Search our collections

The prediction of non-linear motions and hull girder loads of an FPSO operating in extreme seas is of critical importance for the assessment of structural integrity of the vessel. Although the non-linear effects due to large-amplitude ship motions and the associated hydrodynamic loads are generally recognised the effect of different non-linearities on the prediction of hull girder loads and responses has to be identified through systematic studies. FPSO hull girder loads are commonly calculated using ship classification rules or predictions based on linear 2D or 3D hydrodynamic theory with additional factors to account for non-linearity. The level of inherent uncertainty in these prediction techniques has to be identified through case studies. Here the effect of non-linear load predictions on the ultimate hull strength assessment of an FPSO is investigated.

Formerly 'Muckle's Naval Architecture for Marine Designers' The fundamental characteristics of a ship's design and how they affect its behaviour at sea are of great importance to a variety of different people, including naval architects and marine engineers. The book gives a clear and concise introduction to the subject. Chapters comprise of: Definition and regulation (hull form, displacement, freeboard and load lines, IMO and classification societies), Ship form calculations (rules), Flotation and stability (equilibrium, transverse metacentre, longitudinal stability, statical stability, dynamical stability), The environment (water, wind, waves, extremes, marine pollution), Seakeeping (ship motions, stabilisation), Strength (stresses, forces on a ship, fatigue, superstructures, structural elements, transverse strength, finite element analysis, structural safety), Resistance (fluid flow, the Froude notation, wave-making resistance, frictional resistance, roughness, model and full-scale tests), Propulsion (the screw propeller, torque, ship trails, main machinery power), Manoeuvring (turning circle, zig-zag, spiral, rudder, submarines), Vibration, noise and shock (damping, disturbing forces, beam flexing), Ship design (design features, efficiency, safety, design process, merchant ships, bulk cargo carriers, passenger ships, tugs, high-speed craft, warships, submarines).

Lightweight high-speed craft are not passenger ships in the conventional sense and the Code of Safety for Dynamically Supported Craft (DSC code) resulted to enable administrations to approve of these novel craft. IMO encouraged governments to adopt the code but neither the UK nor Hong Kong has done so. This paper studies the legal problems associated with the application of conventional passenger ship regulations to high-speed craft and the reasons why many countries have been reluctant to legislate for the code. It speculates on the likely response to the revised code for high-speed craft and gives opinions on the legal and insurance implications of not keeping the rules of novel craft abreast of their designers.

There are situations where a marine structure is subjected to stress cycles of such large magnitude that small but significant parts of the structural component in question experience cyclic plasticity. Welded joints are particularly vulnerable because of high local stress concentrations. Fatigue caused by oscillating strain in the plastic range is called 'low cycle fatigue'. Cycles to failure are typically below 104. Traditional welded joint S-N curves do not describe the fatigue strength in the low cycle region (< 104 number of cycles). Typical Class Society Rules do not directly address the low cycle fatigue problem. A literature review of material behaviour and strength of marine steels is first presented. Characteristic parameter values of cyclic stress-strain curve and strain-life curve are established based on the literature study experimental testing and non-linear FEA. An S-N curve is then proposed in order to define the fatigue strength in the low-cycle regime. Finally a fatigue damage calculation method is developed based on a hot spot stress approach.

As easily accessible energy resources diminish the search for oil and gas is shifting to more technically challenging areas. The most prominent amongst these new areas are deeper waters of the ocean and ice-covered areas. There is now serious interest in the High Arctic and other areas offshore with even more severe climates. Several drilling projects have been proposed and despite the general reduction of ice cover in the Arctic designers face many challenges in designing offshore structures that strike the right balance between safety and economy. For example the climatic data that designers require are sparse and uncertain. This paper presents a Classification Society perspective on the challenges faced by both designers and operators of offshore installations in the Arctic. The work ABS is undertaking often in cooperation with others in the industry in developing technology tools rules and guides is described. Also discussed how risk methods can assist in the task of assessing structures that are novel

Symp held in Italy 14 - 18 Nov 1960 Papers are Economic analysis of nuclear shipping Marine nuclear propulsion - economics in perspective Some aspects of the propulsion economics in maritime and continental transport in Yugoslavia ENEA survey of nuclear ship propulsion activities in Western Europe Survey of Japanese activities in nuclear propulsion New regulations and recommendations applicable to nuclear powered merchant ships Testing experience with the NS Savannah Some safety considerations of nuclear propulsion plants in ships Safety of nuclear ships Classification standards for nuclear powered ships Evaluation of rules and regulations for nuclear ships Port entry control and safety assessment provisions of the 1960 SOLAS Convention as applied to the NS Savannah Some safety problems in the Fiat Ansaldo nuclear ship study Method of safety analysis of a steam cooled marine reactor Safety aspects of the marine advanced gas cooled reactor Nuclear safety considerations affecting the design of the maritime gas cooled reactor

The need to consider the system as a whole in order to achieve successful system integration is discussed. Process modelling is the creation of a virtual prototype; an electronic model of the design based on the physical properties of the system and a set of rules to govern loads moving through the system. The models can incorporate equipment and operator availability as well as modelling complex mechanisms. The virtual prototype can be used via an electronic link to test the control system. The key design driver for optimising onboard logistics has been the desire to reduce manning levels. It is shown by way of a CVF example how automation and modern simulation tools are used to produce a concept design solution.

Following the introduction of podded propulsors into the marine industry the market demanded a rapid increase in size of the units from a few megawatts to in excess of 20MW. Such an increase led Lloyd's Register to undertake a major research programme into the loadings experienced by these propulsors and the way in which they are reacted by the individual components. In addition much emphasis was given to the practical problems of achieving the design intent both at the time of building and subsequently through life. The results of this work were used to update the Rules and in developing a system of survey procedures which embraced the practical problems of initial manufacture and assembly as well as dry-docking maintenance activities. This paper summarises much of this work.

World wide there is increasing interest in using ships of opportunity (SOOs) to acquire oceanographic data. New technologies mean that data for a wide range of parameters can be reliably measured and the data sent ashore in real time for analysis and assimilation into models. Commercial ships running regular routes provide data well suited to the validation of models. As they run year round they provide unaliased obersvations of seasonal changes. The scale of the operation can vary from global transporters to short ferry crossings. The EU ferryBox project has established "ground rules" for the development of new ventures. These will help to assure data quality and assist data management. The EU project CarboOcean and operations sponsored by the IOC are establishing global coverage for measurements using SOOs. The route operated by NOC between Portsmouth and Bilbao since April 2002 has already provided valuable information on water flow from the Bay of Biscay into the English Channel a new method for assessing plankton production and clear evidence for inter-annual variation in the supply of nutrients fuelling plankton production.

The committee gives an overview about new developments in the field of ship and offshore materials and fabrication techniques with focus on trends which are highly relevant for practical applications in the industry in recent and coming years. Particular emphasis is given to the impact of welding and corrosion protection techniques on structural performance on the development of lighter structures and on computer and IT technologies and tools which are meant to link design and production tools and to support efficient production. Chapter 1 acts as an introduction. Chapter 2 reviews general situations of the research works. Chapter 3 investigates the impact of welding towards the structural performance. Chapter 4 describes latest development of new materials and lightweighting in shipbuilding. Chapter 5 focuses on effective means to cope with the stricter corrosion protection rules in terms of materials coating systems and application. Chapter 6 summarizes recent developments in computer applications in terms of cost estimation accuracy management and simulation based design. Chapter 7 gives conclusions and recommendations.

A test program on short thin-walled I-sections in combined compression and major axis bending is presented. The experimental program aims to determine the section capacity for two different I-sections when subjected to compression and major axis bending. The program includes pure compression and pure bending tests as well as tests with varying ratios of axial-force to end moment for each cross-section. Firstly a look is taken at the test specimens followed by the test rig. Next the test results are given. Lastly design rules are considered.

The process of ship construction has undergone rapid changes throughout the latter half of the twentieth century. The decline of the traditional slipway building berths and the introduction of dedicated newbuilding dry docks in purposely redeveloped or completely new shipyards has revolutionised the shipbuilding industry. This paper provides a general overview of some current shipyard practices and ways in which the attending Surveyor can ensure compliance with the applicable Rules and Regulations. The introduction of ShipRight procedures specifically that of Construction Monitoring and its impact on the work practices of the Surveyor are also discussed.

The construction of replica or near replica versions of traditional sailing craft has become quite popular in the seacoast areas of the USA as private groups and local state and federal governments realise the historical importance of their maritime heritage. Formerly these vessels were generally used as static floating exhibits. Now increasingly the vessel's sponsors require that first the craft's appearance and function be traditional and second that it must be capable of being certified by the USCG (Coast Guard) for either the carriage of passengers or for some form of sail training. There are quite a few significant although not insurmountable challenges involved in reconciling the appearance and functionality aspects of a vessel with the various regulatory requirements imposed. One area is focused upon here - the design of the vessel's rig. The GL (Germanischer Lloyd) rules are considered. While it is a relatively simple structural calculation to assign loads and their location and direction to an individual part of a rig

In the frame of the harmonization of the European design rules in the Eurocodes a new approach the Annex C of Eurocode 3 Part 2 has been developed. The Annex C concept for Eurocode 3 Part 2 is a fracture mechanic based concept for the choice of steel material to avoid brittle fracture. First some background information is given. Next the safety concept of the Eurocodes is considered. After this a look is taken at Annex C of Eurocode 3 Part 2. Lastly tables for the choice of steel material are explained.

Full scale measurements of cargo acceleration were carried out on three specially instrumented Dock Express Heavy lift ships during two years commercial trading on Japan-Middle East routes in many sea conditions. Extensive long and short term statistical analysis of the results are compared with predictions made by commonly used theoretical design methods (including `rules of thumb' DnV RP 2-design diagrams response calculation from model tests and the LONGEX wavescatter programme). A design method based on measure acceleration climate of a given trade ro route is proposed.

Safety assessment based on conventional methods such as probability risk assessment (PRA) may not be well suited for dealing with innovative systems having a high level of uncertainty particularly in the feasibility and concept design stages of a maritime engineering system. By contrast safety models using fuzzy logic approaches employing fuzzy IF-THEN rules can model the qualitative aspects of human knowledge and reasoning processes without employing precise quantitative analyses. Fuzzy-logic-based approaches may be more appropriately used to carry out risk analysis in the initial design stages of large maritime engineering systems. This provides a tool for working directly with the linguistic terms commonly used in carrying out safety assessment. This paper focuses on the development and representation of linguistic variables to model risk levels subjectively.

Modern shipping activities are carried out via a highly sophisticated man-machine system within which technological, social and environmental factors often contribute to the occurrence of human failures. Due to the high risks caused by such failures, human reliability analysis (HRA) has always been a serious concern in marine engineering safety. However, the problem of lack of data, together with the complexity of marine engineers' behaviour, has weakened the applicability of well-established HRA methods (i.e. cognitive reliability and error analysis method (CREAM)) in the maritime context. This paper proposes a modified CREAM to facilitate human reliability quantification in marine engineering by incorporating fuzzy evidential reasoning and Bayesian inference logic. The core of the new method is to use evidential reasoning to establish fuzzy IF-THEN rule bases with belief structures, and to employ a Bayesian inference mechanism to aggregate all the rules associated with a marine engineer's task for estimating its failure probability. Consequently, the outcomes of this work can also provide safety engineers with a transparent tool to realise the instant estimation of human reliability performance for a specific scenario/task.

Intact stability requirements for the design and operation of offshore supply vessels are subject to international codes and regulations as well as national and regional safety agencies. However currently the design of this type of vessels is largely re-evaluated due to the expansion in size as well as the novel developments in engine propulsion and control systems. A review of current codes on intact stability is presented together with their comparison against each other in terms of important design and operational parameters. This is followed by the presentation of the new developments in intact stability using probabilistic and deterministic methodologies to address the physics of the problem and to encompass the dynamic behaviour observed in the actual operation of offshore supply vessels in a way that the ensuing instrument is amenable to designers operators and regulators aspects which are usually neglected or covered too broadly in the many codes currently available. This includes the new developments in propulsion and control systems and their possible effects on the intact stability requirements. Finally conclusions are drawn about the applicability of the current intact stability rules and recommendations are made on their suitability for safe operation of new and future generations of offshore supply vessels.

No other areas of shipping are so affected by rules regulations and trade requirements for high quality as the bulk chemical and petroleum sectors. The degree of regulation and limitation has increased significantly over the years. There is also bound to be further regulation in the future. Access to a large amount of information is needed to ensure compliance with regulatory and trade requirements and the immediate availability of emergency requirements in the event of a casualty. The problem is exactly how does the shipowner or operator or master handle all of this information in a timely manner? Ship operators need a tool that makes it easier for them to meet the demand for sage cargo operations. With the development of high capacity personal computers during recent years a tailor-made computerised information system is a logical solution to this problem. Such a system should contain all the relevant information required in one place. The time has come to emphasise the provision of tools to assist the shipboard staff in the task of ensuring correct safe and quality handling and transportation of the cargo. The concept of an effective computer-based information system capable of storing and processing the large amount of data necessary to operate in today's regulatory environment is presented.

As modern container carriers become larger certain parts of the existing prescriptive rules may pose increased uncertainty due to a lack of service experience. A comprehensive full-scale measurement system was developed to measure the wave environment ship motions and structural loads. The complete system was developed to measure the wave environment ship motions and structural loads. The complete system consists of the hull stress monitoring system onboard wave monitoring system and voyage optimization system. The hull stress monitoring system employs ten long base strain gauges to measure the hull girder bending moments and torsional moment. the onboard wave monitoring system which is based on the X-band radar signal is used to monitor and display the significant wave height periods and direction. Data from the vessel operation and navigation are obtained from the onboard voyage optimization system. the system was installed on an 8063 TEU container carrier in 2006 and the measurement campaign is currently underway. This paper presents the design of the onboard measurement system installation anf testing of the system. A description of the methodology to derive the torsional moment from the strain gauge signals is also included.