Search our collections

In the last 10 years the application of gas-lubricated compliant bearings has begun in power installations. The use of these bearings allows oil to be removed design bearing units to be simplified friction loss to be reduced and reliability to be increased. The application of turbo-compressors on gas-lubricated compliant bearings on vessels is restrained because of the restricted resource of bearings which directly depend on dynamic loads on the bearings caused by the imbalance of a rotor the vibration of a propeller and also onboard and pitching of a vessel. In order to develop operational ship turbo compressors it is necessary to develop design procedures of amplitude of forced oscillations of a rotor caused by a spectrum of excitation sources of vibration. The methods of research are described.

This study aims to investigate the applicability of new materials to marine structures focusing on their durability. To this end a 5-year exposure test has been conducted from 1999 on 3 types of specimens (for corrosion observation tension testing and joint strength testing) made of 21 selected materials (6 nonferrous metals 8 steels 4 composite materials and 3 rope materials). The specimens are exposed at 3 sites: Okinotori-shima and Miyako-jima corrosive environments with high temperature and humidity and a thermo-hygrostatic room in a laboratory. This paper reports on the results of appearance observation of specimens at Okinotori-shima and Miyako-jima carried out mostly in 2001 as well as the findings from observation and experiments on specimens exposed for 2 years at Miyako-jima.

After the 1930s a great many bridges with a span of 500 meters or more were constructed throughout the world. In the 1970s large oversea bridges began to be built in Japan and this brought about diverse changes in the environment of the marine space. Around this time a problem arose with the lighting of the oversea bridge in the Seto Inland Sea in the waters near the bridge. This caused problems with the safety of the navigation of vessels. A research project is presented which was undertaken to investigate the impact on the safety of vessels operating in the waters near the Honshu Shikoku Bridge at night and the level of its impact on fishing activities in these waters. This research was based on an evaluation by those using the waters and verified the validity of measures concerning the impact of light from the Honshu Shikoku Bridge. The survey found that the impact of the lighting of the Honshu Shikoku Bridge on nighttime fishing activities is small. However it is believed that the visibility of the light of other vessels and maritime signs during vessel operations is impaired.

A-type engines have been built for over 17 years as both in-line and V-versions. They have been fitted in numerous marine and stationary installations and their design and output were adapted to the changing requirements including operations on heavy fuel oil. The paper gives the service summary for this universal type of engine operating on heavy fuel oil details related design aspects. The lubricating oil system main and bottom-end bearing life cylinder liner wear piston wear cylinder head and valves operation and fuel injection system are discussed. Low-load operation and shut-downs on heavy fuel are outlined. Some reference is also made to engines operating on marine diesel oil.

The 1995 Hyogoken-Nambu earthquake caused severe damage to many structures in the bay area. The damage to shore structures was due to liquefaction. Here the focus is on the sheet pile quay wall which is a typical type of shore structure. The seismic behaviour of the structures when liquefaction occurs is considered by applying the dynamic response analysis and a simplified prediction method. Firstly based on the case study by the dynamic response analysis the influence of the input earthquake motion on the residual deformation of sheet pile quay wall is discussed. As a result it is confirmed that the residual horizontal displacement of top of sheet pile depends on the maximum horizontal acceleration and the degree of stiffness of back fill. Secondly the applicability limit of the simplified prediction method was discussed by comparing it with the dynamic response analysis. The simplified analysis is applicable as a prediction method for seismic behaviour of sheet pile quay wall by considering the influence of the semi-liquefaction.

The purpose of magnetic measurement is to understand the Earth's interior material distribution and to provide the basic data and maps for underwater navigation and for magnetic object detection. The change of local geomagnetics can be expressed by the LGFM (local geomagnetic field model). In constructing the LGFM more attention is paid to the quality of geomagnetic data and the methods of building the LGFM. According to the characteristics of the magnetic modelling methods the methods of building LGFM can be divided into three categories: surface fitting or approximation; surface interpolation; and the method based on geomagnetic potential theory. The first two of these methods are geometric methods while the third has a physical meaning. The experiments and theoretic analysis show that surface fitting is the most simple of the three methods. This is very important in underwater magnetic navigation as the geomagnetic background can be filled in using this method and the location of the underwater carrier can be determined using the ICCP (iterative closest contour point) algorithm.

Oil spill can have a serious impact on coastal activities and on those who exploit the resources of the sea. Simply the effects of oil on marine life are caused either by the physiological nature of the oil or by its chemical components. The most toxic components in oil tend to be those lost rapidly through evaporation when oil is spilt. Because of this lethal concentrations of toxic components lead to large-scale mortalities of marine life. Dispersants are oil spill response chemicals that are used to disperse floating oil in the water column. In this study the new oil dispersant Par 1 was examined on 28-32 g rainbow trout. 96 hours acute toxicity of oil dispersant by itself and oil and dispersant combinations were tested in various concentrations. The effectiveness of Pars 1 was compared with Gamlen OD4000. By calculating the RET value and bioassay studies the high effect and efficiency of Pars 1 has been proved. Materials and methods are presented. Results are given and discussed and conclusions drawn.

This work deals with a numerical and experimental investigation on the effect of the reeling installation process on the collapse pressure of API X steel pipes. A three-dimensional nonlinear finite element model is first developed to simulate the bending and straightening process as it occurs during installation. The model is then used to determine the collapse pressures of both intact and plastically strained pipes. In addition experimental tests on full-scale models are carried out in order to calibrate the numerical model. Pipe specimens are bent on a rigid circular die and then straightened with the aid of a custom-made test facility. Subsequently the specimens are tested quasi-statically under external pressure until collapse in a pressure vessel. Unreeled specimens are also tested to complete the database for calibrating the numerical model. The numerical model is finally used to generate collapse envelopes of reeled and unreeled pipes with different geometry and material.

In the past few years new engines have been added to the MC series. For large container ships the K98MC and K98MC-C engines have been developed and on testbed the 12-cylinder version has delivered more than 100000 bhp on one shaft. Solutions to power requirements in excess of 125000 bhp are presented. Design improvements introduced on the S80MC-C and S90MC-C engines developed for VLCC ships are also presented. The new design is discussed (with emphasis on large bore engines) and focuses on the frame box bedplate and main bearing assembly. Extended use of advanced calculations verified on testbed secures the reliability of the new design. On all large bore engines a new combustion chamber has been introduced which involves a complete redesign of piston crown

This paper complements a 'live' demonstration of the on-line version of the HCR (Offshore Hydrocarbon Releases) system which can prove useful in analysing offshore hydrocarbon releases. The latest web-based version gives offshore duty-holders access to the HCR system to allow submission of incident reports direct into the HSE databases. It also contains facilities to generate tailored reports on-line. The reports include the generation of generic leak frequencies for installations systems and types of equipment together with various graphs and tables previously only available on an annual basis. The raw incident data for any year from 1992 can be viewed on-line and is also downloadable to enable users to carry out their own detailed analyses.

Fourth Int Conf held in Warwick on 5 - 8 April 1982 Papers are Trends in system design techniques Truly distributed control using one microprocessor per real time task On line digital control systems for high voltage subtations Viewdata as a control tool The application of redundancy in controllers for high capital cost or high integrity plant System - cost/redundancy trade offs in on line control Functional and geographical distributed control of industrial processes Improved fault tolerance in microprocessor based control systems result from the use of a bus collator A fault tolerant communications ring for on line distrubuted control systems Development and application of adaptive control methods in continuous casting plants An intergated approach to the management and development of computer based systems Specification and evaluation of programmable process control systems Monoliths out - distributed micros in Review of experience gained in the implementation and operation of a data acquisition and control scheme monitoring the River Thames catchment area The computer and control yesterday today and tomorrow A communication technique for distributed control systems The rising IQ of telecontrol RTUs Development in software technology Structured programming in assembly language gives efficient object code Integrated language approach to simulation and control The application of process orientated software to a blast furnace

Results are offered of an accident investigation conducted on occupational injuries occurring to fishermen employed on small fishing vessels (about 20m in length) in South Italy. Also an investigation on quality of working conditions and on lifestyle has been carried out by means of questionnaires handed to fishermen. After an introductory look at the fishermen the fishing industry and risks/dangers The Italian fleet is briefly addressed. Next working conditions health and lifestyle are looked at followed by accident investigation. Vessel seaworthiness and working conditions are considered. Lastly attention is given to tools for the improvement of safety and health in the fishing industry - ergonomic aspects.

Electrical power networks for alternating current are often designed as three-phase systems. An advantage of such systems is the possibility of a balanced power distribution over the three phases. As a consequence the power generator has a continuous load. Furthermore the neutral lead does not carry or barely carries current because the currents through the phases cancel each other out. The situation becomes different when the alternating current is no longer sinusoidal. This occurs when the power demand becomes more pulse shaped. Equipment showing this behaviour includes such office equipment as computers energy-saving lighting power converters commercial appliances such as photocopiers and printers. The use of such equipment is growing also in the maritime market. A characteristic of this equipment though is that the pulses are at fixed-phase shifts with the AC power from the generator. This means that the power system faces significant higher harmonics particularly third and fifth harmonics. An in-depth analysis of pulsed power demand effects on an AC network is reported. The load on the generator is discussed as well as the current in the supposedly neutral wore and branch networks. It concludes on relevant design issues in the light of growing pulsed power demand that would benefit installers and system integrators amongst others.

Marine propulsion shaft alignment using the strain gauge alignment technique is becoming more commonplace as shipyards and owners find the technique is accurate reliable and cost effective. There are a number of advantages of incorporating this technique on slow-speed diesel propulsion shaftlines. Accurate measurements of both the vertical and athwartships loads on the lineshaft and sterntube bearings can be obtained while the shaft is completely assembled. Direct measurement of the shear and bending moment at the thrust shaft flange can also be obtained to ensure the load on the aft-most engine bearing is acceptable. Measurements can usually be obtained within thirty minutes enabling shaft alignment to be evaluated at various loading conditions and machinery temperatures without significantly interfering with operations or production. The strain gauge alignment technique has also been shown to be more accurate and less time consuming thant the traditional method using gap and sag and jack-up load measurements. The strain gauge alignment technique was incorporated into the alignment procedures for the Pure Car Truck Carrier "MV Jean Anne" built by VTHalter Marine Inc. and the first two CV-2600 container vessels built at Ajer Philadelphia Shipyard. This paper describes the measurements and results of the strain gauge alignment technique used for two classes of vessels.

The effect of a finite Froude number on the performance of fully cavitating foils in the vicinity of the free surface is investigated. A solution is obtained using a distribution of Kelvin sources and vortices along the mean line of the foil-cavity system. In this way the correct free-surface conditions on the cavity surfaces and on the water surface are satisfied. The convergence rate is found to be inversely proportional to the number of singularity elements used and this fact can be used to extrapolate the results for higher accuracy. The effect of the Froude number is found to be more important when the cavity length is greater. For example when the cavity length is eight times the chord of a flat foil and the foil submergence equals the chord the lift co-efficient is found to be 21% less at a Froude number of 2.828 compared with the infinite-Froude-number calculation. The cavitation number is found to be 72% less in the same condition. It is also shown that in the range of interest the infinite-Froude-number results can be corrected by a term which is proportional to the inverse-square of the Froude number. Large distortions in the cavity shapes by the Froude-number effect are also predicted by the method. Concluding remarks are presented and further work identified.

The development of spar platforms for offshore gas and oil exploitation and production has been ongoing since Neptune production spar was installed in GOM by Kerr-McGee in 1996. Among those spar concepts put forward by the design companies and institutes the classic spar and truss spar are the most prevalent. The cell spar is a new design and now operated in Texas. For the sake of installation of rigid risers with dry wellhead motions of the spars should be confined in a certain range. Haslum and Faltinsen proposed that the wave frequency response might be reduced in three ways: 1) by increasing the damping of the system; 2) by increasing the natural heave period out of the range of the wave energy; and 3) by further reducing the linear heave excitation forces. An experimental study on the effect of heave plates on the hydrodynamic performances of a cell spar platform is presented. A variation of the cell spar concept whose hard tank still consists of several cylinders (cells) with the same diameter and length but whose lower part is fitted with a truss section and several heave plates is modelled and tested. As the effectiveness of heave plates is crucial to the heave performance different types of heave plates are fitted to the truss structure varying from the number and spacing to the form such as perforated plates to investigate various design aspects of the plates. Experimental results and numerical predictions for the responses of the spar to the wave loading as well as loads and added mass and damping coefficients on the heave plates are presented.

Ship propulsion trials in ice were carried out in the Antarctic in January 1995 during the USCGC Polar Star's mission to re-supply bases along the Antarctic Coast which included extensive icebreaking in McMurdo Sound. This project the measurement of ice loads on a propeller blade of the largest controllable pitch propeller icebreaker in the world is the latest of many collaborative arctic research and development projects over the years between the Canadian and US Coast Guards. The objective of the trials was to measure the ice and propeller interaction loads on one starboard propeller blade and the corresponding propeller shaft of the vessel. A comprehensive analysis of the data was then carried out in order to determine the influence of design operational and environmental parameters upon the nature and magnitude of the ice loads. This paper concentrates on the application of the results to regulations and most importantly to the IACS Unified Requirements supporting the IMO Polar Code.

Symp held in Hamburg 5 - 9 Dec 1977 Papers are Todays great paradox - the wealth of the seas and the shipping crisis Philosophy and safety requirements for land based nuclear installations An NEA confrontation to the safety of nuclear ships The international state of affairs in marine safety Development of a nuclear ship safety philosophy Application of risk assessment to nuclear merchant ship safety Port interface requirements Ship accident studies A mathematical model for the analysis of the protection barrier of nuclear ships Effects of ship casualties on reactor safety and marine reactor design Conclusions from collision examinations for nuclear merchant ships in the Federal Republic of Germany Flooding and sinking of nuclear merchant ships Heat removal from the reactor pressure vessel to the surrounding seawater in case of sinking A role for probabilistic methods in nuclear ship safety Safety studies on loca for N S Mutsu Development of accident event trees and evaluation of safety system failure modes for the nuclear ultra large crude carrier Start up test and technical problems encountered on N S Matsu N S Otto - non destructive retesting (in service inspection) Engineered safety equipment and safety analysis of NCS-80 Handling loss of coolant accidents in the IPWR In service inspection programme for the NCS-80 reactor pressure vessel

Zeke's Island part of the North Carolina National Estuarine Research Reserve is an undeveloped site. The Reserve site is owned by the State of North Carolina and managed by the North Carolina Department of Environment and Natural Resources Division of Coastal Management as part of the Coastal Reserve Program. State statutes and rules allow compatible recreational uses and other activities on the Reserve. Although a fairly pristine and isolated reserve site the Zeke's Island Reserve is located near the communities of Wilmington Carolina Beach and Kure Beach. These communities attract significant numbers of in-state and out-of-state tourists and local residents each year. Many of these tourists and residents choose to recreate on the Zeke's Island Reserve due to its less crowded undeveloped character and nature. The effects of various recreational activities are investigated in a study. Based on the results it is concluded that the passive use of regulatory signs is an effective management tool in regulating visitor behavior within the Zeke's Island Reserve.

In future the electrical power generation on the navy's AES (all-electric ships) will have increased significantly. This will lead to higher short-circuit currents in these ships' power systems. Therefore components carrying the short-circuit currents will be exposed to higher mechanical and thermal stress. The sources of power available to produce fault current into a fault on a ship power system will be limited by the presence of PE (power electronic) converters which can rapidly control current flows. Issues are illustrated that may arise if medium-voltage class FCL (fault current limiters) are introduced on navy type AES (all-electric ship) power systems as well as the modelling of that system for various transient simulation studies. The system is modelled in detail with all power electronic converters in place. Later these complex models are replaced by simpler average load models and validated against the detailed model. A model to represent the FCL in terms of variable impedance is modelled and validated against published data from measurements. Different configurations of FCL placements within the power system are considered and simulation results are presented. The need to consider different operating conditions of the power system and the need to evaluate the protection system setting when FCLs are added are identified. The simulations are carried out in the industry standard transient simulation program PSCAD-EMTDC. Results are presented and conclusions drawn.