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Optimized damping to reduce noise on high speed-lightweight craft
AuthorsRaymond Fischer ; Leo Boroditsky ; Ronald Dempsey et al.
Date published2009
AbstractNoise levels are generally higher on high speed-lightweight craft than other craft due to their construction and high power-to-weight ratio. One effective method to reduce noise is the application of damping materials particularly on aluminum vessels. These damping materials both tile and spray-on can reduce both structureborne and airborne transmitted noise. Noise can be effectively controlled for minimal weight increase when the treatment thickness and coverage area are carefully optimized. This paper presents case histories of damping treatments applied to SEAFIGHTER (X-Craft) and a high-speed ferry patrol boat and crew boat. The techniques used to evaluate the damping material itself and incorporate the material's performance into a predictive tool are discussed. Damping to reduce noise induced by machinery and high-speed flow impact are also discussed.
AuthorsRaymond Fischer ; Leo Boroditsky ; Ronald Dempsey et al.
Date published2009
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Ormen Lange sub-sea condition and leakage monitoring
AuthorsJens Abrahamsen ; Svein Haugen ; Trond Benny Bertmand et al.
Date published2007
AbstractWith the Ormen Lange development Norsk Hydros sub-sea solutions are taking technological developments on the Norwegian continental shelf a significant step ahead. Nothing will be visible on the surface when the enormous gas field comes onstream in 2007. High pressure large water depth and distant location called for a new way of thinking in many ways. The leakage and CMS (condition monitoring system) developed to ensure safe and pollution free operation of the two templates at 850 meters water depth are presented. Back in 2000 Hydro and Naxys Naval Technology started the development of a new type of sub-sea monitoring system based on technology originally developed for naval warefare and surveillance. After successful testing on the sub-sea processing plant Troll Pilot in 2001 the system was further developed and qualified. On the Ormen Lange Templates one centrally positioned module containing an array of acoustic sensors monitors the complete 44 x 33-m template. The system provides location and magnitude of any leak structural vibration or valve malfunction on the template.
AuthorsJens Abrahamsen ; Svein Haugen ; Trond Benny Bertmand et al.
Date published2007
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Papers Presented at the Second International Symposium on Wave and tidal energy September 1981
AuthorsBHRA Fluid Enging
Shelf Location213d
AbstractSecond Int Symp held in Cambridge 23 - 25 Sept 1981 Papers are Environmental implications of wave power proposals for the Outer Hebrides and Moray Firth The spatial distribution of wave power on the western UK coast One dimensional modelling of tidal power schemes Mathematical modelling of tidal power in the Bristol Channel Surges in tidal power basins - can they increase power output Dynamic models of tidal estuaries A fluid transmission system for wave energy converters Wave energy - the influence of maintenance repair requirements Moorings for wave energy devices The influence of Severn tidal power schemes on sediment transport processes Environmental implications of tidal power proposlas with particular reference to the Severn Estuary Power generation from tidal flows for navigation buoys A hydrodynamical model of the Lancaster flexible bag wave energy device Extreme wave forces on submerged cylinders Turbine caissons for the Severn Barrage
AuthorsPublisherBHRA Fluid Enging
BHRA
Shelf LocationDate published213d
1981
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Performance analysis of pulsed loads on integrated power systems
AuthorsS D Sudhoff ; B Kuhn ; J Amy et al.
Date published2004
AbstractThis paper studies options for integrating Electro-Magnetic Rail Guns within the DD(X) Integrated Power System looks at simulation models developed to assess the impact of pulse loads on the electric plant performance and describes a reduced power test bed which can be used to validate simulation model approaches. Two basic configurations of pulse power converters are considered - a load commutated based converter reflecting various power factors on the electric plant and a combined uncontrolled rectifier-dc/dc converter based charger reflecting near-unity power factor on the electric plant. Each option is examined with and without the option of coordinating operation with the propulsion system. Also potential impacts to plant line-ups and ship-service power are discussed.
AuthorsS D Sudhoff ; B Kuhn ; J Amy et al.
Date published2004
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Prediction on aging of reconstitutive clayey marine soils using fuzzy-logic
AuthorsJorge Sanchez Moreno ; Edison Castro Prates de Lima ; Gilberto Bruno Ellwanger
Date published2003
AbstractThe main objective of this paper is to present an application of fuzzy logic theory to predict the depth variation of the soil strength by aging effect. The results of experimental tests with reconstituted clayey soils of the Bay of Campeche were used to generate the fuzzy rule-based system. The artificial soil was made with a suspension adding marine water and was left in free sedimentation and consolidation processes. After this triaxial testing type Consolidated-Undrained (CU) was carried out on samples so the measurement of the shear strength could be made through the time. The fuzzy logic model is based on a decision (inference) process that can be better described on a linguistic level using rules with soft facts.
AuthorsJorge Sanchez Moreno ; Edison Castro Prates de Lima ; Gilberto Bruno Ellwanger
Date published2003
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Report of the investigation into the lifeboat accident on Pride of Hampshire on 25 September 1994
AuthorsMarine Accident Investigation Branch (MAIB)
Shelf Location15d
AbstractThe ro-ro passenger ferry Pride of Hampshire was berthed at Cherbourg when No 2 lifeboat launching equipment failed whilst the crew were undergoing lifeboat drill. 16 of the 32 occupants were taken to hospital. Examination of the damaged davit structure found that welded joints were of inferior quality with incomplete penetration and lack of fusion. This report includes the sections Factual Account (particulars of the vessel and crew and a narrative); Considerations of Possible Factors (including extent of damage to no. 2 lifeboat launching installation, metallurgical examination of the suspension links and pivot pin boss weld joints, Marine Safety Agency requirements for lifeboat launching equipment blocks and attachments, quality assurance) and Conclusions (findings and recommendations).
AuthorsPublisherMarine Accident Investigation Branch (MAIB)
London : Her Majesty's Stationery Office (HMSO), 1996.
ISBN number115518711
Shelf LocationDate published15d
1996
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Requirements made on integrated transport systems - APL takes on the future: integrating the Pier 300 Terminal in Los Angeles
AuthorsJ Truchan
Date published1996
AbstractThe establishment of carrier alliances with dedicated facilities as a means of reducing costs maximising assets and providing an efficient reliable and cost effective service to customers is discussed. Pier 300 the new Los Angeles multi-carrier terminal under construction for American President Lines and designed to meet the needs of the Global Alliance of container carrying companies is described with details of the equipment and operating systems associated with key items of work flow including Gate Yard Cargo Handling Machinery Vessel/Rail/Truck and Customer: potential for further automation is also considered. The establishment of carrier alliances as a means of reducing costs maximising assets and providing an efficient reliable and cost effective service is discussed.
AuthorsJ Truchan
Date published1996
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Research on Applicability of New Materials to Marine Structures in Tropical Climates - Exposure of Structural Materials at Okinotori-Shima
AuthorsF Tomosawa ; S Tsujikawa ; T Nakatsuji et al.
Date published2001
AbstractThis study aims to investigate the applicability of newly developed lightweight structural materials having high durability to marine structures from the standpoint of their lifecycle cost focusing on the corrosion resistance of such materials. The material selection specimen fabrication and initial performance testing of specimens have been completed so far and exposure tests are being carried out at Okinotori-shima Miyako-jima and in a laboratory in Tokyo. This paper reports on the outline of the exposure tests and the results of tension tests on metallic materials.
AuthorsF Tomosawa ; S Tsujikawa ; T Nakatsuji et al.
Date published2001
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Seafloor geodesy and an ocean-bottom cable system
AuthorsHiromi Fujimoto
Date published2003
AbstractSpace geodetic technologies such as GOS VLBI (very long baseline interferometry) SLR (satellite laser ranging) and SAR (synthetic aperture radar) have revolutionised geodesy on land. However these technologies based on electric waves cannot be directly applied to seafloor geodesy because electric waves inclusive of light can hardly propagate the seawater. Sound waves and ocean-bottom cables have to be adopted for underwater communication positioning power supply and data recovery. The importance of crustal movement on the seafloor has long been known and how there are promising reports on GPS or acoustic seafloor positioning repeated acoustic ranging on the seafloor ocean-bottom pressure monitoring and tilt measurements in deep-sea boreholes. Long-term continuous and regional observation is crucial for geodetic monitoring of geodynamics. Now is the time for a new plan of scientific ocean-bottom cable system to be examined. Although global coverage is difficult trans-ocean monitoring systems or regional systems over seismogenic zones are feasible. The latter can maintain real-time observations on the seafloor which are crucial for studying how a big earthquake is prepared.
AuthorsHiromi Fujimoto
Date published2003
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Structureborne noise control on cruise ships
AuthorsG Besio ; V Loredan
PublisherIMarE Conferences and Symposia
AbstractTaking diesel-electric cruise ships as a reference this paper illustrates the procedure followed by Diesel Ricerche SpA to limit the structure borne noise problem on the hull foundation where target values are quite strict. Each ship is powered by five gensets three of which are engined with GMT-Sulzer 8ZAL40S and the other two with 12ZAV40S. In each set the engine and the electric machine are rigidly mounted on a common raft and each is connected through an elastic coupling. The raft is resiliently mounted on two rows of sandwich type inclined mounts. As a result of a preliminary acoustic estimation of the ship the noise level was high at middle-range frequencies and methods of noise reduction for the system are examined.
AuthorsDate publishedG Besio ; V Loredan
1993
PublisherIMarE Conferences and Symposia
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Study of wave load nonlinearity effect on fatigue life in component stochastic fatigue analysis
AuthorsSungkon Han ; Kyung-Won Park ; Hyun-Il Shin
Date published2004
AbstractThis paper addresses details of wave load nonlinearity effect on stress RAO and damage ratio using component stochastic fatigue analysis. Traditional spectral fatigue analysis for ship structure is based on linear theory; however there are a number of nonlinearity sources. Especially loading nonlinearity such as hydrodynamic pressure applying to ship side and gravity changes due to roll and pitch motion is thought to critically violate the linearity assumption of spectral fatigue analysis which involves stree RAO as linear parameter. The main focus is placed on how to idealize complicated characteristics of loading nonlinearity and how to implement the nonlinear bias to linear spectral fatigue analysis.
AuthorsSungkon Han ; Kyung-Won Park ; Hyun-Il Shin
Date published2004
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Study on optimisation of automatic control parameters for Ekranoplan WIG ship
AuthorsQian Zhou ; Xing-fa Xu ; Chang-hua Yuan
Date published2006
AbstractA method is introduced that is based on the space motion equation of Ekranoplan for optimising automatic control parameters. Firstly the space motion equation of Ekranoplan plus Automatic Control System is established. Next MATLAB is chosen as the main software support for establishing the mathematical model of optimisation system with the help of its non-linear multi-variable function fmincon 0. Finally the optimum procedure of automatic control parameters is programmed on the platform MATLAB-GUIDE and the optimisation calculation of automatic control parameters can be carried out. The results show that through optimisation calculation of automatic control parameters of ekranoplan optimal results may be achieved and for solving the questions of dynamic stability and manoeuvrability of Ekranoplan it is unnecessary purely to depend purely on the aerodynamic design.
AuthorsQian Zhou ; Xing-fa Xu ; Chang-hua Yuan
Date published2006
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Tagging juvenile seabass and sole with telemetry transmitters: medium-term effects on growth
AuthorsM L Begout Anras ; D Coves ; G Dutto et al.
Date published2003
AbstractThe effects of tagging with acoustic transmitters on the growth of juvenile seabass in a 47 d tank experiment and sole in a 72 d tank experiment and in a 58 d salt marsh mesocosm experiment were examined. Twenty externally tagged seabass grew more slowly than the 20 with surgically implanted tags which reached the same mass as nine control fish. Movements of the external transmitter's harness caused abrasions of the skin and loss of the tag in 60% of cases. The external tag also induces extra drag forces for which the fish must compensate. The experiments concluded that for juvenile sole the externally attached tag retention rate was good but at the expense of fish growth rate. This paper presents experiments on the medium-term effects of tagging on growth of juvenile seabass and juvenile sole.
AuthorsM L Begout Anras ; D Coves ; G Dutto et al.
Date published2003
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The development of an ISO standard for specifications and performance tests of on-line monitors/sensors for water quality
AuthorsA Lynggaard-Jensen
PublisherNational Engineering Laboratory
AbstractResults of work carried out in a European research project and in a working group under ISO (International Standardisation Organisation) are presented; a draft of a technology independent standard for testing the performance characteristics of on-line monitors/sensors for water quality parameters is described. The standard can be considered as a horizontal standard covering the measurement of any water quality parameter. Using the definitions of the performance characteristics will enable users and producers of on-line monitors/sensors to define a vertical standard for a certain parameter even in a given application. The standard can also be used in certification schemes and in running supervision of the operation of on-line monitors/sensors.
AuthorsDate publishedA Lynggaard-Jensen
2001
PublisherNational Engineering Laboratory
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The effect of a foul release coating on propeller performance
AuthorsM Atlar ; E J Glover ; M Candries et al.
Date published2002
AbstractThe 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.
AuthorsM Atlar ; E J Glover ; M Candries et al.
Date published2002
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The Effect of Attachment Plate Thickness on Fatigue Crack Shape Development in Welded T-Plate Joints
AuthorsR Yee ; Y Huang ; S B Lambert et al.
Date published1998
AbstractThe effect of attachment thickness on the fatigue behaviour of T-plate welded joints subjected to constant amplitude three-point bending has been examined using both experiments and numerical simulations. In the experiments fatigue crack initiation propagation and coalescence was monitored using DC potential drop techniques in combination with ink stains and beach marks. This detailed crack shape development data has permitted the development and verification of a probabilistic fracture mechanics model for the initiation growth and coalescence of fatigue cracks in welded joints using a Monte Carlo technique. In this paper these experiments are used along with detailed simulation results to explore the effect of attachment plate thickness on fatigue in welded T-plate joints. The important role of crack shape development on these simulations is discussed.
AuthorsR Yee ; Y Huang ; S B Lambert et al.
Date published1998
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BSRA Technical Memorandum No. 127 Reports on foreign observers' course on the nuclear ship 'Savannah'. Shipyard Practice
AuthorsJ A Dodd ; S Macdonald
Shelf Locationin storage
AuthorsPublisherJ A Dodd ; S Macdonald
British Ship Research Association
Shelf LocationDate publishedin storage
1960
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Development of Shipbuilding on the Upper Reaches of the Clyde (2nd copy - in Archive, first copy on shelf 21)
Catalogue number720.117
Catalogue number720.117
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Report on the investigation of the contact between Pride of Provence and The Southern Breakwater, Dover Harbour, eastern entrance on 18 April 2003
AuthorsMarine Accident Investigation Branch
Shelf Location40d
AuthorsCatalogue numberMarine Accident Investigation Branch
UNK
Shelf Location40d
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Automation in ships - Symposium on Automation in Ships
AuthorsRudolf Kempf
Shelf Location212g
AbstractSymposium held in Newcastle 15 October 1974 and in London on 17th October, 1974, on Automation in Ships.
AuthorsPublisherRudolf Kempf
Rudolph Kempf
Shelf LocationDate published212g
1974