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The vibration performance of ships is an important design consideration. A study of the causes of these vibrations needs to include both the determination of the response characteristics and also the excitation sources due to the propeller main engine and waves. The marine propeller shafting is one of the excitation sources for axial vibrations and a major contributor to the excitation sources for torsional vibrations. It is important to be able to predict the harmonic structure of the torque and thrust during the design stage of the propeller system. Two quasi-steady methods using the lifting line theory are presented. The simplicity and accuracy of the second method is shown. This procedure takes into account a non-dimensional expression of the circulation as a two- dimensional function of the blade radius and angle of rotation. A validation calculation with experiments of propeller excitations induced into the shafting system is analysed. Acceptable agreement between calculated and measured excitations is shown.

This paper is divided into two parts. The first part looks at vapour recovery legislation and its potential impact on the independent bulk liquids storage business in Europe. This industry is reviewed and its current major concern - the framework being formulated under Annex 6 of MARPOL which will require the control of emissions of volatile organic compounds (VOC) generated when loading ships - is discussed. The second part of the paper considers the CEFIC Safety & Quality Assessment System.

Reduction of ship hull skin friction can represent significantdrag reduction for high-speed ships especially those designed for low wave drag or using catamaran-type hull designs. A method is proposed to reduce the friction by shielding the side portions of the hull from the water using ventilated cavities created with protruding wedges. These wedges create low-pressure regions in their wake that naturally ingest air at the surface reducing drag of the wedge while lengthening their trailing cavities. The proposed scheme takes advantage of the natural combination of high speeds and low pressures that exist at the waterline of a high-speed ship without requiring auxilary pumps or machinery. As a first step for engineering estimates of drag reduction preliminary experiments are presented that use the two-dimensional wedges and similarly shaped struts to validate theoretical ventilated cavity predictions. Tests are conducted on parabolic and wedge-shaped sections and struts in a closed-jet water tunnel at 20 and 30 knots using a pipe to ventilate behind the strut using natural suction.

VLFS (very large floating structure) is a unique concept of ocean structures primary because of their unprecedented length displacement cost and associated hydroelastic response. ISSC (International Ship and Offshore Structures Congress) had paid attention to the emerging novel technology and launched Special Task Committee to investigate the state of the art in the technology. The activities of the committee are summarised. A brief overview of VLFS is given first for readers new to the subject. History application and uniqueness with regard to engineering implication are presented. The MOB (Mobile Offshore Base) and Mega-Float which are typical VLFS projects that have been investigated in detail and are aimed to be realised in the near future are introduced. Uniqueness of VLFS such as differences in behaviour of VLFS from conventional ships and offshore structures are described. The engineering challenges associated with behaviour design procedure environment and the structural analysis of VLFS are introduced. A comparative study of hydroelastic analysis tools that were independently developed for MOB and Mega-Float is made in terms of accuracy of global behaviour. The effect of structural modelling on the accuracy of stress analysis is also discussed.

Volume 1 - 'Hull form data' Volume 2 - 'Resistance data' The volumes are intended primarily for naval architects who are concerned with or interested in the design of displacement-type ships in relation to their hydrodynamic resistance qualities. It is believed that the method of analysis provides a new rational division of the total resistance into two main components depending on viscosity and gravity effects which should lead to a better understanding of the influence of the hull form characteristics on resistance and hence to better design and to more accurate prediction of ship performance. Volume 1 contains straightforward presentation of the hull form data in table and figures without further comment. The whole of the compiled data has been obtained from work carried out in the Ship Division of the National Physical Laboratory over a long period of years.

Warship 2001 - 'Future Surface Warships'. Two-day international symposium. London, 20-21 June, 2001. Comprises of 8 sessions and 19 papers. Sessions as follows: classification rules and naval vessels (ABS perspective, Lloyd's Register and future surface warships), The latest generation (Swedish composite and stealth corvette, F-100 and F-310 new frigates), The future generation (Trimaran, swath corvette), Procurement and cost assessment (U.S. coast guard's deepwater program, lifetime costs of a capability), Elements of vessel design (surface naval ship, warship), Tools for analysis and design (nonlinear motion and load assessment of advanced Navy frigates, software modelling and analysis) and Closing session (use of fibre composites in naval ships, future naval gunfire support).

Proceedings of two-day international symposium 'Surface warships: the next generation' held on 11-12 June 1998, London. Contents consist of papers within five sessions: 1. DD/FF Current and future programmes (papers: F124 - Modern combat system design, Optimising manning on DD 21, Collaborative warships: Project Horizon, Re-fitter's perspective on future surface warship design), 2. Future Concepts (papers: Corvette design considerations, Catamaran escort vessel for the RNoN feasibility study, Hermes feasibility study), 3. Safety (papers on ship safety), 4. Equipment (papers: future platform management systems - cots equipment, securing and landing of helicopters onboard small ships, global maritime distress and safety system (GMDSS), 5. Ship Design (papers: computer-aided topside integration for concept design, specifying sea keeping performance in ship design process, survivability in design of future warships).

In the practice of engineering design for ships and ocean structures and in many classification rules the Morrison equation approach and the strip method are used and defined to determine motions and loads encountered by floating structure in waves. Considering the complex structure and large-scale for the semi-submersible platform the panel method is used in this computation. For the global and fatigue structural strength analysis of a semi-submersible platform the wave loads of design conditions are calculated by using the 3D boundary element method. The maximum of vertical bending moment torsion moment and horizontal spilt force are determined from a series of design waves with limited period and positions of incident wave crest. The extreme wave loads under the combination of wave parameters and the transfer functions of wave loads are used as the input of hydrodynamic pressure in the 3D FEM analysis process.

Visakhapatnam Port is the second largest major port in East India. It has all-weather port facilities. However it was reported by ships' captains that the prevailing wave conditions during the south-west monsoon at the OSTT (offshore tanker terminal) on the lee-side of the south breakwater were not suitable for handling the oil tankers causing difficulties for loading operations under moored conditions due to excessive ship motion. The Port Trust decided to investigate this. The prevailing wave conditions were examined looking at hydraulic model studies prototype investigations and desk computations in order to make suitable recommendations. The methodology and approach adopted for this problem is presented highlighting the role of hydraulic models field observation etc in identifying the root cause of the phenomena and recommending economical remedial measures.

A brief history of the United Kingdom Meteorological Office and its services to shipping begins with the introduction of the gale warning service in 1861 proceeds to the first BBC broadcast weather bulletins in 1924 and culminates with the range of present-day services and their transmission by radio broadcast radio telegraphy radio telephony and radio facsimile. The shore based routing of ships began in the USA in the early 1960s and introduced by the Bracknell Meteorological Office in 1968 is particularly considered with discussion of the main features of the service typical owners requirements for routing (least-time least damage avoidance of adverse weather) potential economic benefits and examples of contracts.

Int conf held in Norway June 2 - 6 1980 Papers are Specialised bulk carriers - their markets and future development Machinery for the future - back to coal On the design of wide shallow vessels for new sea transportation systems and tidal estuaries Design of routing systems for areas with heavy sea traffic The use of simulation techniques as a tool for vessel traffic management Analysis of vessel traffic behaviour by means of simulation techniques Comparative analysis of the profitability of a barge carrier system and a container system for a given liner trade Multi purpose cargo ships Factors influencing the engine room design in the 1980s Contribution which wind propulsion could make to sea transport systems in the 1980s Improved efficiency of ship operation by utilising communication development

This Review has sections on Marketing and human relations (e.g. the passenger cruise industry, flexible cruises for the growing family market); Operations (e.g. maintaining quality is more than a slogan, creative ship personnel training is essential, integrated software systems manage ship operations), Catering and cuisine (e.g. quality food products in St Lucia), Design (e.g. spa design to stimulate the senses, aspects of cruise ship design, design and colour in motion), Construction and engineering (e.g. sea waste disposal, low-cost screw compressors); Safety of life at sea (marine safety on board ship, marine fire protection - water mist, photoluminescent escape route systems, low location lighting), and Destinations and ports.

NIWA (the National Institute of Water and Atmospheric Research Limited) integrated a 30kHz Kongsberg Simrad EM-300 multibeam echosounder on their research ship to help meet the mapping and charting requirements of LINZ (Land Information New Zealand) and to support NIWA's science and consulting activities. Installation of the hull-mounted multibeam system was carried out and it was put through a series of stringent calibration and acceptance tests by LINZ prior to its performance of hydrographic charting in the Western Ross Sea of Antarctica. The LINZ Hydrographic Survey Standards are detailed together with their specifications for the Western Ross Sea survey NIWA's evaluation and selection of a multibeam system to meet these standards and specifications and the system's integration upon the research ship. Predicted error budgets are provided for the echosounder's vertical accuracy and feature detection capabilities. An evaluation of the calibration and acceptance testing and a comparison with the predicted performance of the multibeam echosounder are provided. Conclusions resulting from the Western Ross Sea 2001 voyage together with the mapping data collected by multibeam echosounder are presented. Experiences and issues associated with surveying in the harsh Antarctic environment during the February-March 2001 voyage are also detailed.

Ballast water exchange at sea has recently become a global matter of concern related to marine environment protection. Some countries require ships to exchange or treat ballast at sea prior to entering port. There are two methods for ballast exchange at sea: the sequential method and the flow-through method. A method is introduced to assess the fluid pressure loads in a ship's ballast tanks during ballast water exchange at sea. The 2D problem of sloshing in rectangular tanks with time varying water level is investigated using modal analysis technique which has been widely used to solve the general structural vibration problems. Since the method is based on a linear theory computational simulation of fluid motion can be performed efficiently for whole duration of ballast exchange which typically takes a few hours for each tank depending on the size of the tank and the pump capability. A focus of this study is on the possibility of a resonance of the fluid motion within a limited duration when the level of ballast water gradually changes and the natural frequency may pass through the dominant exciting frequency of ship motions in a stochastic seaway.

A turret-moored FPSO under harsh conditions is supposed to align with wind-driven waves due to its weathervane capability. However the ship can find herself beam on to the seas in mild environments as a result of a combination of wind-driven waves and swell condition. This means that a misalignment between ship's heading and waves can happen leading to large amplitudes of roll motion for a reasonably long time. This really gets worse in the case the FPSO is at low draft and the roll natural period is in the vicinity of the peak period associated with the swell condition. It is well known that one of the most effective devices to reduce the roll motion of ships is the bilge keel. The importance of the bilge keel increasing the roll damping moment stands out for resonant conditions. The results of free decay tests for various bilge keel arrangements are presented regarding roll damping coefficients. Tree representative drafts were considered for the FPSO and the bilge keel configuration varied from bare hull (no bilge keel) to bilge keel. Finally a tailor-sized bilge keel is defined for a typical F(P)SO operating at Campos Basin.

The detection of QPC (quadratic phase coupling) is an important problem in several contexts most notably in damping analysis of shock mounts design of optimal placement of machinery in plants and passive identification and classification of targets such as ships and submarines. The detection of QPC is necessary to determine if spectral lines at potentially coupled frequencies are indeed coupled. The problem of detection of QPC in a shallow underwater channel is addressed. The channel has been numerically modelled using normal mode theory. This paper addresses the problem of detection of QPC at a passive receiver when the source signal has traversed through an underwater channel. Extensive simulations have been carried out of the received signal of moving and stationary targets in shallow underwater channel to arrive at a robust algorithm for detection of QPC. The algorithm takes advantage of the slow variation of the bi-spectrum phase of the received signal which is due to the channel characteristics. Specifically the detector is based on the zero crossings of the bi-spectrum phase of the received signal across observation intervals. The proposed detector is observed to be robust in several typical shallow underwater channels. Detailed results of the detection performance of the algorithm in different SNR conditions are presented. The role of bi-spectrum in the detection of QPC is reviewed. The problem addressed is discussed. The signal model used to analyse the detector performance is presented followed by the QPC-detection algorithm. The simulation procedure is described and the simulation results are presentX45212 Detection of small man-made objects in sector scan imagery using neural networks

Laboratory-based oil analysis programs are currently the accepted method for assuring oil and machinery condition. They provide accurate results in a controlled manner often with additional expert interpretation from the lubricant supplier. The market for off-line lubricant analysis equipment is well served but coming under pressure especially from a requirement to reduce manpower or to continually monitor critical systems. A typical example would be the US Military who need a 70% reduction in manpower for the next generation of front line ships. There is a need to develop reliable and relatively low-cost on-line instrumentation capable of replicating a laboratory analysis providing information on both lubricant and machinery condition. A 3-year research programme was undertaken to investigate the practicality of a number of techniques for monitoring oil and machinery condition realised as an on-line device. Included in this were techniques of magnetometry cyclic voltammetry impedance spectroscopy (Q) capacitance or resistance and microwave. Many of the laboratory techniques used in oil analysis can be replicated in an on-board design. However an on-line realisation of the techniques used for example titration are impractical for reasons of complexity or reliability. Previous research has shown that it is possible to develop on-line instrumentation that does replicate laboratory techniques but these types of systems again have cost and complexity considerations that severely limit theiX44478

A ship represents one of our most complex and sophisticated man/machine systems. Just with the growth of automation aboard shops, the task of the man is concentrated more and more upon controlling functions. Consequently, a ship designer is increasingly confronted with ergonomic problems where the man-machine relationship involves the operator as a controller. Knowledge must be gained about the way in which they affect one another both in a favourable and unfavourable sense. It is important to consider the human perceptual and control capabilities when designing a particular system. If one analyses what man has to perform when he is accomplishing his task, let's say, on the bridge, it appears that we are dealing with a cycle: man perceived information about his environment processes the information and decides on the basis of this information what to do and finally acts. The ergonomic problems dealing with this cycle is discussed under the main headings: perception, decision making and handling.

LNG FPSO is one of the hot issues in offshore floating body dynamics. It requires accurate analysis of hydrodynamic interactions between two vessels: LNG FPSO and shuttle tanker. In many cases where FPSO and shuttle-tanker have been conventionally tandem-moored hydrodynamic interaction between FPSO and shuttle tanker has been ignored since it was assumed that the interactions were not so large as to need to be accounted for. Such assumption implicitly presumed that ignorance of the hydrodynamic interaction gave conservative estimates of the behavior of both ships: FPSO and shuttle tanker. Here basic interaction characteristics of tandem moored vessels and side-by-side moored vessels are experimentally investigated. Model tests are carried out for tandem-moored tankers and side-by-side moored tankers in regular waves. Motion responses and drift forces of two vessels are measured and the change of drift forces is mainly investigated. Interaction characteristics are also investigated for change of distances between two vessels as well as types of mooring pattern; tandem and side-by-side moorings. All the cases of two-body interactions are compared with calculations using a higher-order boundary element method based on generalized multi-body interaction theory. Results are presented and discussed and conclusions drawn.

The longitudinal connections at the inner and outer hulls of ocean-going vessels often experience fatigue cracking as a result of dynamic stress fluctuations due to environmental loadings. A crack may begin at the area of stress concentration. It can then continue to grow through the longitudinal stiffener until it reaches the shell plate. Subsequently it creates a surface crack that goes through the plate. If this crack is not repaired it can grow to a critical size and may result in catastrophic structural failure. As a result it may induce structure failure and associated significant environmental impact and large financial losses. In view of previous studies on the fatigue analysis of ships and offshore structures shell elements are commonly used to calculate hot spot stress for complex connections. There are few studies using solid elements for longitudinal connections. Shell elements simulate only the mid-plane of a plate and weld is not modelled or modelled by some idealisations such as rigid links inclined shell element etc. This paper deals with a rigorous fatigue analysis using solid elements with full weld representation. A full-scale test of side longitudinal in FPSOs tested by DNV (Det Norske Veritas) is introduced and FE comparative studies are presented. After this effects of weld returns to connect two fillet welds and non-welded gaps in fillet weld are discussed. Finally