FAULT TREE ANALYSIS (FTA) - FORMAL SAFETY ASSESSMENT (FSA) IN SHIP REPAIR INDUSTRY A MADE EASY APPROACH

Fault tree-Formal Safety Assessment (FT-FSA) is the premier scientific method that is currently being used for the analysis of maritime safety and for formulation of related regulatory policy. To apply FSA in this paper, all five steps are considered and critical information highlighted in each step as reviewed in the literature. A novel 15 steps approach of FT-FSA is introduced in the systematic accident scenario considered in this study as emergent phenomena from variability and interactions in shipyard (considered as a complex system).The results of this paper will be useful for guidelines and regulatory reforms in ship repair industry as demonstrated by identifying ‘fall from height in ship repair occupational hazards’ for recommendation in decision making.

Technological features of repair cracks in ship plates by comb cutting method

Ремонт трещин в судовых пластинах является наиболее ответственной и сложной операцией Задача получения заданных размеров проплава с обратной стороны свариваемого металла резко усложняется в тех случаях, когда доступ к обратной стороне шва затруднен или вообще невозможен, выполнение двухсторонних сварных швов на наружной обшивке корпуса судна, в большинстве случаев для доступа к поврежденным районам, приводит к увеличению числа сопутствующих работ по демонтажу (монтажу) оборудования и влияет на нормативные сроки ремонта судов, в том числе и при стоянке судов в доке. В данной работе излагаются результаты исследования эффективности технологии ремонта трещин, в судовых пластинах, путем ориентации сварочной ванны вдоль плоскости повреждения, за счет гребенчатой разделки поврежденного района с различной геометрией кромок. Представлены результаты аналитического исследования и факторных экспериментов оценки прочности сварных соединений с различной геометрией гребенчатой разделки, при односторонней сварке, с использованием различных сварочных материалов и варьировании режимов сварки. Приведены результаты металлографического исследования (на макрошлифах) полученных сварных соединений. Предложены технологически эффективные, для практического применения в судоремонте, параметры гребенчатой разделки трещин в судовых пластинах. Repair of cracks in the ship plates is the most responsible and complex operation The task of obtaining the specified dimensions of the melt on the reverse side of the welded metal is sharply complicated in cases where access to the reverse side of the seam is difficult or even impossible, the implementation of double-sided welds on the outer skin of the hull of the vessel, in most cases for access to damaged areas, leads to an increase in the number of related works on the dismantling (installation) of equipment and affects the normative terms of repair of vessels, including when ships are parked in the dock. This paper presents the results of the study of the effectiveness of the technology of repair of cracks in the ship plates, by orienting the welding bath along the damage plane, due to the comb cutting of the damaged area with different geometry of the edges. The results of analytical research and factor experiments assessment of the strength of welded joints with different geometry of comb cutting, with one-sided welding, using different welding materials and varying welding modes. The results of metallographic research (on macro-grinds) of the obtained welded joints are given. Technologically effective parameters of comb cutting of cracks in ship plates are proposed for practical application in ship repair.

Evaluation of the durability of mastic deck covering based on polymer composites in the range of operating stresses and temperatures

The urgency of anticorrosive protection issues of ship hulls, deck structures, mechanisms, etc., as one of the main problems of the naval, is noted. One of the options for its effective solution is the use of coatings based on various polymer-composite materials. The authors substantiate the need for a preliminary assessment of the reliability and durability of such coatings, taking into account high humidity and aggressiveness of the operating environment, the corrosion of the repaired surfaces, the cyclic effect of stresses and alternating temperatures, etc. Proceeding from this, using the example of multicomponent polymer-composite compositions of the “Sprut” type, methodological approaches to the study of the polymer-composites durability for ship repair are considered. Their comparative characteristics are given. A mathematical model for assessing the durability of polymer-composite materials and coatings based on them is described, and the experimental studies’ results of their durability under static and cyclic stress in the operating temperature range are presented. The obtained results of theoretical and experimental studies are important for development of the methodological approaches to increasing the durability of mastic deck coatings based on polymer composite materials and the development of practical guidelines for the use of adhesives in shipbuilding and ship repair. The research results make it possible to develop new and improve the adopted technologies for the use of protective coatings on the structures of ship hulls and deck structures. Thus, the problems of the water transport operation, associated with the anti-corrosion protection of ship hull and deck structures and their repair, can be solved.

Fiberglass as an alternative to metals in ship repair

The article presents the intermediate results of a study carried out to determine the prospects for reducing the metal consumption of ship repair. The area of research is ship repair, in particular, the repair of hulls and superstructures of metal ships, and the object is fiberglass used in the repair, in particular, their strength and durability. The studies were carried out using well-known methods - spontaneous peeling, shearing, limiting states. The results obtained made it possible to establish that the use of fiberglass plastics can reduce the metal consumption of ship repairs by three times. In addition, the article describes a method for calculating the thickness of a fiberglass coating, which is equivalent in strength to a metal backup, and also provides expressions for evaluating the calculated resistance of the coating, which determines its durability. In conclusion, it was concluded that it is necessary to expand the study area of the applicability of fiberglass during the repair of ships, not limiting it only to such obvious objects of repair as the hull, superstructure, pipelines.

Assessment of the Radiation and Health Physics Situation in the Area of Ship Repair Enterprises in Kamchatka Krai

The objectives of the study are to examine the radiation and health physics situation in the area of ship repair enterprises servicing ships with nuclear power installation; to assess its possible impact on the environment and the population. Materials and research methods. The study of radiation and health physics situation on the territory was conducted by walking gamma survey using portable gamma spectrometric complexes MKS-01A "Multirad-gamma" and MKS-AT6101C. Gamma-spectrometric and radiochemical methods of analysis were used to determine the specific activity of man-made and natural radionuclides in environmental samples. Results of the study and their analysis. Practical medical and hygienic measures to study the radiation and health physics situation were carried out in 2019. It was found that the ambient equivalent dose rate in the areas of ship repair enterprises is at the level of regional values and does not exceed 0.12 μSv/h. Radionuclide specific activity in the soil of the surveyed areas does not exceed 4.5 Bq/kg — for 90Sr and 12 Bq/kg — for 137Cs, which does not exceed the established norms for unrestricted use of solid materials. Radionuclide content in the sea water samples taken in the area of closed administrative territorial unit Krasheninnikov Bay does not exceed on average: for 137Cs — 7 mBq/L, for 90Sr — 2.1 mBq/L. When comparing the results obtained with the official data on the radionuclide content in the water of Avacha Bay (90Sr up to 2.08 mBq/L at the annual average of 1.14 mBq/L), we may state that they are at the same level as the regional ones. Radionuclide content in bottom sediment samples varies within the following limits: for 137Cs — from 0.14 to 3 Bq/kg, for 90Sr — from 0.11 to 1.5 Bq/kg and is similar to the general values for soil samples. Thus, the radiation and health physics characteristics of the study area vary little and remain practically at the level of the results of studies conducted in 2014-2015. The content of man-made radionuclides in the samples of environmental objects is at the level of average values typical for the region. Potentially radiation-hazardous works carried out in 2019 at enterprises of closed administrative territorial unit Vilyuchinsk had no reliable radiation impact on the environment and population.

Evaluating the effectiveness of a shipping company environmental protection

В статье сформирована структура показателей оценки безопасности для транспортных средств морского и внутреннего водного транспорта. Каждый компонент структуры включает от двух до пяти составляющих. Обоснованы группы оценочных критериев: функциональные, экономические, социальные, экологические и информационные. Установлено, что в качестве основных критериев безопасности водных транспортных средств целесообразно рассматривать значения концентраций опасных веществ (экологическая безопасность), уровень шума на судах (экологическая безопасность), уровень аварийности и травматизма на судне (функциональная безопасность), уровень ущерба от аварий и инцидентов на судне (функциональная безопасность) и уровень риска, как интегральный критерий безопасности. Показаны причины возникновения технических аварийных ситуаций, которые связаны с недостатками в организации работы судовых экипажей, с низкой квалификацией личного состава, с ошибочными действиями береговых служб управления, технического обслуживания и судоремонта. Утверждается, что для получения количественных показателей безопасности водной транспортной системы необходимо разработать модели безопасности для её элементов с учетом разнообразных ситуаций и определить вероятностные характеристики частных событий (аварий и инцидентов), входящих в модели безопасности. The structure of safety assessment indicators for sea and inland water transport vehicles is formed in the article. Each component of the structure includes from two to five components. The groups of evaluation criteria are justified: functional, economic, social, environmental and informational. It is established that as the main criteria for the safety of water vehicles, it is advisable to consider the values of concentrations of hazardous substances (environmental safety), the noise level on ships (environmental safety), the level of accidents and injuries on the ship (functional safety), the level of damage from accidents and incidents on the ship (functional safety) and the level of risk as an integral safety criterion. The reasons for the occurrence of technical emergencies are shown, which are associated with shortcomings in the organization of the work of ship crews, low qualification of personnel, with erroneous actions of the coastal management services, maintenance and ship repair. It is argued that in order to obtain quantitative indicators of the safety of a water transport system, it is necessary to develop safety models for its elements taking into account various situations and to determine the probabilistic characteristics of particular events (accidents and incidents) included in the safety models.

Bidding Models Analysis on Ship Repair Projects (Friedman and Ackoff & Sasieni Models)

The existence of a ship project carried out with a tender system by the LPSE allows all shipyard industries to bid on the project, this causes the chances of winning to become smaller, the determination of the tender price greatly determines the size of the profit that can be obtained and the percentage of the possibility of winning the project in a shipping industry. Therefore, the strategy of determining the bid price is very important. The statistical method used is multi discrete distribution, and multi normal distribution, while the bidding model uses Friedman (1956) and Ackoff & Sasieni (1968) models. The results obtained the best bid price strategy to win an auction or tender is the model that produces the lowest optimum mark-up, namely the Friedman model with multi normal distribution, while for Ackoff & Sasieni it produces a higher bid than the Friedman model except in certain company conditions.