Watertight Bulkheads Research Articles

Floodable length analysis of a container vessel using computer aided design

The floodability of a container vessel is investigated to determine the maximum volume of compartments that can be flooded without causing the container vessel to capsize. In this project, Maxsurf modeler was used for the hull design and Maxsurf stability enterprise for the floodable length analysis of a container vessel at several displacements, number of transverse water tight bulkheads and its positions from AP to FP and a constant permeability value for the compartments. Floodable length is the preliminary check on damage survival. It is used at the initial concept design phase because it is faster than a full damage stability analysis, it checks if the vessel has sufficient buoyancy to sustain damage and stop from sinking straight to the bottom. Maxsurf Enterprise marine design software is used to determine the results. The output of the analysis shows a floodable length curve and the curves that represent different displacements, if a displacement line is below the allowable floodable length of a compartment then the vessel will not survive damages but if the line is above the allowable floodable length then the vessel will survive damages. The result also shows that it is easier for the vessel to survive heavily loaded conditions with more compartments.

Application of Buoyancy Support System to Secure Residual Buoyancy of Damaged Ships

SOLAS (Safety of Life at Sea), which was first enacted in 1914 as a result of the Titanic disaster, presents mandatory requirements for ship safety, such as the adoption of watertight bulkheads. However, ship accidents continue to occur despite the development and application of numerous safety technologies. In the case of a marine accident, the risk of sinking or capsizing due to flooding can be reduced by subdividing the watertight area, but shipbuilding costs, the weight increase for light ships, and the intact stability of the vessel must be considered together. For this reason, in this study, a BSS (buoyancy support system) was designed in accordance with ISO 23121-1 and ISO 23121-2. The characteristics of watertight and non-watertight spaces were reviewed and the BSS was implemented for a small car ferry. By applying additional safety technologies while securing economic feasibility in terms of ship construction and operation, an alternative to reduce the loss of human lives, environmental damage, and property losses in the case of a ship accident was proposed.

Numerical Simulations on the Flooding into a Damaged Cabin with a Flexible Bulkhead Based on the Mixed-Mode Function-Modified MPS Method

Floodwater entering the damaged cabin and impacting the bulkhead can cause damage to the watertight compartment and affect the survival of the ship. The elastic deformation of the bulkhead can slow down the impact and affect the flow field, which affects the hydrodynamic distribution inside the cabin. In this work, numerical simulations on the flooding phenomena into the damaged cabin with various stiffness, watertight bulkheads are carried out by using the mixed-mode function-modified moving particle semi-implicit (MPS) method, with the objective of investigating the influence of the stiffness of the watertight bulkheads on the structural impact load. Firstly, the numerical model based on the MPS method is set up to predict the dam-break wave impact load on an elastic plate and compared with the experimental measurements to verify the feasibility of the method. Then, the evolution of the flooding process of the damaged cabin with four different stiffnesses are simulated and the impact pressure on the bulkhead is predicted and compared. It is found that the flexible watertight bulkheads not only can reduce the peak pressure acting on it, but also have an effect on the hydrodynamic pressure distribution of the entire cabin. This implies that properly selected stiffness and material properties of watertight bulkheads can mitigate the impact of flooding on the damaged cabin’s bulkheads.

High-Expansion Foam: A Risk Control Option to Increase Passenger Ship Safety during Flooding

In naval architecture, the standard way adopted to reduce the risk of potential loss of life for passenger ships after an accident is via regulations. In case of flooding, this explicitly implies the introduction of fixed watertight bulkheads, permanently modifying the internal ship’s layout. Damage stability regulations constantly aim at higher safety standards; therefore, the layout reconfiguration of an existing vessel may be essential to meet new requirements, leading to higher costs for retrofitting. Furthermore, increasing fragmentation of the internal layout has a physical limit, neglecting the possibility to elevate standards above a particular upper limit. In this view, innovative solutions give the chance to exceed such a limit. The present work describes the advantages of high-expansion foam application for passive and active protection from flooding events. The possibility to have a material granting sufficient water tightness allows installing fixed or deployable barriers that increase the safety level of the ship. Here, besides the description of the foam characteristics, the application on a reference passenger ship highlights the advantages of passive and active foam barriers to limit flooding and drastically reduce the risk of loss of lives. The changes in the limiting stability margins required by regulations and the analysis of dynamic flooding simulations for specific damage cases demonstrate the benefits of foam installation onboard passenger ships as a risk control option.

A Collaborative Optimization Algorithm for Ship Damage Stability Design

The damage stability of ship is a key performance metric in ship design. The challenge of damage stability optimization is a complex calculation process with multi scene dynamic inflow simulation relying on the cooperation of ship design software such as NAPA. Our work is to establish a collaborative optimization framework to effectively coordinate reinforcement learning (RL) with particle swarm optimization (PSO) and NAPA. The collaboration of RL and PSO realizes the update direction selection of watertight bulkhead position scheme. The collaboration of PSO and Napa promotes the iterative process of watertight bulkhead position and damage stability value A. The experimental results show that compared with the traditional damage stability optimization method, the collaborative optimization method improves the damage stability by 2.36% and reduces the calculation time significantly.

PARAMETRIC FORMULATION OF THE FLOODABLE LENGTH CURVE: APPLICATION CASE TO OFFSHORE PATROL VESSELS

The residual buoyancy of vessels after damage has a fundamental role in their survivability and it is implemented through adequate ship internal subdivision. Traditionally the number and the position of transverse watertight bulkheads are selected for most ships early in the design phase by means of the “floodable length curve” coupled with the concept of “margin line”. However, for naval vessels, it is more and more common during the acquisition process to explore a wide domain of feasible ships, identified with the assistance of automated processes and assessed also in terms of capabilities, among which is survivability. The generation and the comparison of a considerable number of different ship configurations is very time consuming. Therefore recourse to a parametric expression of the floodable length curve is considered to be a very efficient approach and would thus enable characterisation of the ship, in terms of survivability performance. In this paper such an approach is presented, using an offshore patrol vessel (OPV) as the case study.

Постановка и решение задачи проектирования рамного набора поперечной водонепроницаемой переборки крупнотоннажного контейнеровоза с использованием оптимизационно - поисковых процедур и нормативных требований правил DNV-GL

Поперечные переборки крупнотоннажных контейнерных судов представляют собой сложные конструкции, при проектировании которых обычно используется методология проверочного расчета на основе метода конечных элементов (МКЭ). Для создания конечно-элементной модели необходимо знать размеры всех элементов конструкций, входящих в состав переборки. Поэтому такой подход к проектированию является итерационным, что обуславливает высокую трудоемкость процесса проектирования. На ранних стадиях проектирования размеры конструкций поперечных переборок контейнеровоза могут быть быстро и достаточно точно оценены на основе аппарата нелинейного программирования, относительно простой модели составной (конструктивно-ортотропной) пластины и нормативных требований Правил классификационных обществ. Такой подход применяется в Российской практике при проектировании двойных конструкций типа двойное дно или понтон плавучего дока. В статье предложено решение задачи проектирования рамного набора поперечной переборки крупнотоннажного контейнеровоза на нагрузки от контейнеров, действующие на переборку при качке судна. Конструкция переборки приводится к условной модели «коффердамного» типа. Затем используется методика приведения составной «конструктивно-ортотропной» пластины к изотропной пластине с несколько иным соотношением сторон, но с такими же параметрами изгиба. Это позволяет применить существующие табличные данные для определения расчетных изгибающих моментов и перерезывающих сил, которые после аппроксимации представляются в виде полиномов – аналитических зависимостей. Показана постановка оптимизационно-поисковой задачи математического программирования. Целевая функция – характеристика массы рамного набора. Ограничения задачи формируются на основе нормативных требований DNV-GL и математических зависимостей модели составной пластины. Для решения задачи используется инструмент MS Excel «Поиск решения» Представлены результаты тестового проектного расчета применительно к конструкции крупнотоннажного контейнеровоз с контейнерной вместимостью 18 тыс. TEU. Сопоставление результатов проектирования с оригинальными расчетами фирмы – проектанта показали удовлетворительное соответствие. The transverse bulkheads of the large container vessels are complex structures that are commonly designed using the finite element method (FEM) verification methodology. To create a finite element model, it is necessary to know the dimensions of all structural elements of the bulkhead. Therefore, this approach to design is iterative, which leads to a high complexity of the design process. At the early stages of design, the dimensions of the structures of the transverse bulkheads of a container vessel can be quickly and accurately estimated based on the nonlinear programming technique, a relatively simple model of a composite (structural-orthotropic) plate, and the regulatory requirements of the Rules of Classification Societies. This approach is used in practice in Russia when designing double structures such as a double bottom or pontoon of a floating dock. The article proposes a solution to the problem of the transverse bulkhead web frames designing in application to a large-tonnage container vessel for loads of containers acting on the bulkhead when the vessel is moving on the waves. The bulkhead structure is reduced to the conditional "cofferdam" type model. The technique is used to reduce a composite "structurally-orthotropic" plate to an isotropic one with a slightly different aspect ratio, but with the same bending parameters. This allows applying the existing tabular data to determine the design bending moments and shear forces, which, after approximation, are represented as polynomial analytical dependencies. The statement the optimization-search problem of mathematical programming is shown. The goal function is the characteristic of the bulkhead's webs mass. The constraints of the problem are formed on the DNV-GL regulatory requirements and mathematical relationships of the composite plate model. MS Excel tool "Solver" is used to solve the problem. The results of a test calculation are presented as applied to a large-capacity container ship with container capacity of 18000 TEU. Comparison of the design results with the original calculations of the designer’s company showed satisfactory agreement.

Improvement of the Welding Process for Fillet Air Test for the Biggest Taiwan Shipyard

During ship block construction, watertight bulkheads weld of every cabin of ships need to undergo stress testing according to the tanks’ test plan. Every incomplete bulkhead cannot be sprayed in order to protect them after sandblasting; this seriously affects the process of construction. Therefore, the issue of this study is to maintain the integrity of the painting quality and reduce the destruction of the paint, ship-building personnel seek how best to complete the block operation. The aim of this project is to improve the recent watertight bulkheads fillet air test operations in the construction stage using TRIZ (theory of inventive problem solving), promote the ground painting session integrity of every ship, improve the tanks’ test plan in the dock, and reduce the time spent on dismantling operations and the painting operation. Through the TRIZ, this study proposed lots of improvements, some of which are: the watertight cabins can finish the tanks test plan completely, and the integrity of the ground painting can be promoted to reduce the range of cabin test in the dock and reduce watertight bulkheads’ dismantling time. Moreover, because of the considerate reduction of the destruction of the coating, the painting operation is of good quality. The results demonstrate that the TRIZ successfully controls the production quality during construction, reduces working time, and promotes full efficiency. This study saved more than US$1 million of the outsourcing fee.

«Руский тип» подводных лодок: от «Дельфина» до «Барса»

The rise of submarine shipbuilding in Russia of 1900–1915 was influenced by the shortage of financial, technical and personnel resources. And yet the fleet received, along with American and German, boats of domestic design. Their design was concentrated in the hands of the outstanding theorist and engineer I.G. Bubnov, who announced the development of a special "Russian type" of a submarine that embodied the theoretical installations professed by him. The ships created according to Bubnov's designs are often regarded by fleet historians as unsurpassed in the world naval technology. Such a view contradicts the concrete data accumulated in historical research and needs critical consideration. For this purpose it is used classical methods of source studies and analysis of historiographical practice. The actual data indicate the harm brought to the fleet by the monopolization of scientific and technical activities. Submariners have developed a critical attitude towards the imposed type with its inherent number of persistent shortcomings. Bubnov refused to correct the shape of the hull which caused excessive water resistance. At the same time, in an effort to achieve the set speed of the boat, the designer envisaged in his projects such a powerful power plant that it exceeded the real capabilities of mechanical engineering and was also heavy and cumbersome. The boat commanders and engineers pointed out the need to reduce the submerging time of the boats, increase their survivability, add watertight bulkheads, abandon the low-impact mine vehicles of Dzhevetsky system, make the hull shape more streamlined, but the maritime administration preferred to save time and money and dismissed claims, sacrificing the comfort and safety of the crews. The experience of the First World War and familiarization with the most successful American and British designs nevertheless prompted I.G. Bubnov in 1915-1916. to revise the design principles concerning the shape of the hull, the internal structure of boats, the nature of engines, weapons, but the more advanced projects prepared by him could not be realized.

Reconfiguring Passenger Ship Internal Environment for Damage Stability Enhancement

The traditional risk control option adopted in naval architecture to meet safety-related objectives is by regulations, targeting damage limitation, nominally instigated in the wake of maritime accidents claiming heavy loss of life. These primarily concern the introduction of watertight bulkheads, i.e., permanent (passive) reconfiguration of the internal ship environment to enhance damage stability. This has been the most common measure, manifesting itself in the wake of every serious flooding accident since the beginning, back in the 19th century. However, traditional flooding protection through watertight subdivision, to an extent dictated by IMO regulations, has a physical limit which, if exceeded, a safety plateau is reached. This is currently the case and with damage stability standards progressively increasing, the safety gap between existing and new ships is dangerously widening and with design stability margins progressively eroding, stability management is unsustainable, leading to loss of earnings at best. The need for managing the residual risk through active intervention/protection over the life-cycle of the vessel drives industry to searching and adopting a new normal. This new normal is the innovation being explained in this paper by addressing safety enchantment through a systematic reconfiguration of the ship environment for passive and active protection in flooding accidents. In this respect, the “design-optimal” internal arrangement of a vessel, is adapted and reconfigured, using passive and active containment systems for flooding incidents, in the form of high-expansion foam products. The innovation is briefly explained, claiming transformational reduction in flooding risk in the most cost-effective way available. To support wider understanding and appreciation for the latter, the paper critically reviews the whole evolution of internal ship space reconfiguration, chronologically and systematically, concluding that new technological developments and breakthroughs will bring sustainable changes to the traditional evolutionary maritime safety enhancement.

Patlama Yükleri Altında Güçlendirilmiş Çift Perde Yapısının Dinamik Analizi

Tekne yapısını bölmelere ayırmak için tasarlanan, gemilerin yaralanmaları durumunda tekne gövdesine giren suyu belli bir bölgede tutarak geminin denge durumunu korumasını sağlayan yapı elemanları bütününe su geçirmez perde adı verilir. Su geçirmez perdelerin sayısı ve yapısal dayanım özellikleri belirlenirken göz önüne alınan ana unsur geminin çatışma sonrasında su alması durumunda gemi stabilitesinin korunması ve perdenin bu su basıncını taşıyabilecek dayanım seviyesinde olmasıdır. Savaş gemilerinde ise bu perdeler, başka amaçlarla da kullanılabilmekte ve operasyonel yüklerin yanı sıra bir takım askeri yüklere maruz kalabilmektedirler. Bu çalışmada savaş gemilerinde silah isabeti sonrası kompartıman içinde patlamanın oluşturduğu blast ve parça tesiri etkilerinin azaltılmasına yönelik dizayn edilen güçlendirilmiş çift perde yapısı sadece blast yükleri altında incelenmiştir.

Parametric Formulation of the Floodable Length Curve: Application Case to Offshore Patrol Vessels

The residual buoyancy of vessels after damage has a fundamental role in their survivability and it is implemented through adequate ship internal subdivision. Traditionally the number and the position of transverse watertight bulkheads are selected for most ships early in the design phase by means of the “floodable length curve” coupled with the concept of “margin line”. However, for naval vessels, it is more and more common during the acquisition process to explore a wide domain of feasible ships, identified with the assistance of automated processes and assessed also in terms of capabilities, among which is survivability. The generation and the comparison of a considerable number of different ship configurations is very time consuming. Therefore recourse to a parametric expression of the floodable length curve is considered to be a very efficient approach and would thus enable characterisation of the ship, in terms of survivability performance. In this paper such an approach is presented, using an offshore patrol vessel (OPV) as the case study.

Study for Damage Stability Operation on Floating Offshore Wind Turbines in the Revised IEC Standard

The development of FOWTs (Floating Offshore Wind Turbines) is going into the commercial stage from the demonstration one. One of the key issues for success in the commercial stage is how to reduce the construction cost. For example, watertight bulkheads in narrow space of FOWTs become obstacles to the cost reduction from the perspective of structural complexity and manufacturing. On the other hand, new IEC TS 61400-3-2 standard describes the unnecessity of the damage stability requirement under certain conditions. To secure the sufficient safety without the damage stability requirement according to the IEC TS 61400-3-2, an examination method with a probability theory and the FEM analysis is proposed in this paper. The probability of collision with cruising ships, P1, around a FOWT is estimated to use by the AIS data, and the probability of structural total loss, P2, due to the ship collision is indicated according to the total loss curve which is delivered from the FEM collision analysis. The joint probability which is represented by the product of P1 and P2 is compared to the target damage probability, 10-4 per year. The detailed information about this method and the results of trial analyses for the FOWT off the coast of Nagasaki Prefecture are also introduced in this paper.

Multi-Objective Optimization of Internal Compartment Layout of Oil Tankers

This work deals with the design of the internal layout of a shuttle tanker formulated as a multi-objective optimization problem, balancing cargo capacity and minimizing still water bending moment with safety requirements, in particular survivability after damage. A parametric model is used to specify the internal layout of a tanker ship considering a fixed hull shape and regulatory framework. The design variables include positions of watertight members in the internal layout, such as watertight bulkhead position, double-bottom height, and wing tanks width. Merit functions are the minimization of oil outflow parameter, maximization of cargo capacity, and minimization of the longitudinal bending moment, which are, respectively, represented for reduction of environmental pollution due to damaged oil tankers, improvement of economic benefits, and safety during operation. The multi-objective genetic algorithm is used for approaching the Pareto frontiers, and the choices between the optimal designs are discussed while introducing a utility function. 1. Introduction The internal layout of the ship's hull is established in the initial stage of ship design. The size and location of the internal spaces are defined taking into consideration the type of ship and the type of content and usage of the compartments. On the other hand, survivability regulations impose limitations in the subdivision arrangement of the ship. Also, the economic competitiveness has special importance in the design of a merchant ship. Cargo capacity and building cost are some of those economic objectives that are not necessarily in accordance with the improvement of safety objectives. Thus, the design of the internal layout of the vessels can be studied as a multi-objective optimization problem targeting safety improvement after damage besides decreasing the cost functions. A diversity of internal layout designs can be investigated within an optimization framework to choose the dominating design among the feasible solutions (Nowacki 2010). However, targeting a variety of objective functions complicates the process of internal compartment design, especially when the main hull dimensions have to be kept constant (Santos & Guedes Soares 2010).

Application of Neural Network and Genetic Algorithm in Subdivision Optimization

It is complicated and time consuming to evaluate the anti-wind capability of a damaged ship. This paper tries to find a way to estimate the ship’s anti-wind capability after damage comprehensively with some simplified conditions. The index representing anti-wind capability of damaged ship comprehensively is named “Average Anti-wind Capability”. When the change of watertight bulkheads’ position is not big, with a series of data calculated by NAPA and programs developed by author, Artificial Neural Network improved by genetic algorithm is applied to study the nature of functional dependency between the“Average Anti-wind Capability” and the positions of transverse watertight bulkheads. Then, genetic algorithm is also employed to find the best combination of watertight bulkhead, making the ship have the best anti-wind capability after damage. This method is verified to be feasible and effective by example calculation.

Analysis of Corrugated Bulkhead against Transverse Plane Bulkhead in a Tanker Ship

Ship is built from thousands of integrated construction materials. The selection of a strong and efficient construction material is significant since it directly affects the weight of the ship. For a watertight bulkhead in a tanker ship, there are two kinds of bulkhead construction which are transverse plane bulkhead and corrugated bulkhead. The selection of these two bulkhead constructions for watertight bulkhead is based on the bulkhead strength analysis as well as bulkhead weight. The analysis was conducted using an engineering structural analysis software by comparing the bulkhead structural configurations which has the same von Misses tension. For corrugated bulkhead, corrugation angle was simulated between 45°- 90° while for transverse plane bulkhead, the range of stiffener distances was simulated between 400-1400 mm. The result shows that minimum corrugated bulkhead weight which is 41.18 ton can be obtained on the corrugation angle of 60o with the structural efficiency ratio of 1.79% - 30.91% while for transverse plane bulkhead, minimum weight of bulkhead which is 71.175 ton can be obtained on the stiffeners distance of 600 mm with structural efficiency ratio of 2.62% - 60.25%. It can be seen that for the same von Misses tension, corrugated bulkhead construction is more efficient in terms of bulkhead weight and cost with the difference weights of almost 30 ton.

Bulkhead Door – Critical Evacuation States

Abstract The article is a preliminary to a modification concept of the sliding watertight bulkhead door used on ships and vessels. Hydraulic or electro-hydraulic drives used to move these doors require complicated and extended pressure installations with large amounts of hydraulic fluid. Well-known operational drawbacks of these installations include high level of noise and possibility of various leaks in the hydraulic system. Being the first in a series, the present article describes and analyses critical states which can take place during evacuation of people through openings in the watertight bulkhead doors on seagoing ships and vessels.

Engaging private actors in transport planning to achieve future emission targets – upscaling the Climate and Economic Research in Organisations (CERO) process to regional perspectives

Sustainable transport analyses are traditionally carried out from two fundamentally different perspectives:a) Internal travel analysis at an organisational level, often as part of corporate environmental audits to develop internal travel policies and company travel plans.b) Macro analysis of the transport system at large, in order to assess traffic flows in relation to alternative infrastructure measures and policy actions at regional level.From a holistic global perspective, both these subsystems should share common visions and long-term targets for sustainability. This would require derivation of processes and tools by which subsystems at different scales could be interlinked and informed by global principles for sustainability. A key component of such work would be to synthesise approaches (a) and (b) in order to facilitate mutual understanding between private and public actors, and between public transport authorities governing the supply of transport services. At present there is rarely mutual understanding between these parties, which risks creating watertight bulkheads between users and providers in the transport system.This case study examined a local travel planning network in the largest business district of Sweden, Kista Science City (KSC), where (as in most larger urban business districts in the world) travel demand is likely to exceed the capacity of the transport system in the coming decade. To counteract this development, some major companies were invited to join the decision process in a joint venture with public authorities. In the project, a backcasting-orientated travel planning model was applied and refined for future monitoring of the process in a regional context. Key findings were:• Identification of motives for companies to engage in company travel planning.• Demonstration of a need for construction of tangible target scenarios pinpointing the utility and benefits of target fulfilment from both a company and an employee perspective.• The first follow-up results of Climate and Economic Research in Organisations (CERO) processes implemented in companies, which showed that emissions reduction targets were met (and even exceeded).• Construction of a regional target scenario, consistent with the company-specific target scenarios, in order to obtain constructive and target-orientated stakeholder dialogue.• Final selection of a regional action plan designed to meet the regional target scenario for KSC.

Military ship’s subdivision optimization for reinforcement of anti-wind capacity after damage

A good way of enhancing the survivability of military ships is main hull subdivision optimization design aiming to improve anti-wind capacity after damage. Begin with the watertight subdivision, this paper puts forward a method of the transverse watertight bulkhead position optimization design for improving anti-wind capacity (rated wind velocity) after damage. Taking the most serious three-compartment damage situation into consideration, transverse watertight bulkhead positions serving as design variable, the optimization model with objective function of “Average Anti-wind Capacity” after damage is established, and genetic algorithm is used to get the optimal solution. The effectiveness of the method is confirmed by a calculation example of one frigate.

Application of knowledge-based engineering for ship optimisation design

This paper presents a knowledge-based engineering (KBE) application for ship structural optimisation design. Ship structural design variables are discrete, involving a variety of design requirements and constraints; this leads to highly non-linear, multi-modal, and convergence problems in structural optimisation. Ship optimisation development has ignored the application of design specifications, expert experience and other knowledge accumulated in the design process. The best solution is to combine an advanced optimisation technique with KBE, which can capture rich information to apply in optimisation loops. During the optimisation process, there are three steps for applying the KBE technique. The first step is to select the design variable values and set the design optimisation according to the knowledge base. The second step is to select the proper design process to support the optimisation design. The final step is to check the best optimisation solutions according to the KBE techniques. This approach was applied to the example of a watertight transverse bulkhead. The optimisation design of the bulkhead shows that the optimised weight of the structure is lower than that for the design without KBE, while meeting the required constraints. The design process with KBE therefore ensures reasonable performance of this structure while achieving the minimum weight objective. In addition, it combines a structural parameterised model with mathematical optimisation, which provides a shortcut for designers with less experience in structural design. In conclusion, this proposed methodology combines knowledge from different sources and applies it to the structural optimisation design of ships, which can improve the design level and reduce designer dependence on experience.