Class Submarine Research Articles

A Computational Study to Predict the Seakeeping Performance of a Surfaced Submarine in Irregular Waves

Abstract In general, submarines are designed to optimize operation below the water surface because they spend most of their time underwater. On the other hand, the performance in the free surface condition is also important because submarines face a variety of scenarios to complete operational missions, and the free surface condition is unavoidable for port departure and arrival. In the case of a submarine, the numerical accuracy of the potential theory for seakeeping analysis is excellent in submerged conditions, but it is poor in free surface conditions because of nonlinear effects near the free surface area. In this study, star-ccm+ was used as a Reynolds-averaged Navier–Stokes (RANS) solver to estimate the seakeeping performance of a Canadian Victoria Class submarine in irregular waves. The results were compared with those of model tests from a published paper. In addition, the potential theory code was also used to assess the seakeeping performance and compare it with computational fluid dynamics (CFD) results. From the calculation results, the motion responses in irregular waves using CFD showed similar trends to the experimental results. In contrast, motion responses from potential code showed significantly larger values than the experimental results. In conclusion, CFD simulations with irregular waves can be a good solution to predict the seakeeping performance of submarines in free surface conditions.

On the Brink: The Climate and Nature Crisis and Risks of Nuclear War

The Russian military invasion of Ukraine on February 24, 2022, and Hamas’ terror attack on Israel on October 7, 2023, signaled the beginning of two of the most recent wars to make international headlines. To date, over 110 armed conflicts are taking place: over 45 in the Middle East and North Africa (Cyprus, Egypt, Iraq, Israel, Libya, Morocco, Palestine, Syria, Turkey, Yemen, Western Sahara); over 35 in Africa (Burkina Faso, Cameroon, the Central African Republic, the Democratic Republic of the Congo, Ethiopia, Mali, Mozambique, Nigeria, Senegal, Somalia, South Sudan, Sudan); 21 in Asia (Afghanistan, India, Myanmar, Pakistan, the Philippines); seven in Europe (Russia, Ukraine, Moldova, Georgia, Armenia, Azerbaijan); and six in Latin America (three each in Mexico and Colombia); with two more international armed conflicts (between India and Pakistan, and between India and China) in Asia.1 This list does not even include such problematic situations as those involving China and the South East Asia region.
 As though these situations of armed violence were not enough, mankind has already passed or is on the verge of passing several climate tipping points – a recent review lists nine Global core tipping elements (and their tipping points) - the Greenland Ice Sheet (collapse); West Antarctic Ice Sheet (collapse); Labrador-Irminger Seas / SPG Convection (collapse); East Antarctic Subglacial Basins (collapse); Amazon Rainforest (dieback); Boreal Permafrost (collapse); Atlantic M.O. Circulation (collapse); Arctic Winter Sea Ice (collapse); and East Antarctic Ice Sheet (collapse); and seven Regional impact tipping elements (and their tipping points) – Low-latitude Coral Reefs (die-off); Boreal Permafrost (abrupt thaw); Barents Sea Ice (abrupt loss); Mountain Glaciers (loss); Sahel and W. African Monsoon (greening); Boreal Forest (southern dieback); and Boreal Forest (northern expansion).2 Closer to home, how can we forget the disaster and devastation wrought by Super Typhoon Haiyan (Yolanda) 10 years ago to date?
 Whether international or non-international, armed conflicts raise the risk of nuclear war. Russia has already “rehearsed its ability to deliver a ‘massive’ nuclear strike,” conducting “practical launches of ballistic and cruise missiles,” and stationed a first batch of tactical nuclear weapons in Belarus,3 and the possibility of nuclear escalation in Ukraine cannot be overestimated.4 Meanwhile, in a rare public announcement, the U.S. Central Command revealed that an Ohio- class submarine (560 feet long, 18,750 tons submerged and carrying as many as 154 Tomahawk cruise missiles) had arrived in the Middle East on November 5, 2023.5 Indeed, “the danger is great and growing,” as “any use of nuclear weapons would be catastrophic for humanity.”6

Computational Investigation of Seakeeping Performance of a Surfaced Submarine in Regular Waves

<i>A submarine is optimized to operate below the water surface because it spends most of its time in a submerged condition. However, the performance in free surface conditions is also important because it is unavoidable for port departure and arrival. Generally, potential flow theory is used for seakeeping analysis of a surface ship and is known for excellent numerical accuracy. In the case of a submarine, the accuracy of potential theory is high underwater but is low in free surface conditions because of the nonlinearity near the free surface area. In this study, the seakeeping performance of a Canadian Victoria Class submarine in regular waves was investigated to improve the numerical accuracy in free surface conditions by using computational fluid dynamics (CFD). The results were compared to those of model tests. In addition, the potential theory software Hydrostar developed by Bureau Veritas was also used for seakeeping performance to compare with CFD results. From the calculation results, it was found that the seakeeping analysis by using CFD gives good results compared with those of potential theory. In conclusion, seakeeping analysis based on CFD can be a good solution for estimating the seakeeping performance of submarines in free surface conditions.</i>

OOO급 잠수함 함교 통신 시스템 오작동 개선 연구

본 논문에서는 ○○○급 잠수함에서 사용하는 함교 통신 시스템에서 발생한 오작동을 분석하고 개선하였다. ○○○급 잠수함의 함교 통신 시스템은 작전 중 사용되는 주요 통신 시스템 중 하나로, 함 지휘 통제를 위해 함내 통신 시스템과 교신 설정을 최대한 신속히 수행하여야 한다. 그러나 자체 시험이나 해상시운전을 비롯한 품질보증 활동 중 함교통신 시스템이 오작동하는 경우가 지속적으로 발생하였다. 특히, 잠항 항해 및 부상 직후에 함교 통신 시스템이 빈번하게 오작동하여 임무를 수행하는데 지장을 초래하는 경우가 많았다. 따라서 본 논문에서는 함교 통신 시스템의 물리적 구조를 분석하고, 이러한 오작동을 일으킬 수 있는 원인들을 분석하여 가장 가능성이 높은 원인을 추정하였다. 그리고 이를 바탕으로 midas NFX을 이용한 시뮬레이션을 통해 장비의 구조적 개선 방안을 도출하였다. 또한, 도출한 개선 방안을 설계 변경을 통해 장비에 적용하여 시제품을 제작하였으며, 시제품에 대해 실상황과 유사한 환경 시험을 수행하여 개선된 장비 성능을 평가함으로써 함교 통신 시스템의 신뢰성을 확보하였다.

Implementation of South Korea's Chanbogo Submarine Purchase Policy

A strong national defense system does not require consideration of empathy, including the geographical factors of the country being examined, the national resources of a country, an analysis of possible threats that will arise, and the development of information technology. Defense is something that is fundamental to the survival of a country. Cooperation between Indonesia and South Korea in the defense industry is centered on the development of the changbogo class submarine and the development of the KFX / IFX fighter aircraft. Seen from the Government's policy, it can be seen that the domestic industry is unprepared to support the independence of the defense industry. This unpreparedness can be caused by the absence of supporting infrastructure or financial support for mass production of defense and security equipment. This scientific work is expected to provide recommendations in defense policy regarding submarine development. This study uses a scientific approach with qualitative descriptive methods and uses implementation tehory by George C. Edward. The results of this study a policy review of South Korea’s Submarine purchase policy . The conclusion of this study are constraints and challenges faced in improving submarines, particularly related to the ability of PT. PAL Indonesia is still limited in the manufacture of the DSME 209/1400 submarine.

Co-Site Interference Study and Mitigation Onboard a Submarine Between Communication and Positioning Systems at L Band

This letter focuses on modeling and studying the RF interference between a civilian Inmarsat FB emitter at 1627 MHz (culprit) and a GPS L1 band maritime system at 1575 MHz (victim) on close antennas proximity onboard a submarine. Once predicted the RFI, we propose the design of an adequate mitigation for it. The chosen platform to host this study is a 3D model of the U.S. Navy retired Los Angeles SSN-688 original class submarine. The proposed methodology consists on calculating through numerical 3D electromagnetic simulation the electromagnetic decoupling between culprit and victim’s antennas on different antenna placement scenarios onboard the SSN-688’s masts; modeling a typical GPS front-end receiver simultaneously excited with both the interferer signal after decoupling, and the GPS weak signal reception; to observe the RFI effects on the modeled receiver circuit; and to finally propose and design an adequate filter to control and mitigate the interference. The result is a pre-filter, to be connected to the GPS receiver front-end before the GPS’s low noise amplifier, which attenuates the Inmarsat signal on the rejection band below the RFI threshold level and inserts a low insertion loss on GPS pass band.

Gaseous pollutants in Indian EKM and SSK class submarines

Introduction: Once a submarine dives, the captive atmosphere inside keeps changing due to release of various pollutant gases. The gases are produced by machinery, cooking, human, paints, batteries, cooking etc. The study was envisaged to measure these gaseous pollutants on surface and in prolonged dive onboard EKM and SSK class submarines. Methods and Material: Detector tubes and pumps were used to measure the concentration of twenty gaseous pollutants in harbour on surface & during sailing in dived condition. In harbour, readings were taken early morning and before secure in the evening. During sailing readings were taken on surface, just after diving and thereafter every four hrs. The readings were recorded in excel sheet and correlated with activities on board at time of taking reading. Results: Only Ammonia and Hydrogen Sulphide were detected at the beginning of the day in harbour, however by the end of the day all other gases were detected except Mercury, Oil mist, Nitrogen Dioxide, Ozone & Arsine. At Sea none of the gases were detected at the beginning of sailing. At 12h post dive all gases were detected except Mercury, Oil mist, Nitrogen Dioxide, Ozone, Halogenated Hydrocarbons & Arsine. Recommendations and Conclusion: The gas concentration values obtained by using detector tubes and pumps were found to be within recommended Permitted Exposure Levels (PEL) for human for continuous exposure. No gas was found to be above the recommended PEL. There was no significant difference in the gas concentration levels in the EKM & SSK Class submarines. Pump and detector tube is a convenient, reasonably accurate and efficient method to measure gaseous pollutants on board Submarines.

Analysis of Submarine with the Study of Mechanical Investigations using Borei - Class Submarine Model

Analysis of Submarine with the Study of Mechanical Investigations using Borei - Class Submarine Model

INDONESIA AND SOUTH KOREA DEFENSE DIPLOMACY: CASE STUDY OF PROCUREMENT OF CHANG BOGO CLASS VESSELS IN 2010-2018

<p>Indonesia has chosen South Korea as a cooperation partner because South Korea is agreed to Indonesia's procurement policy. The research objective was to analyze the stages of procurement of Chang Bogo class submarines and the role of defense diplomacy during the process. This study uses qualitative methodology with its analysis techniques. The study concluded that the procurement of submarines succeeded in terms of the number of submarines, but the percentage of transfer technology provided had not yet reached the minimum percentage of Indonesia’s need and Indonesia must build adequate infrastructure to achieve the independence goals of the defense industry but Indonesia was still experiencing fluctuate economic condition. Therefore, the procurement of defense and security equipment tools <em>(alpalhankam)</em> must adjust to that condition.</p>

Data-Driven Design Solution of a Mismatch Problem between the Specifications of the Multi-Function Console in a Jangbogo Class Submarine and the Anthropometric Dimensions of South Koreans Users

The naval multi-function console provides various types of information to the operator. It is equipment that is key for submarine navigation, and fatal human errors can occur due to the mismatch between the console specifications and the operator’s body size. This study proposes a method for deriving console specifications suitable for the body size of Korean users. The seat height, seat width, seat depth, upper edge of backrest, and worktable height were selected as the target design variables. Using six anthropometric dimensions, a mismatch equation for each target design variable was developed. Anthropometric measures of 2027 Korean males were obtained, and the optimal specifications of the console were derived via an algorithmic approach. As a result, the match rate, considering all the target design variables, was improved from 2.57% to 76.96%. In previous studies and standards, the optimal console specifications were suggested based on the anthropometric data of a specific percentile of users, and it was impossible to quantitatively confirm the suitability of the console design for the target users. However, the method used in this study calculated the match rate using the mismatch equation devised for comfortable use of the console and a large amount of anthropometric data that represented the user population, and therefore the improvement effect of the recommended specification can be directly identified when compared to the current specifications. Moreover, the methodology and results of this study could be used for deciding the specifications of multi-function consoles in several fields, including nuclear power plants or disaster situation rooms.

Australia’s future submarine: shaping early adaptive designs through test and evaluation

The Australian Government selected France’s Direction des Constructions Navales Services to design Australia’s future submarine, the Shortfin Barracuda. This paper evaluates different system developmental approaches that can be applied, such as the U.S. acquisition life cycle and a research, engineer, design, adapt, reflect (RADER) model. The evaluation showed a need for deliberate regard for the significant philosophical, political, military, cultural and economic differences of the French practices compared to U.S., U.K. and Australian. The paper reviews major lessons learned in Australian acquisitions regarding early preview test and evaluation (T&E), including the Collins Class Submarine, and proposes 11 T&E goals, especially early commitment to an estimated seven test sites needed to ensure the early design is proven and low risk. To save substantial overall time and rework, greater investment is needed in the social spaces for critical thinking and T&E to guide the submarine towards a continuously evolving design and build.

The Valve Gear Systems Timing Parameters Identification for Marine Diesel Engines Diagnostics / Identyfikacja Parametrów Układów Rozrządu Silników Okrętowych Dla Potrzeb Diagnostyki

Abstract In the paper results of studies that aim was to develop a diagnostic method for high-speed marine diesel engines are presented. Polish Navy is operating significant number of engines of this type also on board of submarines. Engines of this type do not have indicator valves, which complicates the assessment of combustion process and their technical condition. Polish Naval Academy in Gdynia for years has been developing methods of diagnosing marine internal combustion engines. In recent years, a diagnostic method for high-speed marine diesel engines based on the analysis of envelope of vibration accelerations generated by the valve gear mechanism and fuel system has been developed. Some tests results made on Mercedes-Maybach MB820 engines used on Kobben class submarines are presented in the paper.

How a submarine returns to periscope depth: Analysing complex socio-technical systems using Cognitive Work Analysis

This paper presents the application of Cognitive Work Analysis to the description of the functions, situations, activities, decisions, strategies, and competencies of a Trafalgar class submarine when performing the function of returning to periscope depth. All five phases of Cognitive Work Analysis are presented, namely: Work Domain Analysis, Control Task Analysis, Strategies Analysis, Social Organisation and Cooperation Analysis, and Worker Competencies Analysis. Complex socio-technical systems are difficult to analyse but Cognitive Work Analysis offers an integrated way of analysing complex systems with the core of functional means-ends analysis underlying all of the other representations. The joined-up analysis offers a coherent framework for understanding how socio-technical systems work. Data were collected through observation and interviews at different sites across the UK. The resultant representations present a statement of how the work domain and current activities are configured in this complex socio-technical system. This is intended to provide a baseline, from which all future conceptions of the domain may be compared. The strength of the analysis is in the multiple representations from which the constraints acting on the work may be analysed. Future research needs to challenge the assumptions behind these constraints in order to develop new ways of working.

Maximizing Platform Value: Increasing VIRGINIA Class Deployments

AbstractThe FY11 Report to Congress on Annual Long‐Range Plan for Construction of Naval Vessels (commonly known as the 30‐Year Shipbuilding Plan) forecasts that the Navy's Attack Submarine (SSN) force structure will fall below the requirement of 48 SSNs in 2024, and will remain below the requirement throughout at least 2040 (the limit of the current report). Operating the fleet with fewer ships than necessary to meet commitments around the globe makes it imperative to maximize the mission time provided by each platform. Accordingly, the VIRGINIA Class Submarine Program Office (PMS 450) has developed a plan to mitigate this shortfall in force structure by designing reductions in depot‐level maintenance, thereby improving operational availability and maximizing mission time. This plan is encompassed in the Program Office's Reduction of Total Ownership Cost (RTOC) goals. However, actions arising from pressure to reduce Total Ownership Cost (TOC) may have the potential to inadvertently limit available platform mission time if the full consequences, including indirect impacts, are not rigorously assessed and analyzed in advance. The VIRGINIA Class Submarine Program faced this challenge explicitly in implementing the RTOC program while simultaneously working through details of a class maintenance plan modification for later submarines that adds a deployment to the operating cycle. Reducing TOC, while making changes to both the maintenance plan and the platform design, requires an integrated analytic capability to assess the impact of potential changes to both cost and delivered mission time. Evaluating the impact of maintenance changes on mission time is complicated by interactions between multiple stakeholders involved in controlling and managing the lifecycle of the submarine—including those responsible for maintenance planning (and the ability of the maintenance facilities to execute the work), operations and training, and modernizations. An approach and analytic framework, which captures “TOC Effectiveness” (defined as Mission Time Delivered divided by Net Cost) is needed to balance divergent program and stakeholder goals. To capture TOC effectiveness, a time‐phased dynamic simulation of the lifecycle employment of VIRGINIA Class Submarines (including depot maintenance time) has been developed to determine the likely submarine employment consequences of the plans, policies, and constraints of the stakeholders involved, and to ensure that the lifecycle maintenance plan targets are achieved. The simulation was validated against historical performance of LOS ANGELES Class maintenance execution at public shipyards, explicitly adjusting for known differences in VIRGINIA Class work packages (the first VIRGINIA Class depot maintenance availability did not start until October 2010). Simulation analysis has identified likely results of alternative plans and/or policies and provided insight into where changes can be made across multiple stakeholders to efficiently and effectively achieve program goals for deployments. The simulation is integrated into the VIRGINIA Class RTOC program process to identify specific areas where changes have high leverage to increase mission time, evaluate specific changes proposed by the RTOC effort, and track progress toward achieving mission time goals.

Determination of X-Ray Elastic Constants for Q1N Submarine Pressure Hull Steel

The Canadian Navy has a requirement to conduct on-site accurate residual stress investigations to improve the efficacy of risk assessment and damage tolerance analysis of critical structures. This paper describes the techniques for qualification of the portable miniature X-ray diffractometer (mXRD) for residual stress analysis on Canadian VICTORIA Class submarine (VCS) pressure hulls. The effect that thermomechanical processing has on the X-ray elastic constant (XREC) and resultant stress analysis is discussed. The approach for calibration of the mXRD equipment and calculation of residual stress values from strain measurements is explained. A new methodology for determination of the XREC, based on the ‘multiple angle method’, is presented discussed and applied to describe the stress-strain relation for tempered Q1N steel. This method, which expands on the ASTM standard, examines the change in lattice strain at multiple y angles (∂dfy /∂sin2y) and provides improved statistical error over the ASTM standard. An XREC of 195 ±6 GPa was experimentally determined for Q1N steel using the {211} crystallographic planes of bcc Fe (using Cr Kα radiation) using the multiple angle method.

Analysis of 3000 T class submarines equipped with polymer electrolyte fuel cells

The naval submarines have conventionally been equipped with diesel-electric propulsion. The diesel generators charge the batteries when the submarine is at the surface or at snorkelling depth. This is the biggest short-coming of this system as the submarine can be detected due to the infrared signatures from the exhaust of engines. Present study aims in analysing the feasibility of using fuel cells as a replacement of conventional diesel based system. Fuel cell system is analysed to meet the propulsion load and hotel load. In this purpose, metal hydride and sodium borohydride are considered for fuel and compressed oxygen and liquid oxygen are considered as oxidant. The most effective combination with respect to weight, volume has been analysed. The submerged endurance and distance for various hotel loads under submerged conditions have also been estimated. It is found that the metal hydride and liquid oxygen combination can be easily retrofitted by replacing the conventional system. However, MH/O 2, SBH/O 2 and SBH/LO X require some extra room to be created. All the systems show substantial enhancement in the submerged endurance.

Stress analysis on Canadian naval platforms using a portable miniature X-ray diffractometer

Strain field distribution in a naval platform under dry-dock conditions is complex and represents the cumulative response from residual stress (“locked in” during fabrication of materials and formation of the structure) and static loading stress (e.g., dry-dock loading). The magnitude and distribution of stress fields are a significant concern for the Canadian Navy, where the superposition of applied stresses on residual stresses may adversely affect the performance, safe operational envelope, and service life of naval platforms. Stress analysis was conducted on Canada’s VICTORIA Class submarines using a portable miniature X-ray diffractometer (mXRD) under dry-dock conditions. This paper introduces the concept of “residential stress” as it applies to submarine platforms and discusses the methodology for performing stress analysis with a portable mXRD. The evolution of residential stress during routine pressure hull repairs to Canada’s VICTORIA Class submarines is discussed. In particular, the recent replacement of the diesel exhaust hull and back-up valves on one of the submarines, as well as a pressure hull plate extraction-insertion-weld procedure on another, is discussed.

Surfacing Rescue Container Concept Design for Trident Submarines: Rethinking Submarine Search and Rescue

In the wake of the KURSK tragedy, world navies have focused their full attention to the submarine rescue problem. While many rescue systems exist, none have been able to sufficiently address the gamut of scenarios that place submariners in peril. One rescue strategy utilizes a submarine escape capsule commonly referred to as a surfacing rescue container (SRC). Although SRCs have been used in several submarine designs over the last four decades, the United States has never adopted the underlying strategy. This paper recognizes the SRC concept as one of the most effective means of rescue, and proposes a modular SRC concept design (LSRC) that utilizes a modified Trident II D-5 missile tube as its host. The design is intended for use onboard the US Navy's next-generation ballistic missile submarine (SSBN) but may be back-fitted on current US Navy Ohio Class and UK Royal Navy Vanguard Class submarines with significant alterations. Technical analyses include a minimum weight design approach for internally stiffened right circular cylinders exposed to external hydrostatic pressure, an analytical and numerical structural analysis of imperfect ring stiffened cylinders with end-caps, and a seakeeping analysis for SRCs of cylindrical shape.

Enhancing the spatial awareness of trainee submariners using 3D game engines as training tools

Three-dimensional (3D) gaming technologies can be used to create experiential based learning environments that realistically represent real world places. Such learning environments are well suited for cognitive tasks that include navigation and locomotion in three dimensional environments (Munro et al., 2002). This paper reports on a study to explore the effectiveness of the Location and Scenario Training System (LASTS) to enhance the spatial awareness of trainee submariners. The simulation was used to engage participants in a simplified version of the 12 point safety round (12 PSR) performed inside the main generator room (MGR) on a Royal Australian Navy Collins class submarine. Results indicated that LASTS trainees performed the simplified 12 PSR more effectively than non-LASTS trainees. There was also some evidence to suggest that LASTS trainees possessed a comparatively better overall spatial representation of the MGR, including the development of higher order spatial knowledge.

Morbidity rates on Vanguard Class submarines during nuclear deterrent a retrospective review over 13 years

The submarines responsible for the United Kingdom's nuclear deterrent have carried a junior doctor as their medical officer since the program's inception. The Vanguard Class of submarine carries approximately 150 men and deploys for about 3 months at a time. One of the central tenets of submarine operations is to remain undetected and as such the submarine will only surface in an emergency, which may include the evacuation of casualties. The prime reason for carriage of a medical officer is to mitigate against the need to evacuate personnel for medical reasons. We examined the medical section of the patrol reports submitted upon completion of each patrol over a 13 year period to determine both the rates of medical and dental attendance onboard and also the occurrence of potential medical threats to patrol integrity. The most common reasons for attendance were dermatological and musculoskeletal, consistent with previous studies of this population and working environment. There were few dental cases due to the high rates of dental fitness in the pre-sailing crews. Patrol threatening cases occurred at a rate of approximately 1 per 3 patrols, with acute appendicitis being the most common presentation. This progressed to evacuation at a rate of 1 per 15 patrols, with the successful onboard management in 79% of cases. The junior doctor onboard has limited monitoring equipment and formulary, no diagnostic equipment, basic surgical equipment and no opportunity to seek senior advice, and is therefore reliant on clinical judgement. Despite the limitations placed on the doctor on board these submarines they have proven to be effective in reducing the rate of medical evacuation.