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The trimaran design has generated intense interest in recent years. There has been a combination of design studies numerical simulation model testing and the construction of the large ocean-going technology demonstrator RV Triton. It is now becoming a viable option for both military and commercial applications. Lloyds Register is now developing Trimaran Rules (Rules for Classification of Trimaran Ships). These rules include development of design loads applicable to the unique hull form of a trimaran as well as a direct calculation procedure for analysis of new trimaran designs. The structure and content of the Trimaran Rules are briefly described together with the rule development process involved. Some of the assumptions made are highlighted. The emphasis is on the development of primary loads which are the main dimensional loads and the data used for calibrations.

The effect of the propeller's surface condition is often overlooked when examining the reduction in ship performance associated with the condition of the ship's hull. Nevertheless the result can be significant. While the most common cause of propeller deterioration is corrosion fouling is significant. A study into the possible benefits of the use of foul release systems on propellers is presented. These benefits include increased propulsive efficiency and fuel savings lower maintenance costs and a cleaner environment. A literature review was carried out looking at the effect of propeller surface conditions on ship performance and at propeller coatings for merchant ships. Next theoretical calculations on the possible gains are explored for a merchant ship propeller type using a propeller lifting surface analysis programme. These showed that the significant losses in efficiency caused by blade roughening can be avoided by cleaning and polishing the blades or by the application of a foul release coating with a surface finish equivalent to a new or well-polished propeller. Research is ongoing and the calculations had still to be validated with model tests.

IMO Marpol 73-78 Annex 6 (Regulations for the prevention of air pollution from ships) came into force in May 1997. Following this the fuel additive Econofree A was developed to reduce the density of the smoke contained in the exhaust gas of diesel engines. In order to verify the effect of the fuel additive 73.6 kW diesel engine tests were carried out. The experiment was performed with MDO treated by the fuel additive at 30% and 75% engine load. The dust density the gas components etc. were measured and results obtained. It is shown that by increasing the dosing ratio: (1) dust density and smoke density increase; (2) the rates of fuel oil consumption decrease; (3) CO emissions decrease while NOx emissions increase a little. These changes are more noticeable when the amount of air intake is small.

Development by the Canadian Forces of a machinery health monitoring programme in ships and aircraft is described based upon the portable octave wave band analyzer. The relation between velocity and vibration severity in a machine is shown and the diagnostic capability of the analyzer is pointed out. Vibration readings are repeatable at normal operating conditions. Vibration readings must be taken close to each principal bearing of a machine. Machinery deterioration can be monitored by taking periodic measurements of vibration levels. Norms for the vibration levels of the various machines in the programme were established to improve diagnostic capability. A computerized vibration adata analysis system using VIBANAL and VIBLIST programs is in use in the Canadian Forces. The Dockyard Pre and Post Refit Vibration surveys and the Shipboard Periodic Machinery Health Vibration surveys are described. Acceptance analysis of overhauled machinery has been introduced. Helicopter Engine Alignment Check Procedures are described. A study of the cost-effectiveness of the VA programme has shown that unscheduled maintenance and operational breakdown have been reduced by 45% with a reduction of repair costs and improved ship availability.

Perfection of ships of the last generation in fleets worldwide is directly connected with development and introduction of the ship electronics which include not only the operating speed but also the sophisticated information integrated and intellectual systems. After some introductory information and questions a look is taken at the main stages of the warship electronics development in the largest naval powers covering submarine automation and automation of surface combatants. Next an outline of warship electronics development is provided. Lastly accompanying problems are considered.

The MAN B&W electronically controlled two-stroke diesel engines have now been in service for nearly 20000 hours with excellent results. A large number of engines are currently being produced encompassing all cylinder diameters ranging from the S50ME-C to the world's largest the 12K98ME with an output of up to 93000 bhp while the K108ME awaits the upsizing of ships. The experience collected during development production and operation in service is outlined and the impact of the updating process on the mechanical design on computer hardware and on the engine control and monitoring software is described. The results of MAN B&W evaluations are discussed and the potential

The commercial communications needs of the marine industry are highlighted and the usefulness of a global network for commercial purposes is examined. A global network provides the means of accessing the network by single code dialling. This can result in more efficient use of the system and the resulting cost benefits. The aim of this paper is to explain the complexities of satellite communications and identify opportunities which arise through the development of digital techniques and deregulation. It should be remembered that some 65 countries have invested in INMARSAT to improve communications with ships at sea which helps to increase efficiency and lower operating costs.

The use of existing LNG vessels in projects rather than newbuildings can lead to savings of around $20 million per vessel per year. However existing vessels need to demonstrate their ability to meet the challenge of further long term employment in the same way as newbuildings. Existing vessel availability is outlined and the benefits of using existing vessels are described. The three kinds of opportunities arising for existing ships are extension projects expansion projects and new projects. To benefit from these opportunities the existing vessels must provide equivalent performance as far as possible to newbuildings. Vessel maintenance/operation spare transportation capacity the reality of downtime risk and increasing acceptance of the use of existing vessels are considered.

Modern highly charged diesel engines are widely used for the propulsion of naval ships because of the good combination of performance and economy they provide. The behaviour of the engine is dominated by the complex interaction between the reciprocating core engine and the exhaust gas driven gas turbine that provides the necessary air. The matching of the turbine(s) and compressor(s) with the engine determines the performance especially in part load and transient conditions. A systematic evaluation of turbocharger matching parameters is presented against the background of a realistic ship propulsion load profile. The result shows the potential and the limitation of the turbocharged diesel engine and how different control strategies can be used to accommodate different challenges.

The 100 years progress and development in the science of naval architecture and art of shipbuilding since 1860 are well brought out in the twelve chapters of this book. The contents cover the following topics: iron ships; turrets or casemates; freeboard controversies, Froude’s model experiments; Introduction of steel; naval and merchant ship development; battle of the boilers; triumph of the steam turbine; the test of war; swords into Ploughshares; Shipbuilding’s slow revival; war and post-war years once again; rapid technical advance.

Welfare facilities are sometimes still seen by some as something generous and philanthropic rather than as a necessary condition for maintaining a healthy efficient and safe crew. ILO convention 163 and recommendation 173 were adopted in 1987 as a response to the needs of welfare facilities on board vessels and in port. All those countries that ratified it assume responsibility for taking care of the welfare of any seafarers on board any vessel in their ports on board their own national ships. The development of this convention and recommendation are described in regard to the International Committee on Seafarers' Welfare created as an international umbrella organisation dedicated to the practical implementation of the International Labour Organisation instruments on Seafarers' Welfare.

Conf held in London Nov 3 - 5 1981 Papers are Microprocessor - mainframe relationships in the analysis of offshore structures The benefits of a computerised weight control system Precise positioning of offshore structures Computer aided equipment removal route studies Training by simulation - safety and economics The simulation of an offshore field production system to evaluate its response to contingencies A computer aided operations installations for oil production in the Niger Delta Microprocessors in flow measurement applications A turnkey project management system based on a mini computer for the management of offshore projects Manoeuvring control systems for support vessels and supply ships The requirement for a high technology "Personnel on Board" system A computer based machinery monitoring system for the utilities shaft on the mobil Beryl "A" production platform Acoustic emission systems for offshore structural monitoring On line integrated maintenance management systems The use of mini computers to support offshore maintenance operations Maintenance and inspection documentation management automated retrieval display and comparison systems Acoustic communication systems for untethered vehicles - design requirements and state of the art survey

Three articles from the Life-extended Ship feature series. Hull Renovation concerns Lloyd's Register Condition Assessment Scheme which considers how vessels of older tonnage could be enhanced to a level comparable with ships of a lesser age and details of the renovation of the Hellespont Paradise are given. Extending the Life of LPG Carriers examines the assessment and renovation of LPG carriers which suffer from high corrosion rates and increasingly stringent safety regulations. Noell-LGA have developed a renovation project which covers the ballast and heeling tanks ballast piping shell plating the propeller sea chests plugs anodes and safety equipment. Breathing New Life into Tired Engines concerns turbocharger retrofits for older engines to reduce fuel consumption thermal loading servicing problems and wear and erosion. Details of recent turbocharger retrofits are given.

Although it now dates back more than a decade the MC engine programme has remained highly competitive thanks to constant updatings of the individual types as well as the addition of new models to the programme. Unit powers range from modest 1500 hp from the 4S26MC to 93160 hp from the latest 12K98MC-C for container ships. Due to the inherent simplicity and operational safety of these engines they are above all used for single engine installations coupled directly to the propeller or generator. Installation aspects such as optimisation of firing order integrated electronic controls cylinder pressure measuring systems load limiter systems exhaust valve system cylinder lubrication and turbocharging control system are discussed. Emission control levels proposed by IMO can be met using the primary methods of NOx control.

Floating systems such as ships barges or semi-submersibles show a dynamical behaviour which is determined by their internal structure and the operating conditions caused by external forces e.g. due to waves and wind. Due to the complexity of the system which commonly includes coupling of multiple components or non-linear restoring forces the response can exhibit inherently non-linear characteristics. Here different models of floating systems are considered. For the ideal case of purely harmonic forcing they all show non-linear behaviour such as sub-harmonic motion or different steady state responses at constant operating conditions. The introduction of random disturbances leads to deviations from the ideal case which may change the overall response significantly. Advantages and limitations of the different mathematical models and the applied numerical techniques are discussed.

The skills of the naval architect tend to be neglected by ship owners and operators who traditionally select engineering and operations managers from the ranks of ships' masters and chief engineers. Naval architects are however degree-qualified engineers capable of holding management positions throughout the maritime industry. In particular naval architects can help owners to interface with shipbuilders ship repairers classification societies and consultants in many areas. This will improve the exchange of information both internally and externally. A systems engineer uses engineering economic models linear programming decision analysis and numerical methods to address project planning engineering design and management issues. Examples that illustrate the way in which the naval architect can contribute expertise as a systems engineer are provided.

An expert in shipping finance discusses the concerns of financiers regarding the introduction of new legislation (the New Rules) subsequent to the 1995 SOLAS Conference: particular consideration is given to the probable effects of the New Rules on the financing and operating of ships and on the various relationships between financier and operator (lender/borrower lessor/lessee commercial charter): specific problems of transactions which involve the assessment of vessel value ship earning potential lessor liability and commercial charter arrangements are examined: issues arising out of the imposition of the New Rules which might lead to litigation or which might affect insurance are also briefly considered.

Eighth Cong held in Washington 12 - 17 Sept 1983 Papers are The accredited curriculum in marine engineering systems at the US Merchant Marine Academy The developing role of the learned society Engineering education in the area of naval construction in developing countries - the experience of Chile A portable device for crankpin and shaft rectifying in place without shaft dismantling Improved performance of compact diesel engines and its implication regarding naval ships Propulsion systems and ship operating efficiency - Optimism of the marine transportation cost thanks to medium speed engines Aspects of the design and installation of a load/unloading crude oil system with a single point mooring buoy Numerical simulation of the low frequency motions on the horizontal plane and tensions on the mooring lines of an offshore moored vessel

Articles include: Precise identification of hull interactions (features of GL's Integrated Fatigue Analysis developed as part of the Future Dimensioning and Design of Hull Structures project discussed together with factors contributing to dynamic loading in seaway): Prescriptive rules failure generates new response to hull design (General principles of the ABS SafeHull system for tankers and bulkers developed to take account of design with material capabilities and due to replace the existing rules in 1995/96): Environmental conditions must be considered (DNVC guidelines for fatigue assessment of ship structures with the effects of structural design fabrication loading and environment discussed): Sophisticated structural fatigue assessment (procedures of LR's ShipRight programme applied according to ship type include Structural Design Assessment Ship Event Analysis and for large and innovative ships Fatigue Design Assessment): Real-time hull stress corrosion and crack monitoring (basic concepts installation interpretation and applications of Strainstall Engineering's StressAlert and BMT SeaTech's SMART hull stress monitoring systems).

This is a code of practice for the construction, machinery, equipment, stability, operation and examination of sailing vessels, of up to 24 metres load line length, in commercial use and which do not carry cargo or more than 12 passengers. Chapters cover application and interpretation, construction and structural strength, weathertight integrity, water freeing arrangements, machinery, electrical arrangements, steering gear, bilge pumping, intact stability, freeboard and freeboard marking, life-saving appliances, fire safety, fire appliances, radio equipment, navigation lights, shapes and sound signals, navigational equipment, miscellaneous equipment, anchors and cables, accommodation, protection of personnel, medical stores, tenders (dinghies), storm sails, manning, compliance, vessels operating under race rules and clean seas.