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The use of gyro-dynamic forces to counteract the wave-induced roll motion of marine vessels in a seaway was proposed over 100 years ago. These early systems showed a remarkable performance reporting roll reductions of up to 95 percent in some sailing conditions. Despite this success further developments were not pursued since the systems were unable to provide acceptable performance over an extended envelope of sailing and environmental conditions and the invention of fin roll stabilisers provided a satisfactory alternative. This has been attributed to simplistic controls heavy drive systems and large structural mass required to withstand the loads given the low strength materials available at the time. Today advances in material strength bearings motor technology and mechanical design methods together with powerful signal processing algorithms has resulted in a revitalised interest in gyro-stabilisers for ships. Advanced control systems have enabled optimisation of restoring torques across a range of wave environments and sailing conditions through adaptive control system design. All of these improvements have resulted in increased spinning speed lower mass and dramatically increased stabilising performance. This paper provides an overview of recent developments in the design and control of gyro-stabilisers of ship roll motion.

AFCON (Advanced Frigate Consortium) a trans-Atlantic shipbuilding team combines the expertise of IZAR Bath Iron Works (BIW) and Lockheed Martin. AFCON is committed to providing international customers with affordable Aegis Surface Combatant Solutions using state-of-the art technology and designs. One of the new products developed on the basis of the huge experience of the three companies is the AFCON Corvette the smallest of the AFCON combatant ships family. The AFCON Corvette is an affordable high performance surface combatant solution tailored to meet the needs of navies operating around the world and represents a cutting edge technology design which integrates the very powerful and well-proven Aegis AAW system in the minimum sized platform. The aim of this paper is to reflect the design drivers main characteristics and ship capabilities that make the AFCON Corvette the best vessel of her class.

The author has since 1998 been actively involved in R&D on various Air Assisted Vessel solutions with the overall goal to supply fast vessel technology with capabilities and performance beyond existing State of the Art (SOA) conventional solutions. The research has been hihgly market driven where different applications and segments have been addressed individually to meet end users requirements and operational missions. Solutions have been developed for naval paramilitary commercial and pleasure boat end-users. The market leading hull forms today are generally quite conventional and do not differ much from the corresponding hull forms used some 20 years ago. The fast vessel industry generally agrees that quite radical design changes will be required to develop the "next generation of fast vessels and ships".

Natural gas and vegetable oils have long been established as alternative energy sources suitable for road transport vehicles and power generation using conventional engines. However the use of these fuels for commerically-operated high speed marine craft in inland waterways and harbours is not common. In this investigation the performance and emission levels in the operation of a single-cylinder spark-ignition engine using natural gas are compared with data for diesel gasoline and emulsified vegetable oil under simulated propeller-load and near lean-misfire limit conditions for high speed craft. The brake specific fuel consumption with natural gas operation was found to be higher when compared with those of diesel and emulsified vegetable oil. The NOx exhaust emissions from operation with these fuels were found to be lower than the limit set in Annex VI of International Maritime Organization (IMO) MARPOL 73/78: Regulations for prevention of air pollution from ships

A 3-D method based on Rankine Sources for computing responses of ships in waves is presented. The theory used is briefly outlined together with the numerical method. To prove the adequacy of the methodology in the high-speed range some applications are presented and compared with experiments. These applications are a high-speed round bilge frigate hull in head waves a catamaran at two different separations in head and oblique waves and a trimaran hull in head waves. Finally a comparative computation of three typologies (a mono-hull a catamaran and a trimaran having the same displacement and speed) is presented.

For welded structures such as ships and rolling stock a technique of precise evaluation of the fatigue strength of the welded joints is a critical factor for assuring product quality. The present general method for fatigue strength evaluation depends primarily on the classification of the joints and the corresponding allowable stresses. The fatigue strength evaluation method of welded joints using HSS (hot spot stress) has been suggested to improve the reliability of structures. It is not easy to calculate HSS and the stress intensity factor that is needed to evaluate fracture from the root gap by means of FEA. The basic theory and examples of the application are described.

Bigger and bigger ships and other sea structures are being built. Therefore the stress on certain areas such as the welding region is increasing. Crack growth is investigated by applying a fatigue design technique using new FE analysis algorithms which consider compressive residual stress redistribution near the crack tip. The size of the plastic zone near the crack tip was obtained by elasto-plastic analysis and it was compared with Irwin's equation. The amount of residual stress redistribution was assessed by subsequent elasto-plastic analysis and the difference of residual stress distributions under constant amplitude load and overload was obtained. To analyse the fatigue crack propagation the applied SIF range was evaluated by ASTM E647 and the effect of residual stresses on crack propagation was considered using the effective SIF concept. The test results of crack propagations were compared with the predicted data obtained by the analysis.

Many factors need to be taken into account when designing a ship for cold climates and icy waters. National authorities typically set ice class requirements so that in meeting then ships have sufficient capacity to operate in the intended conditions. A variety of ice class rules can be considered depending on the operating area. In addition to the main dimensioning criteria for azimuth thrusters each manufacturer applies its own product-specific rules. The first tugboats with ice class were fitted with azimuth thrusters in the early 1970s. Gradually the use of azimuth thrusters as the main propulsion for tugboats grew more popular and many tugs were dimensioned and also surveyed for ice class. During 2005 a total of 90 tugboats were commissioned equipped with our Ulstein Aquamaster azimuth thrusters and one third of these were so-called ice-classed units. Azimuth thrusters in ice-going tugs are examined and discussed.

This book traces the continuing development of one of the most important specialised subsidiaries of the tanker sector. It is itself a multiplicity of sub-specialisation from the large and sophisticated liquid liners of the parcel trades, down to small vessels distributing a restricted number of products on short sea routes. The book has been divided into six separate parts. The first, central to any understanding of both the markets and the ships that serve them considers the broad groups of chemicals that are carried by sea, their origins and uses, and some indication of probable development. The second part introduces the reader to the technical constraints of chemical cargoes, the methods of assessing the hazards, and the problems of product purity and reactivity that govern the safe and efficient carriage of any cargo. Part 3 discusses ship design, including important and changing rules such as MARPOL requirements, different building materials and different designs. Part 4 describes ship operations, Part 5 traces the development of chemical/parcel tanker fleets, and Part 6 contains useful appendices, for example on the uses of chemicals.

There is widespread interest in finding better and more cost-effective ways of procuring and maintaining naval platforms. Therefore there has been a great deal of interest in examining how other sectors of industry manage their business. The continued development of classification rules to specifically address naval surface ships is updated The opportunities are described which are offered to navies and suppliers by the adoption of a different approach to standards and specifications taken from the commercial sector that can be applied without constraining innovation. However the main objective is to show how the attributes of the classification system and in particular the well-established processes that form an essential part of classification can bring benefits to a naval project by providing effective risk management throughout the supply chain.

The Coal Industry Advisory Board (CIAB) commissioned its Infrastructure Committee to examine the constraints in and the relationship between the different components of the coal transport chain. The CIAB has now submitted its report, which is the outcome of a major effort involving coal producers and users throughout the OECD. The report is based on the experience of the practical problems encountered in coal transport by producers and users of coal located in different geographical areas of the OECD. It concludes that a suitable infrastructure must be available for the operation of the coal chain to support the needs of exporting and importing countries. It focusses on several weak spots in the coal transportation system and analyses the economics of different transport modes.

The reasons behind the decision by most major cruise lines to change to electric propulsion are described. In the commercial world the all electric ship was a natural development in the quest to build better performing ships. The problems with medium speed diesels driving a cpp steam turbines driving fixed pitch propellers and slow speed diesels driving a controllable pitch propeller (cpp) are outlined. The different propulsion plant were compared with reference to fuel consumption engine running costs and other issues. The decision by P&O Princess Cruises to use diesel-electric propulsion for Star Princess is discussed along with experience gained in terms of cost weight manpower space savings dynamic performance and noise and vibration.

Application of controlled weld toe profiles can be considered an option to extend the fatigue life of welded connections when ongoing tankers are converted in dry docks to serve like offshore ships (FPSOs and FSOs). Very slim chances to implement such fatigue improvement will arise when these vessels are in service since a converted ship is designed to be inspected maintained and repaired in situ and not in dry dock as it is uneconomical to interrupt production. A controlled weld toe profile can be applied in fatigue crack repaired welds during ship conversion or even on those that during ship conversion are found in a non-cracked condition but were identified prone to fatigue cracking in a stress assessment analysis under in-service conditions. Credit on fatigue life in various codes and results from experimental data obtained from fatigue tested specimens with a controlled weld toe profile are given. Comments on the design of a controlled weld toe profiles and recommendations based on experimental experience for the implementation of equipment to perform a controlled weld toe profile are also given.

Fuel consumption of ships is related to hull roughness. The increasing high cost of fuel is the driving force behind the effort that are expended in looking for methods, which would reduce hull roughness and would maintain a smooth hull surface profile during the designed life of a ship. One such desirable method involves the use of copper-nickel. This study examined a number of methodologies for applying Cu/Ni in sheet form. The welding of Cu/Ni clad steel was also evaluated in a shipyard environment. The cost differential between Cu/Ni sheathed and conventional painted hulls was determined for a large container ship. The economic analysis was based on 1980 cost figures and a specific application method of Cu/Ni hull sheathing. The results were 33.5% for the effective discounted cash rate of return and 4.2 years for the zero-interest breakeven point-against an initial incremental investment of $3.4 million using 46% tax rate.

A ship hull steel plate with fine-grained microstructure (SUF steel) has been developed to improve crack arrestibility and prevent catastrophic brittle fracture of hull structures in emergency conditions. A nonlinear FEM computer program was used to simulate the hull failure of a double hulled VLCC in collision and determine the plastic strain produced in the sheer strake upto fracture of the inner hull. Test samples of conventional EH36 and new SUF steel were characterised by chemical and structural analysis and tested for cracking behaviour after plastic strain by methods including the standard ESSO test the ultra wide-plate duplex ESSO test and the sheer strake model test: the results are used to compare crack arrestibility of the steels in conditions of plastic strain likely to promote brittle fracture. The contribution of SUF steel plate to the safety of ships and protection of the marine environment is considered.

Conf held 28 February to 4 March 1989 at Hotel Inter-Continental Miami Florida Papers are The outlook for the industry The impact of consolidation and merger on the market Overcapacity; a real or imagined threat to the cruise industry Where will the new pockets of demand be found for the cruise product Product versus price Effective advertising Cruise sales and distribution channels The demand outlook for the industry Cruise lines and ferry operations US flag cruise operations The cargo carrying cruise ship The new venture process in the cruise industry Cruise ship financial alternatives The insurance factor In search of new cruise destinations Notes on destinations requirements and destinations planning The air-sea alliance The Pacific The Caribbean Mexico Sales marketing & distribution Resilient mounting of large medium speed engines - a new dimension in the main propulsion know how General problem-solving of waste handling on board ships The contractor's role Satellite communications for a modern cruise industry

Most diesel driven ships and power plants have cleaning systems based on high-speed centrifugal separators for cleaning fuel oil and lubrication oil. So far there has been no adequate method to measure separation efficiency. A laboratory method developed by Alfa Laval is presented here that measures the separation efficiency versus the flow rate for centrifugal separators. Comparisons between the laboratory method and other tests using actual heavy fuel oil have shown that the correlation between separators is maintained but on different efficiency levels. By choosing a standard efficiency level set to 85% the recommended capacity can be standardised to the flow rate corresponding to this standard efficiency level.

Loading arms are increasingly being purchased for special applications requiring accurate and thorough specifications and considerable engineering assessment. This specification covers the minimum requirements for marine loading arms and their ancillary equipment for loading and/or unloading ships and barges at conventional marine terminals and sea islands. Part 1 - Specification - includes desctions on design and construction standards and practices; design details and requirements; materials; design; swivels and structural bearings; quick-connect/disconnet couplers (QC/DC); emergency release systems (ERS); accessories; hydraulic power systems; controls; electrical components; testing; quality assurance and quality control; and recommended documentation. Part 2 has tables and figures looking at, for example, ship details, ship motions, berth details, envelope details, control requirements, design load cases, loading arm arrangement and guidance to clearance check points. Part 3 contains guidelines to Parts 1 and 2. There are example tables and documents tucked into the back of the book.

This paper describes the development of a family of fast monohulls exhibiting very low resistance whilst being capable of simple steel construction. The family of designs can be configured to deliver capability either within the Operational Theatre or between Operational Theatres. It is designed to operate at an average speed greater than 40 knots and is capable of both long self-deployment range and high payload. High deadweight reconfigurable cargo space with rapid on and offload is an integral feature of the craft. Troop capability and aviation facilities are also included. These vessels complement fast air logistics and slower conventional marine logistics and deliver large payload over long ranges. This paper describes the original P2500 Ro-Pax and the family of fast commercial ships as well as the large Fast Naval Sea Lift Vessel FNSLV and the smaller Intra-Theatre Logistics Vessel ITLV.

This paper presents a simple system to measure five degree-of-freedom (DOF) motions of real ships in a seaway. In order to confirm the validity of the present measurement system a simulated motions and sensors arrangement installed on a wood plank is tested as a bench test in laboratory. Then the system is applied to a high-speed patrol boat to measure its 5 DOF motions in a seaway. Through a series of sea trials time histories spectral moments and statistic characteristics of 5 DOF ship motions are analyzed and the consistency as well as effectiveness of the present measurement system is discussed.