, retrofitting existing enclosed lifeboats with the solution to offer a more cost-effective alternative.

Link to paper (IMarEST members only; alternatively please contact us for a copy of the paper)


Humanitarian Operations:  Not a Grey Area

GODDARD, R., HORNER, D., PEDDER, S., PIPKIN, C.   13th International Naval Engineering Conference and Exhibition (INEC), 2016

Responding to natural or man-made disasters forms a key part of the Royal Navy’s (RN’s) remit, deploying its highly skilled workforce to deliver aid, provide life-saving equipment, restore infrastructure and conduct evacuations and repatriations. Currently humanitarian operations are conducted by a variety of RN vessels, drawing upon the skills and adaptability of their crew. However the vessels, which are designed primarily or exclusively for military operations, are required to operate outside of their design intent and so provide a sub-optimal humanitarian response; furthermore, conducting humanitarian operations prevents the vessels from conducting military duties and interrupts their operational programmes.

With both the overseas aid and Ministry of Defence (MOD) budgets under increasing scrutiny, it is important to ensure that both are being used in the most effective manner; can more be achieved using a different approach? The provision of dedicated Humanitarian Operation Ships (HOS) has the potential to offer a more targeted and efficient response to this core aspect of naval operations, whilst providing a range of other benefits.

This paper draws together arguments for and against the development of one or more dedicated HOS, and discusses the requirements for such a vessel type and potential operating models. The financial implications of this approach are estimated, based on the cost of recent humanitarian operations, to demonstrate that such an approach is financially viable.  Finally, a concept design for a HOS is presented in order to demonstrate how the benefits outlined above can be realised.

Link (members only)


Small Combatant Accidental Damage Extents

GODDARD, R., HORNER, D. , MARSHAL S.  14th International Ship Stability Workshop, 2014

A cost benefit analysis has been conducted to understand how the extent of transverse watertight subdivision as a result of accidental damage extent requirements drives vessel cost, and where the balance lies between cost of increasing survivability and cost of vessel loss. The results of this investigation suggest that a 15% accidental damage extent is appropriate for a small naval combatant.

A great deal of work has been conducted in recent years concerning the derivation of appropriate accidental damage extents for naval vessels; this work has focussed predominantly on extents determined as a percentage of vessel length. Traditionally however, small vessels less than 90 metres in length have struggled to comply with such a standard and have consequentially been certificated against an extent based on number of compartments.

This paper explores the impact on small combatant design of moving from a two compartment damage requirement to a 15% length damage extent through a series of design explorations on four current small combatants. The implication of a 15% extent is examined with regard to the respective changes in ship size and watertight definition required to achieve compliance, and corresponding conclusions are presented.

A cost benefit analysis has been conducted to understand how the extent of transverse watertight subdivision as a result of accidental damage extent requirements drives vessel cost, and where the balance lies between cost of increasing survivability and cost of vessel loss. The results of this investigation suggest that a 15% accidental damage extent is appropriate for a small naval combatant.

A great deal of work has been conducted in recent years concerning the derivation of appropriate accidental damage extents for naval vessels; this work has focussed predominantly on extents determined as a percentage of vessel length. Traditionally however, small vessels less than 90 metres in length have struggled to comply with such a standard and have consequentially been certificated against an extent based on number of compartments.

This paper explores the impact on small combatant design of moving from a two compartment damage requirement to a 15% length damage extent through a series of design explorations on four current small combatants. The implication of a 15% extent is examined with regard to the respective changes in ship size and watertight definition required to achieve compliance, and corresponding conclusions are presented.

Link (members only)


A New Approach to the Derivation of V-Line Criteria for a Range of Naval Vessels

GODDARD, R. DAWSON, N., PETERS, A.  14th International Ship Stability Workshop, 2014

Previous work has gone some way to understanding the applicability of the current naval V-lines standards to modern day naval designs by carrying out damaged vessel simulations using the CRN developed time-domain ship motion program FREDYN. The work presented in this paper seeks to further this understanding of V-lines by analysing the damaged motions of six vessel types, varying from a small Mine Counter Measure Vessel (MCMV) to a large auxiliary, and implementing a new methodology for the calculation of probabilistically derived dynamic motion allowances for heave and roll. Furthermore, analysis has been conducted in sea states up to a sea state 6 in order to understand the applicability of V-line criteria at greater wave heights and periods. This paper compares heave and roll allowances derived from the probability of exceeding water heights on the bulkheads bounding the damage in varying sea states for each vessel type, each with two damage cases at eight wave headings and at two speeds. Conclusions are drawn regarding the suitability of current criteria for vessels of varying size and design and their sensitivity to sea state.

Link


UXV-Enabled Totally Modular Combatant

GODDARD, R., SKARDA, R.  12th International Naval Engineering Conference and Exhibition, 2014

The growing capability of unmanned vehicles requires the hosting combatant to be designed in a different way.   To keep up with the pace of Unmanned Vehicle UXV design and fielding requirements, the ship must be adaptable, modular and a flexible balance must be achieved between on-board and off-board capability in order to maintain an acceptable overall system cost. Operational Doctrine and Concepts must be entwined with the overall system design, where the system includes; people, platform, combat systems, network and unmanned systems. A totally modular approach to design, construction, fitting out, systems deployment and re-configuration enables the platform and the role to be independent. Integrated propulsion systems to enable future energy weapons to be deployed must be balanced with procurement costs and through life costs as well as maintaining simplicity in the platform yet allowing freedom of manoeuvre through good speed and long range.  Combined Engagement Capability, Open Combat Systems Architecture and the ability to cross-deck unmanned systems should allow a more cost effective and smaller vessel to provide the capability edge, where additional survivability comes from the task group network of supporting combatants and fleet of unmanned vehicles. The Steller Systems ‘Hermes’ concept shows one way that this balance can be achieved and the advantages to the operator and coalitions through making capability, platform agnostic.  The form factor of a small frigate provides the required balance between size and capability, cost and performance.  Through modular design, arrangements to support a multitude of unmanned vehicles and an efficient hybrid electric propulsion architecture, will show how the future of combatant design will be a trade between organic integrated systems, unmanned systems, open combat systems architecture, platform arrangement, platform numbers, personnel training and propulsion systems architecture.

Please contact us for a copy of the paper.


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