Watertight Doors Research Articles

The Impact of the new DMS-1030 Stability Standard on the Future Design of Navy Ships

In 2022, the German BAAINBw launched a revised issue of their 1030-1 stability regulations for Navy surface vessels. The improvements of the revised code concerned (inter alia) a new stability criterion for minimizing the effect of parametric rolling combined with pure loss of stability on the wave crest and revised damage stability calculation assumptions, which mainly focus on the submergence of openings and a special treatment of watertight doors. The improvements of the code were found to be necessary to keep track of recent developments in IMO for commercial ships and to update the safety level represented by the code. At the same time, the revised code gives more freedom to the ship designer, a fact which may allow novel and more cost effective concepts of Navy Ships in the near future, provided, the evaluation of the stability according to the code takes place immediately during the very early design phase of the ship. The present paper gives insight into the important updates of the code and it demonstrates at the same time how the design of Navy Ships may benefit from the revised code, if it is applied throughout the very first design phase of the ship. The paper will further present an improved design regime for the early design stage.

The Role of Emergency Generator during Black-Out on the MV. Kelud

Emergency generator is an auxiliary machine that functions to generate electrical power to meet the electrical needs of the ship during an emergency (black-out). This research was conducted to find out what caused the black-out onboard KM. Kelud, how the role of the Emergency generator during a black-out, and how to maintain the emergency generator so that it is always ready when used. The research method that the author uses is a qualitative research method. Data collection is done through interviews and observations. The results obtained from this study indicate that the cause of the black-out on KM. Kelud is the entry of mud into the hull, causing the cooling system in the main engine to be disrupted and eventually black-out. The role of the emergency generator during a black-out is as a temporary source of electricity to run several devices, such as navigation equipment, ship lighting, fire alarm systems, sprinkle pumps, and watertight door systems. In order for the emergency generator to run according to its function, it must be carried out routine maintenance such as checking batteries, oil and lubricants, cooling systems, and periodic testing.

A framework for onboard assessment and monitoring of flooding risk due to open watertight doors for passenger ships

Post-accident safety of ships is governed by damage stability, affected by watertight subdivisions which limit accidental flooding. This is important for passenger ships with watertight doors (WTDs) often fitted in the bulkheads. Awareness of the ship flooding risk due to open WTDs and the conditions under which the associated risk level changes are prerequisites for proactive risk mitigation.Accident risk is often expressed as a combination of accident likelihood and its consequences. Current solutions for flooding risk mitigation often treat these elements separately, or the adopted metrics are based on quantities not allowing proper active control of risk.In this paper an attempt is made to fill this gap by introducing a novel concept for rapidly assessing the flooding risk onboard passenger ships, accounting for the two dimensions of flooding accidents. The likelihood part is based on the complexity of surrounding traffic, operational conditions, and human reliability assessment. The consequences are based on precalculated probabilistic damage stability results of ship survivability.The presented case studies indicate that active monitoring of flooding risk can increase the crew's situational awareness of the effect of open WTDs on the flooding risk, thus positively influencing the safety culture onboard the ship.

Implementation of High Reliability Organizing (HRO): The Inherent Vice of Stress, Fear, and Threat

Implementation of High Reliability Organizing (HRO): The Inherent Vice of Stress, Fear, and Threat

Sealing state monitoring of watertight door using fiber Bragg grating sensor with arc-shaped structure

The sealing state of the watertight door (SSWD) is important information for the safe operation of a ship. A monitoring method for the SSWD based on fiber Bragg grating (FBG) sensor is designed, which can monitor the opening and closing state of the watertight door in real-time. A highly sensitive and temperature-independent sensor is installed under the rubber of the watertight door, the relationship between the displacement of the door panel and the wavelength shift of FBG is linearly fitted with the sensitivity of about 314.511 pm / mm, and the error percentage with the finite element analysis is 6.22%. The watertight door is opened and closed many times, the results show that the sensor has good stability and reliability, and the opening state, closing state, and the degree of opening and closing can be accurately judged by the wavelength shift of FBG. At the same time, the sensor can also identify the foreign body within a certain range on the rubber surface.

Flood Risk Assessment of Metro System Using Improved Trapezoidal Fuzzy AHP: A Case Study of Guangzhou

Metro systems have become high-risk entities due to the increased frequency and severity of urban flooding. Therefore, understanding the flood risk of metro systems is a prerequisite for mega-cities’ flood protection and risk management. This study proposes a method for accurately assessing the flood risk of metro systems based on an improved trapezoidal fuzzy analytic hierarchy process (AHP). We applied this method to assess the flood risk of 14 lines and 268 stations of the Guangzhou Metro. The risk results validation showed that the accuracy of the improved trapezoidal fuzzy AHP (90% match) outperformed the traditional trapezoidal AHP (70% match). The distribution of different flood risk levels in Guangzhou metro lines exhibited a polarization signature. About 69% (155 km2) of very high and high risk zones were concentrated in central urban areas (Yuexiu, Liwan, Tianhe, and Haizhu); the three metro lines with the highest overall risk level were lines 3, 6, and 5; and the metro stations at very high risk were mainly located on metro lines 6, 3, 5, 1, and 2. Based on fieldwork, we suggest raising exits, installing watertight doors, and using early warning strategies to resist metro floods. This study can provide scientific data for decision-makers to reasonably allocate flood prevention resources, which is significant in reducing flood losses and promoting Guangzhou’s sustainable development.

Accident susceptibility index for a passenger ship-a framework and case study

The continuous monitoring and assessment of operational vulnerability and accident susceptibility of passenger ships is crucial from the perspective of ship and passenger safety. Despite the existing solutions for vulnerability monitoring, stemming mainly from watertight door operations, a comprehensive framework for accident susceptibility assessment and monitoring is missing in the literature.Therefore, this paper offers a straightforward approach, utilizing heuristics rooted in the solid foundations of the first principles related to human performance. The proposed approach allows the evaluation of accident susceptibility of a ship in operation involved in open-sea and coastal navigation. The framework presented is based on observable and relevant factors, known to affect the navigator's performance, and as a consequence accident probability. The layout of the framework as well as the parameters of the developed model are based on literature survey in maritime and aviation domains, knowledge elicited from maritime experts and extensive simulations with the use of an in-house developed ship-ship encounter simulator. Subsequently, the model is applied to selected case studies, involving two distinctive ship types, namely a large cruise ship and a RoPax vessel.The results obtained for the case study presented in this paper reveal that most of their time the analyzed ships operate with negligible accident susceptibility (87%), while 1% of the cases are labelled as very high accident susceptibility. The remaining share of 12% is distributed among low, moderate and high values of accident susceptibility. The results are in line with earlier studies conducted in the same area but adopting different methods.The proposed solution can be applied as an onboard decision support tool, evaluating the operational accident susceptibility and vulnerability, thus increasing the crew's situational awareness. Additionally, it can be applied to historical data, allowing ship navigational safety diagnosis and implementation of appropriate countermeasures.

Watertight Door Control System on A Ship using Profinet IO

The paper is to deal with the analysis of Profinet IO networks based on the design of a watertight door control system on a passenger ship. The analysis was based on modernization of existing watertight door system installed on a ship. The currency system on ship it use old PLC like S7-200, receive and send date only serial communication. In laboratory on University conditions the same network using two controls company Siemens PLC S7-1214 DC/DC/DC and simulated HMI write on WinCC was recreated and modified with Profinet IO standard. The authors propose a novel watertight door control system using two controllers and a touch panel HMI. The control algorithms have been written in LAD language with use norm SOLAS about list alarm. Program it was write in TIA Portal with use Function blocks (FB) with Block Date (DB) and Function (FC). When designing the laboratory bench, the authors based their assumptions on the actual solutions used on the Balmoral passenger ship. Tests were carried out on parameters related to dimensions, including the length of cables between communication modules of controllers, giving in results the actual lengths of cables in the current system and the one proposed in this work. Then, the possibility of data exchange between the two controllers and the visualization of the simulated KTP 1200 panel was examined. The operation of the software was verified, including its optimization for the correct operation of the entire system. The final part of the paper, after verifying the performance of the system in three steps, an analysis of the current system and the novel solution based on Profinet IO network is given.

Maritime operational risk management using dynamic barriers

ABSTRACT The safe operation of any vessel is challenged by the constraints posed through design, proper maintenance and operation of the available safety barriers ensuring their effectiveness. This requires a direct linkage between barrier performance and operational risk management accounting for barrier degradation and ensuing corrective actions. This paper demonstrates a comprehensive approach to Dynamic Barrier Management, by illustrating how barrier performance information and their respective functions is (a) collated, (b) aggregated through parametric models for identifying barrier relative importance, function criticality and in defining a set of key safety indicators, and (c) is intuitively visualised for providing real-time guidance to crew and shoreside management. The approach is demonstrated by considering watertight doors as Dynamic Barriers preventing excessive transient- and progressive-flooding on a cruise vessel during operation. It is further discussed how these methods can be generalised into a framework, enabling operational risk management and subsequent decision support.

Flood Risk Assessment of Subway Systems in Metropolitan Areas under Land Subsidence Scenario: A Case Study of Beijing

Flooding is one of the most destructive natural events that severely damage the ground and inundate underground infrastructure. Subway systems in metropolitan areas are susceptible to flooding, which may be exacerbated when land subsidence occurs. However, previous studies have focused on flood risk evaluation on regional/watershed-scales and land subsidence monitoring in plains, instead of on subway flood risk evaluation and how land subsidence aggravates the flood risk in subway systems. Using the proposed risk indicators and field survey data, we present a method assessing the flood risk of metropolitan subway systems under a subsidence condition based on the fuzzy analytic hierarchy process (FAHP) combined with a geographic information system (GIS). We use the regional risk level within the 500 m buffer zone of the subway line to depict the flood risk of the subway system. The proposed method was used to evaluate the flood risk of the Beijing subway system. The results show that the flood risks of the Beijing subway show a ring-like distribution pattern—risk levels decreasing from the central urban area to the suburbs. Very high and high risks are mainly located within third and fourth ring roads, accounting for 63.58% (29.40 km2) and 63.83% (81.19 km2) of the total area. Land subsidence exacerbated the Beijing subway system’s flood risk level—the moderate to very high risk increased by 46.88 km2 (16.33%), indicating that land subsidence is an essential factor affecting the flood risk level of subway systems. In addition to enhancing flood warnings, future subway flooding could be reduced by elevating the height of the stations’ exit (entrance) and installing water stop plates and watertight doors. This study is of great significance for flood warning and prevention in the Beijing subway system; it provides a theoretical basis for flood risk evaluation in other metropolitan areas.

Examination and analysis of the water tightness of watertight doors in nuclear facilities (Water tightness of the watertight doors beyond design conditions)

Examination and analysis of the water tightness of watertight doors in nuclear facilities (Water tightness of the watertight doors beyond design conditions)

함정용 Sliding Type 수밀문의 구조안정성 평가

함정용 Sliding Type 수밀문의 구조안정성 평가

Validating Human Behavior Representation Model of General Personnel During Offshore Emergency Situations

With the advancement of simulation-based training, intelligent agents that can display human-like behavior have become common. From military combat simulations to nuclear power plant simulation, agents have been widely used to facilitate team training (as team mates, opponents, or both). Credibility of these agents is vital to ensure a sound training process. Credibility of the agents largely depends on the credibility of the underlying human behavior representation (HBR) model. This is why validation of the HBR model is necessary to ensure realistic agent behavior. However, the non-deterministic nature of the HBR and the subjectivity in experts’ judgment during the validation process make HBR model validation more challenging compared to physics based models. This paper presents the validation process of an HBR model of general personnel created for use in an offshore emergency training simulator. Three types of agents (naive, in-between, and ideal) are created in the simulator using the HBR model. The paper discusses the use of empirical evidence as referents, along with subject matter experts. A two-level three factor experiment was conducted using 36 participants. Several performance metrics were collected during the experiment, including route selected for evacuation, time to muster, time spent running, interaction with fire doors and watertight doors, interaction with hazards, and reporting to the muster station. Data collected during the experimental study have been used in this paper to demonstrate how the use of empirical evidence can facilitate HBR validation. High-level tasks performed during HBR validation are discussed in detail. Special emphasis is given on acceptability criteria testing to ensure that the HBR model performs adequately under different operating conditions. Results show that the proposed HBR model meets the acceptability criteria requirement for all types of agents. In general, the ideal agents exhibited safe behavior during offshore emergency egress, whereas the naive and in-between agents showed erroneous behavior at times. For example, during the simulation runs of a critical emergency scenario where the primary egress route was obstructed by a hazard, the ideal agents either waited and listened to the public address announcement and followed an alternative egress route (60% cases), or they initially chose their preferred route but re-routed immediately after encountering the hazard (40% cases). In all cases, the in-between agents started with their preferred route and re-routed after encountering the hazard, and the naive agents proceeded with their preferred route even when the route was compromised.

High-precision machining in the shipbuilding industry. Applicability and advantages of electro discharge machining technology

ABSTRACTThis research shows the applicability and advantages of the electro discharge machining (EDM) technique in the shipbuilding industry. This process allows the machining of high strength materials, such as some of the steels used in the naval sector for key parts of the ship's structure. Likewise, this technique obtains high-precision surface finishes and highly complex geometries, which are of great interest in pieces destined for waterproofing, such as hull passages or watertight doors, or components that require a complex geometry such as those destined for lubrication systems in bearings and the stern tube. In this work the results obtained in the laboratory will be presented, as well as a numerical model that allows the simulation of the process and its optimisation under different material and surface finishing conditions. The conclusions reached in this work have been oriented to the application of this advanced machining process to the shipbuilding industry.

Modern Modeling of Water Hammer

Abstract Hydraulic equipment on board ships is common. It assists in the work of: steering gear, pitch propellers, watertight doors, cargo hatch covers, cargo and mooring winches, deck cranes, stern ramps etc. The damage caused by transient flows (which include among others water hammer) are often impossible to repair at sea. Hence, it is very important to estimate the correct pressure runs and associated side effects during their design. The presented study compares the results of research on the impact of a simplified way of modeling the hydraulic resistance and simplified effective weighting functions build of two and three-terms on the estimated results of the pressure changes. As it turns out, simple effective two-terms weighting functions are able to accurately model the analyzed transients. The implementation of the presented method will soon allow current automatic protection of hydraulic systems of the adverse effects associated with frequent elevated and reduced pressures.

Development and verification of wall-flap-gate as tsunami inundation defence for nuclear plants

A wall-flap-gate is automatic watertight door, and it works by buoyancy without powered machineries and human operations. In the Tohoku Earthquake tsunamis, serious damages were caused by inundation from ventilators of outer walls in power plants. The wall-flap-gate is estimated to be effective in keeping sustainability of nuclear plants against extreme tsunamis. The present study examines the hydrodynamic characteristics of the wall-flap-gate by hydraulic model experiments and verifies its capability of flood prevention for nuclear plants through various prototype tests.The experimental results proved that the wall-flap-gate had sufficient strength, watertightness, and durability against tsunamis and that its motion was not disturbed by debris. The viability of the wall-flap-gate as an inundation defence structure for nuclear plants was confirmed through this study. As a result, practical wall-flap-gates are installing on Hamaoka nuclear power station in Shizuoka prefecture, Japan.

Component fragility for use in PSA of nuclear power plant

The accident of Fukushima nuclear power plant (NPP) underscores the necessity of conducting probabilistic safety assessment (PSA) of an NPP against the hazards caused by external events of natural origin. One of the important tasks of an external event PSA (EE-PSA) of an NPP is determination of component fragility. The fragility of a component is the probability of its reaching a limit state condition on a particular level of demand caused by the hazard. The seismic fragility of component is expressed by means of a double lognormal model with three parameters – the median ground acceleration capacity Am, random variability βR and uncertainty βU in the median capacity. There are direct and indirect methods to calculate fragility parameters Am, βR and βU. Direct method involves either analysis or testing. Indirect method is experience based method that maximizes the use of past experience in conjunction with plant walk down. The parameters for wind fragility Vm, βR and βU are estimated for different SSCs using design data (e.g. wall thickness, reinforcement, and anchorage) and variability associated with the wind response and capacity. The parameters for flood fragility Hm, βR and βU are also estimated for different structures, systems and components (SSCs) using design data and variability associated with the flood response such as inundation depth and capacity such as installation height. However, it generally shows more cliff-edge shape without any special barriers (e.g. protective walls, water-tight doors and sealing countermeasures). It means that flood fragility is highly path-dependent and thus flood hazard is influenced by barriers’ fragility. The paper reviews the available open literature and summarizes the development of methods for deriving the fragility parameters of NPP components for use in PSA against seismic ground motion, wind and tsunami induced flood hazard. The paper also briefly discusses the component fragility for external event PSA of multiple NPP units at a site for natural hazards like earthquake, wind and flood. The state-of-the-art of seismic fragility analysis for NPP component is in matured level, while that of flood hazard in early stage of development and wind hazard in nascent stage.

Iceberg risk in theTitanicyear of 1912: was it exceptional?

At 2340h local time (0310 GMT) on the cold, moonless, night of 14 April 1912, near 41°47 N, 49°55 W (Marine Accident Investigation Branch, 1992), the crow’s nest lookouts on board RMS Titanic sighted a large iceberg only 500m ahead. Despite quick action on the bridge to slow the ship, and turn to port, as well as the closing of the water-tight doors, the slow response of a large vessel meant that the iceberg still struck the ship aft of the bows. Some 100m of her hull below the waterline buckled, allowing water to flood into the ship across several compartments (Howells, 1992). In little more than two and a half hours she had sunk, with the loss of 1514 lives (Havern, 2012). A distress call requesting assistance was transmitted only 20 minutes after the collision, and RMS Carpathia turned and raced towards the Titanic at a speed of 17.5kn, 20% above her normal maximum speed. However, she did not arrive at the scene until around 0330h (15 April; 0700 GMT), by which time only 710 people remained to be rescued from the 20 lifeboats that had been able to be launched (Howells, 1992). The weather, ice conditions and time of year combined to increase the iceberg hazard on that fateful day. High pressure had dominated the mid-latitude, central Atlantic for several days (Howells, 1992) and by the time of the collision a ridge linking two high-pressure centres over Nova Scotia and the south of Ireland extended across the entire Atlantic (Figure 1). This resulted in northnorthwest winds transporting nearfreezing air from northeast Canada over the western Atlantic south of Newfoundland (Figure 1). These winds and temperatures, assisted by the prevailing southward flow of the ocean’s Labrador Current on the Grand Banks, led to transport of icebergs and sea ice further south than is currently normal for the time of year, but not beyond the known limits to icebergs during the twentieth century (Figure 2). However, note that Figure 2. The average sea-ice limit for April 1979–2013 (dotted), a typical Newfoundland maximum sea-ice limit for the early twentieth century (dashed and denoted as 1912; from Hill and Jones, 1990) and the maximum iceberg limit for 1900–2000 are shown, in addition to the 48°N line. The location of the Titanic is shown by an ‘X’. The blue shading shows depth, with the lightest blue denoting the continental shelf (<100m depth). Figure 1. Sea-level pressure and air-temperature chart for 0000 GMT, 15 April 1912, taken from the ensemble mean of the twentieth century reanalysis (Compo et al., 2011). The location of the Titanic is shown by an ‘X’.

Structural Design and Realization of Wheel-Legged Obstacle Crossing Vehicle

High threshold of watertight door makes it difficult for materials transporting in the cabin by ordinary equipment. So, an un-powered mechanical structure is presented by the thesis, which can cross watertight threshold easily. On the basis of this structure,an obstacle crossing vehicle is designed for materials transporting in cabins.

On the Use of Wireless Technologies for Shipboard Monitoring Systems

Current shipboard monitoring systems use extensive lengths of cables to connect sensors to control units. Replacing wired connections by wireless ones may be an efficient solution to reduce the ship weight and cost. Ships are characterized by a specific metallic environment which can severely decrease the efficiency of wireless networks due to signal attenuation and multipath effects. In this paper, we present a feasibility study of a Wireless Sensor Network (WSN) using ubiquitous technologies on board vessels. A measurement campaign has been conducted on board a ferry to investigate the radio propagation challenges of wireless communications in this particular environment. Path loss models have been obtained for typical shipboard environments. Engineering rules concerning the placement and the number of communication nodes needed to cover the decks and maintain the network connectivity have been determined. Based on these results, an IEEE 802.15.4 compliant WSN has been tested on board the same ferry. Sensor nodes have been placed on the four decks of the ferry and the base station has been placed in the control room located in the bottom deck. Results show an excellent performance with respect to transmission ratio of sensor nodes and a significant connectivity between nodes located in different compartments and decks separated by metallic watertight doors.