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Suction piles have been used with great success in offshore locations in recent years due to its significant advantages over conventional piles. Wider use of suction piles is expected in the near future. A field suction pile retrieval tests was carried out inside Okpo Harbour in southern Korea in summer 2003. A steel suction pile was used to install a permanent embedded anchor in the clay seafloor soil. After the embedded anchor was installed the suction pile was retrieved using positive water pressure inside the pile. The field test provided detailed instrumentation on the relationship between the applied positive water pressure inside the pile and the resulting pile pullout. The transition of the soil strength during the suction pile retrieval process is described.

Nineth Leeds - Lyon Symp held in Leeds 7 - 9 Sept 1982 Papers are Developments in engine bearings Dynamic analysis of engine bearing systems Lubrication of small end bearings in supercharged two stroke diesel engines Theory and experiments on elastic connecting rod bearings under steady conditions Measurement of oil film thickness in diesel motor main bearings - implementation of the method and experimental results The development of bearing test systems to meet future requirements Connecting rod bearing failures in large offshore compressors Crankshaft bearings - oil film history Lubricant frothing like cavitation as well as destination of volumetric efficiency in dynamically loaded bearings Temperature variations in crankshaft bearings A review of studies of piston ring lubrication Theoretical and experimental study of ring liner friction Cylinder liner wear Honing of parent metal cylinder bores for automotive diesel engines

Ferries are making a comeback in the US because they are a cost-effective alternative for traffic weary commuters and travellers. The US gave up most of its ferries by the 1960s in favour of bridges and tunnels while most of the rest of the world continued to operate and improve on the much lower cost ferry systems. Therefore the US marine industry was not a major participant in the development of modern high-speed ferries. Now with the resurgence of ferries especially high-speed passenger ferries many US entrepreneurs are looking for proven foreign designs. Some of the design issues are discussed including the IMO High-Speed Craft Code classification and problems encountered when the British designed 318 passenger 45 knot TRICAT ferry was Americanised for construction and operation in the US.

The offshore West Africa environment is known to have long-period swells with period in excess of 20 seconds although its 100-year extreme wave height and wind speed are significantly lower than those for the Gulf of Mexico. The long-period swells present unique challenges for structural design of the Truss Spar. In particular heave motions and structural fatigue caused by the swells can be significant and must be addressed early in the design process. A comparative study between a Truss Spar and a Classic Spar on global motions is provided in this paper. In-place strength and fatigue performance is investigated using a generic Truss Spar model for both the Gulf of Mexico and West Africa environments. Motion RAOs loads structural strength and fatigue results are presented to illustrate the findings

The book emphasises the properties that make copper and copper alloys so valuable in times of energy scarcity. Also covered is the continued advancement in the methods of producing copper alloy sheet and strip. By alloying copper with other metals and by varying manufacturing processes, a great variety of properties has been available, thus increasing the usefulness of copper materials. Throughout the book, is emphasis is on selecting materials that will fulfil requirements at minimum costs. The final chapter is devoted entirely to the economics of fabricating parts from copper alloy products.

Self-polishing copolymer coatings have made a major contribution to reducing hull fouling. These coatings prevent fouling by shedding paint layers when the ship is on the move but unfortunately when the vessel is laid up this cannot occur. Underwater cleaning machines then have to be used. Some of these can be too rough removing paint and fouling. To overcome this problem a machine called Pamper has been produced by the Underwater Maintenance Company of Eastleigh. The unique features of this system include the ability of the operator to select the correct cleaning pressure for the brushes so that only fouling is removed. Also detailed in this article are the underwater painting services performed by UMC an underwater paint Hycote 151 and a surface preparation and painting system called CUPS (Colebrand Underwater Protective System).

Modern fuel injection systems of large-bore 2-stroke and 4-stroke engines are mostly actuated by a hydraulic medium which is recruited out of the main lubrication oil circuit. In order to avoid abrasive wear it is necessary to filter this side stream of lubrication oil so that it is much finer than the main stream. Traditionally filter meshes are used. However these are too coarse to obtain the best results. Finer filtration depends on the behaviour of the filter medium in interaction with the dirt accumulation and the automatic self-cleaning mechanism. The accurate definition of the efficiency of the filter medium is discussed in detail together with how it is applied in practice.

A concept is proposed to abate cohesive shoreline erosion on Sandusky Bay Ohio using wetland restoration. The USAE Research and Development Centre and the USAE District prepared the concept Buffalo to stabilise an actively eroding rail causeway along the shore of Sandusky Bay. The rail line in the study area is causing safety concerns due to structural erosion caused by coastal processes and is in danger of failure at discrete locations. Icing of rail switches during winter months when spray from breaking waves overtops the causeway also causes safety problems. The concept is described. It is concluded that the proposed Sandusky Bay wetland restoration project will serve multiple uses if designed constructed and managed properly. These uses will include: economic (protection of upland areas); environmental (habitat and water quality); and social (recreation and education) benefits.

Most of present-day scientific and archeological diving uses open-circuit compressed air SCUBA. However using air as a diving breathing gas has a number of drawbacks and these are identified. Rebreathers are introduced. These are designed to make use of a much higher proportion of the oxygen in breathing mixtures by recycling the exhaled gases through a filter which removes the carbon dioxide making the gas suitable for rebreathing. Two types of rebreather are described: a CCR (closed-circuit rebreather) and a SCR (semi-closed rebreather). The SCR is the preferred diving apparatus of almost all the world's naveys. NERC's (Natural Environment Research Council) Centre for Diving is currently evaluated the use of two types of SCR within the context of scientific diving. These are: the DSSCCD (diving set self-contained clearance diver) and the new Drager or UWATEC Atlantis 1 mixed gas rebreather. The projects will which investigate SCR use in a systematic fashion are biological and ecological in nature and concentrate on fish species which inhabit the rocky subtidal. This account summarises the practical operation of the two different types of SCR unit and discusses the potential benefits of SCR use in fish research.

Spaceborne Synthetic Aperture Radar (SAR) is able to provide sea state information on a global scale by means of the directional wave spectrum. Recent developed algorithms have been developed to obtain additional information in the spatial domain rather than the spectral domain. These methods make it possible to detect individual wave heights wave groupings in open sea areas as well as surface wind fields. This work shows the capabilities of spaceborne SAR to extract offshore information about individual waves and wave grouping for areas of about 100 x 100 square kilometres. The methods are applied to ERS-2 SAR images of the North Sea over areas close to the location of some oil platforms.

The mechanical properties of soils can never be established with complete certainty. Soils are naturally variable because of the way in which they are formed and the continuous processes of the environment that alter them. The uncertainty in the mechanical properties of offshore soils is due to the natural variability from point to point within a soil volume insufficient data and imperfect models measurement errors and other sources. The selection of soil properties for geotechnical design is often based on subjective judgement and experience and the uncertainties in soil properties are only indirectly accounted for when the characteristics design values are selected. Although statistical methods can quantify uncertainties and account for them in a rational manner they are rarely used in establishing the design soil parameters. The profession also uses imprecise definitions of 'characteristic' 'best estimate' 'upper bound' and 'lower bound' values for design. The profession needs to make a recommendation of which values to use in design. It is demonstrated here how characteristic values of soil parameters can be extracted from available data with statistical methods.

The probability distribution of the duration of events where the wave height or other metocean parameter X(t) is under or over a specified level X = u is of great importance for the planning of offshore engineering operations. The mean duration estimated by adding up the durations of the events and dividing by the number of such events is an often-used measure but it depends on the recording interval (the time interval between successive measurements). An alternative useful mean duration is proposed which weights each event by its own duration. Analysis of offshore wave data confirms the stability of this parameter to changes in recording interval.

New Zealand coastal dune systems have been invaded by Marram grass over the last 50 years. Initial work is being undertaken to model the flow over a particular coastal dune system at Mason Bay Stewart Island New Zealand with a typical marram covered foredune with a transgressive parabolic dune downwind. This paper compares Computational Fluid Dynamic (CFD) modelling of the existing topography with experimental wind measurements with emphasis on the validation of the numerical model data. After some introductory and background information the methodology is looked at. Next results are discussed.

This is the final improved version of a previously published model on the transport of nuclear contamination and other passive particles in the ocean. Two interesting advances have been developed here:(a) an SPM (suspended particulate matter) submodel including erosion transport and sedimentation; (b) a new advection-diffusion approach with numerical and computational improvements: FE (finite elements) FD (finite differences) and MC (Monte Carlo) methods have been compared and calibrated. The Baltic Sea has been chosen as the validation scenario of the model and the radioisotope Cs137 is the radiotracer to be analysed. This scenario was the most contaminated ecosystem in the Soviet Union from the Chernobyl disaster in April 1986 and the elected radiotracer Cs137 was the main long-lived radioisotope emitted to the environment. This model has a potential usefulness in other oceanic scenarios affected by a nuclear disaster in the future. It could be an interesting tool to predict and minimise the ecological and economical impacts of future accidents. The model can also be extended easily to non-nuclear contamination problems such as: oil accidents nutrients dynamics and other biological problems.

Over the last ten years there has been increased interest in developing vision systems and technologies that support the operation of unmanned submersible platforms. The potential uses of panoramic imaging for a range of vision-guided (vision-based) capabilities are considered in the deployment of unmanned submersible platforms (or space robotics systems). Two prototype imaging systems are described in forward-look and down-look configurations designed and built from six off-the-shelf security cameras. Also addressed are a number of issues for preprocessing the data to construct these views. A number of critical capabilities are studied and the potential use of the panoramic imaging system is described. Various examples to demonstrate the applications are presented. Diagrams appear on pages 6 to 8.

Techniques for the safe use of electricity in combination with current diving methods i.e. air diving mixed gas bounce diving and saturation diving are described. The electrical shock hazards for the diver are outlined and reference made to the voltage and current values needed to cause muscular paralysis or death. The practical design of underwater power supplies need to achieve conditions in which there is an inherently safe power supply; a system requiring two faults to occur before dangerous conditions arise; early warning of possible fault conditions; protective devices with anti-fibrillating characteristics and a fail safe protection system. A practical design for a diver heating system is demonstrated exhibiting these characteristics. The electrical problems of underwater welding are touched on.

Total-scattering cross-sections of Antarctic krill were measured over a broad bandwidth (36-202 kHz) using a new technique based on acoustical reverberation in a cavity. From 18 February to 9 March 2002 mean total strengths (TTS) were measured from groups of 57-1169 krill at the Cape Shirreff field station Livingston Island Antarctica and aboard RV "Yuzhmorgeologiya". A look is taken at methods covering empirical TTS of Antarctic krill and theoretical TTS of Antarctic krill. After this results are considered followed by discussion and conclusive remarks.

Sea-floor acoustic scattering strength measurements are useful for understanding the observed reverberation in active sonar systems and for estimating sea-floor bottom properties. Observed reverberation and resulting measured scattering strength frequently show a high degree of spatial and temporal variability. This variability may be observed on short sample-to-sample times scales from a single time series or it may mani9fest itself as longer term variability of measurements made at a single location of over a survey area. Causal mechanisms for this variability include a dynamic fluctuating ocean media multi-path complex bathymetry and the use of non-stationary sensors for making these measurements. He results presented in this paper leverage previous work by the SABLE (Sonar Acoustic Boundary Loss Estimation) project. Several examples of how this approach can be used to investigate variability in derived Lambert coefficients and scatter strengths are presented for a dataset constructed from sonar beam data obtained over a limited geographic area. These examples are illustrative of approaches that can potentially be developed as a means of quality control in processing large datasets from non-research sonar systems.

Invasions by non-native aquatic species are increasingly common worldwide in coastal habitats. Although the effects of many of these introduced aquatic species on habitats and communities remain largely unknown some of them have had demonstrably strong negative influences. One of the main vectors in the introduction of ANS (aquatic nuisance species) is transport in ship ballast waters. Although several ballast tank treatments to prevent transport of aquatic organisms appear promising all existing approaches will result in significant costs to the shipping industry. The implementation of BWT (ballast water treatment) measures would be hastened by providing the shipping industry with economic incentives for doing so. The authors' previous work is outlined. This suggests that deoxygenation may be such a treatment with benefit for ship owners by reducing corrosion while simultaneously limiting the number of aquatic organisms surviving transport in ballast tanks. The authors' current investigations are then described.

The effective design and use of the motion control surfaces has become an integral part of the design and operation of high-speed vessels. The proposal to implement several optimal controllers designed for different sea states is discussed and a brief description of a practical time domain model used to stimulate the motion responses of a SWATH vessel is given. A number of Linear Quadratic Regulator based optimal controllers and their use in combination with on-line switching procedure are applied to test vessel SWATH6A but were found to be sub-optimal. An Artifical Neural Network controller is proposed and has been trained to provide a similar level of control giving a non-linear generalisation resulting in a near optimal solution. The investigation's conclusions are summarized.