Search our collections

Multi-hull vessels have emerged as popular alternatives to conventional mono hull ships for high-speed crafts. However the bridging structures connecting the hulls are vulnerable to various wave actions and the wave impact to the bottom of these vessels is the most serious problem. In this study prediction of the relative wave elevations under bridging structures is investigated for multi-hull ships travelling with forward speed in waves. A computer code YNU-SEA of 3D Green function method with forward speed has been developed and used to analyse the hydrodynamic radiation and diffraction forces and motion responses for high-speed catamarans in waves. The results of present calculations are compared to those of the previous calculations as well as with the experimental ones. Numerical results reveal that the present computer code has the practicality to be a powerful tool for the accurate numerical computations of sea keeping problems of multi-hull ships advancing in waves. Numerical calculations of wave pattern are also carried out including wave interactions between the hulls to analyse the effects of hull form on the free-surface flow around catamarans advancing in waves. The analysis of the wave pattern allows the determination of relative wave height including radiation and diffraction waves. Finally discussion based on these numerical results is presented which may be helpful for the accurate prediction of relative wave height and wave breaking load on the deck associated with multi-hull ships.

Wave-impact related (slamming) loads can induce high stresses and cause deformation of local structural components. The accurate assessment of such loads is essential for the design of a ship's structure. Classification society rules contain formulas for slamming loads. Generally these formulae are adequate for conventional ships as they are based on operational experience. However for many modern ships it becomes necessary to resort to direct computations of slamming loads. A satisfactory theoretical treatment of slamming has been prevented so far by the complexity of the problem. Most theories and their numerical procedures were applied on 2D bodies; however slamming is a strongly 3D non-linear phenomenon that is sensitive to the relative motion between the ship and the water surface. Slamming is characterised by highly peaked local pressures of short duration. A numerical procedure to predict impact-related wave-induced (slamming) loads on ships is presented. The procedure was applied to predict slamming loads on two ships that feature a flared bow with a pronounced bulb hull shapes typical of modern offshore supply vessels. The procedure used a chain of sea-keeping codes. First a linear Green function panel code computed ship responses in unit amplitude regular waves. Wave frequency and wave heading were systematically varied to cover all possible combinations likely to cause slamming. Regular design waves were selected on the basis of maximum magnitudes of relative normal velocity between ship critical areas and wave averaged over the critical areas. Second a non-linear strip theory sea keeping code determined ship mot100094 Numerical prediction of model podded propeller-ice interaction loads

Clippings tucked inside.

Recommendations for automatic and remote controls in ships having unattended machinery spaces. Includes the following applications: oil fuel systems, steam generating plant supplying steam to propulsion machinery, ships propelled by oil engines, evaporating and distilling plant, fresh and distilled water systems, electric generating plant, controllable pitch propellors. Includes sections on fire precautions and construction, installation and commissioning and testing of control equipment.

NOx and SOx marine emissions are considered. Current atmospheric conditions in Japan are examined followed by fuel consumption in ships and the ratio of atmospheric pollutants contributed by ships. A dispersal simulation of atmospheric pollutants from ships is presented. Future regulatory trends regarding ship emissions are examined. Theories and technologies necessary to reduce atmospheric pollutants and to comply with future regional restrictions are explored.

These regulations enumerate the main requirements and precautions for ensuring satisfactory results, including safety from fire and shock, relate to the generation, storage and distribution of electrical energy for all purposes in sea-going ships (except ships of war). Various methods of accomplishing the electrical equipment of ships are provided for. Only existing proved materials, appliances and methods are considered.

Covers the history and development of sailing ships from the early ships of the Mediterranean littoral through to the evolution and decline of the clipper ship.

The book describes the factors that contribute to the actual design of ships, yachts and boats. It is concerned with why ships have taken their various forms and what influences and forces have guided these forms. It also describes how a ship's form is defined on paper and the complicated procedures of the testing tank. There are further chapters on decoration; the effects of crafts, tradition and science; the future of ships; pure speed; racing yachts; and lastly the twentieth century naval dilemma.

It has long been recognised that the overall efficiency of ships in performing any given service is closely related to the time spent in that service. The object of this paper is to present a method of evaluating the cost of ships' time that can be used to evaluate predictable delays or time-savings to ships and to accompany this by the results of applying it to a sufficient number of ship types and sizes for relevant values to be tabulated in a convenient form.

The book's particular purpose is to indicate the design considerations in the use of aluminium for ships with special reference to the design of superstructures, and it includes appropriate discussions of constructional techniques. Chapters look at: Types of shipbuilding alloys including aluminium, the Availability of materials including ranges of sections, Classification Societies and aluminium alloys, Design considerations, Buckling of aluminium alloy structures, Strength of superstructures, Joining of aluminium parts, Minor structural parts and equipment, Fire protection in passenger ships and The influence of the use of aluminium alloys on the design of ships.

The recent development of ro-ro passenger ferries is considered. Application of SOLAS 90 and the Stockholm Agreement is discussed for both newbuildings and existing ferries by describing typical two examples. Space below freeboard deck; centre or side casings; rational cargo handling; efficient arrangement for trailer ferry; damage stability; and upgrading existing ro-ro passenger ferries are all areas investigated.

A description is provided of how the provisions of classification are applied to naval ships and how Lloyd's Register's Rules and Regulations for the Classification of Naval Ships have been developed. The development of a flexible system which meets the needs of different navies to enable them to bring within the scope of classification specialised ship structures and engineering systems is presented. First a look is taken at the classification process followed by naval ship classification. Next military aspects are considered. After this commercial standards and international conventions are looked at.

Many issues impact the acoustic posture of a newly constructed vessel. The primary acoustic concern for oceanographic or survey type ships is to minimise the impact that ownship noise may have on installed sonar equipment. Ship acoustics are discussed together with how they evolved in the USNS PATHFINDER (T-AGS 60) class ship acquisition program. During the initial ship delivery process for this program it was determined that the acoustic posture of these ships was inadequate to support the mission requirement of deep-water bottom mapping. A comprehensive investigation was conducted and problem areas were identified. The findings of that investigation are summarised together with subsequent ones to fully document the acoustic issues that were present on this new class of ships. Additionally the modifications and improvements that were made to these hulls are addressed to stress the importance of vessel acoustic posture and how it relates to mission performance with respect to acoustics. The types of modifications that are addressed are: sonar fairing design; paint and hull conditions; propeller cavitation performance; hull appendages; bubble sweepdown and general acoustic requirements. Acoustic measurements and levels are provided as well as specific measures of system performance.

The USS Burke (DDG-51) Destroyer entered service in 1991. Since then over 50 ships of this design have been constructed. The production of these ships is to end in a few years with DDG-112 however these vessels will be serving in the US fleet for many years to come. They have received numerous upgrades over the years to keep pace with new and emerging threats yet the propulsion and electric power plant has remained largely unchanged. While this mechanical drive train has proved itself to be very reliable the design suffers from poor fuel economy when compared to other warships. Consequently there has been recent interest in exploring the addition of new technology such as hybrid electric drive or 'loiter motor' to improve the efficiency of these ships. The operational concept for adding a hybrid electric (COGLOG) drive system to the existing ships is explored a number of technologies for implementing such a system are examined and the potential for significant fuel savings is demonstrated if such as system were fielded. Both fuel savings and TOS (time on station) improvements for implementing a hybrid drive on the DDG-51 are noteworthy and will be reviewed.

The feasibility of using free-fall lifeboats on passenger ships is evaluated with discussion of: development of the concept from first patent to current implementation on cargo ships mobile drilling rigs and offshore structures; SOLAS carriage requirements for passenger ships placement implications and cost differential (comparison is made with conventional davit launched equipment); the need for crew and passenger training in the use of free-fall restraint systems; and the recent findings of an IMO panel of experts on RORO safety. Concluding remarks consider free-fall lifeboats to be inappropriate for general use on passenger ships but concede some specialist applications.

In order to develop rational and transparent procedures for the structural strength assessment of container ships which can offer consistency of approach to shipbuilding marine and related industries as well as improve container ship safety a series of comprehensive studies has been carried out by ClassNK in recent years and some of the results are summarized in this paper. The comprehensive study on the design loads for direct strength assessment of primary structural members of container ships was firstly introduced. Secondly a comprehensive study on the method for torsional strength assessment of container ships is discussed based on the results from direct torsional moment analyses by a 3-D Rankine-source method and FE analyses of the entire ship structures. Lastly outlines of some basic studies such as 3-D numerical simulation for very strongly nonlinear ship-wave interactions in extreme waves full-scale measurements of hull response of a post-Panamax container ship in service etc. are also introduced.

Some information on modelling safety of ships in damaged conditions at the preliminary design stage is presented by using an alternative performance-orientated risk-based method. The performance-orientated risk-based method of assessing safety of ships including modelling is briefly discussed. Some examples of safety assessment for two container ships using the proposed method are presented. The method uses the performance-orientated risk-based approach. The elements of safety case and FSA (formal safety assessment) methodologies are incorporated within the method. The hazard identification scenario development ship hydromechanics analysis risk estimation and risk control options are combined. In this respect the method is a risk-based design method as it integrates the systematic risk analysis in the design process with the reduction of risk embedded as a design objective. The method may be implemented as a design for safety method (including safe operation) or salvage-orientated method.

Experience gained in operation ro/ro ships has enabled the International Maritime Organisation (IMO) to develop standards to improve the safety of this type of operation. This code, which includes the standards developed by the IMO, provides guidance and information on safe procedures to be followed during roll-on/roll-off operations to reduce risk to persons and ships. Section 1 looks at the principal sources of danger; section 2 at protection of personnel on ramps and vehicle decks; section 3 at vehicle decks, ships' ramps, lifting appliances and securing arrangements; section 4 at vehicles - suitability for transport by sea; section 5 at stowage and securing; section 6 at specialised vehicles and cargoes; section 7 at the Cargo Securing Manual; and section 8 at related publications.