The Experts below are selected from a list of 114 Experts worldwide ranked by ideXlab platform
Maciej Reichel - One of the best experts on this subject based on the ideXlab platform.
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full scale measurements of pressure field induced on the quay wall by Bow Thrusters indirect method for seabed velocities monitoring
Ocean Engineering, 2018Co-Authors: Teresa Abramowiczgerigk, Zbigniew Burciu, Wojciech Gorski, Maciej ReichelAbstract:Abstract The paper presents the results of full-scale experimental investigation of loads generated on the quay wall by Bow Thrusters during unberthing of a self-manoeuvring vessel. The presented research allowed for the comparison of the measurements results with generally accepted empirical prediction methods and confirmed the utility of the developed measuring setup for the on-line monitoring of jet induced loads. The conclusions from the research are focused on the strengths and limitations of the presented measuring method and its applicability for the on-line monitoring of loads induced by Bow Thrusters on seabed protection along the quay wall.
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Full scale measurements of pressure field induced on the quay wall by Bow Thrusters – indirect method for seabed velocities monitoring
Ocean Engineering, 2018Co-Authors: Teresa Abramowicz-gerigk, Zbigniew Burciu, Wojciech Gorski, Maciej ReichelAbstract:Abstract The paper presents the results of full-scale experimental investigation of loads generated on the quay wall by Bow Thrusters during unberthing of a self-manoeuvring vessel. The presented research allowed for the comparison of the measurements results with generally accepted empirical prediction methods and confirmed the utility of the developed measuring setup for the on-line monitoring of jet induced loads. The conclusions from the research are focused on the strengths and limitations of the presented measuring method and its applicability for the on-line monitoring of loads induced by Bow Thrusters on seabed protection along the quay wall.
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Longitudinal Motion Due to Action of Tunnel Thrusters
Polish Maritime Research, 2018Co-Authors: Maciej ReichelAbstract:Abstract Tunnel Thrusters are propulsion and active control devises that provide a side force, or transverse thrust, to support mooring operations or position keeping. They shorten the time of manoeuvring, reduce the cost of towage and since inception, manoeuvrability specifically in ports has become a lot easier. Tunnel Thrusters can either be operated manually or with the help of Dynamic Positioning systems which makes it even more efficient. Theoretically, the transverse force due to tunnel thruster action should generate only lateral and rotational motion. Therefore, it is typical and a common practice during manoeuvring simulations that the longitudinal motion due to the action of tunnel Thrusters is neglected. Nevertheless, the experience of masters and pilots shows that some longitudinal motion due to the action of tunnel Thrusters appears. This paper shows some examples of turning manoeuvres carried out with Bow Thrusters only, i.e. no additional control devices or tug assistance have been used. The manoeuvres have been carried with minimal possible initial longitudinal nor lateral speed. Model tests have been done with the use of large manned models of VLCS, PCTC and LNG carrier, which differ in hull shape, dimensions and shape coefficients. Results obtained from the tests confirm that the motion caused by Bow thruster besides rotational and lateral motion consists additionally of longitudinal motion. Analysis of the combination of motions due to the action of tunnel Thrusters have been done and some rationale for this phenomenon has been presented. Additionally a short analysis of position of pivot point during tunnel thruster test has been carried out.
Teresa Abramowicz-gerigk - One of the best experts on this subject based on the ideXlab platform.
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Full scale measurements of pressure field induced on the quay wall by Bow Thrusters – indirect method for seabed velocities monitoring
Ocean Engineering, 2018Co-Authors: Teresa Abramowicz-gerigk, Zbigniew Burciu, Wojciech Gorski, Maciej ReichelAbstract:Abstract The paper presents the results of full-scale experimental investigation of loads generated on the quay wall by Bow Thrusters during unberthing of a self-manoeuvring vessel. The presented research allowed for the comparison of the measurements results with generally accepted empirical prediction methods and confirmed the utility of the developed measuring setup for the on-line monitoring of jet induced loads. The conclusions from the research are focused on the strengths and limitations of the presented measuring method and its applicability for the on-line monitoring of loads induced by Bow Thrusters on seabed protection along the quay wall.
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Experimental study on the hydrodynamic forces induced by a twin-propeller ferry during berthing
Ocean Engineering, 2008Co-Authors: Teresa Abramowicz-gerigkAbstract:Abstract The paper presents the experimental study on the influence of wall effect on the hydrodynamic forces induced by the propellers and Thrusters of a ferry during the berthing. The program of the model tests was developed for the twin-propeller, twin-rudder, man-manned model of a car–passenger ferry in 1:16 scale, equipped with two Bow Thrusters. The different combinations of the operational settings of Bow Thrusters and propellers operating in the push–pull mode allowed to observe and quantify the variation of the hydrodynamic forces due to the changes of the water depth to draft ratios and distances to the quay. The results of model tests are introduced and discussed in the paper. The difference between the measured total hydrodynamic force and superposition of the component forces induced by the propellers and Thrusters has been investigated. According to the structure of the generally accepted modular manoeuvring model, the proposition of the weight factors for the component forces comprising the interaction effects has been introduced and discussed.
Ehab Tolba - One of the best experts on this subject based on the ideXlab platform.
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minimizing bed scour induced by ship Bow Thrusters by using quay wall flow deflector
Malaysian Journal of Civil Engineering, 2019Co-Authors: Elsayed M Galal, Nezar S Halabia, Ehab TolbaAbstract:Recently, the combination of larger Bow-Thrusters installed with vessels have created higher levels of bed scour action affecting the berthing structure and its overall stability. Therefore, the bed near a quay wall structure must have sufficient strength by placing a bed protection which may cause the cost of the project to rise. This research is carried out to investigate experimentally the effect of modifying the geometry of the quay wall surface on minimizing bed scour. This is done by inserting flow deflectors within the longitudinal direction of the wall surface in order to deflect/minimize the water jet affecting the bed near the quay wall. Experimental tests had been carried out for single and triple deflectors. The results showed that the use of flow deflectors achieved a reduction in bed eroded area in front of quay wall face by about 63%, and causes the start point of erosion to move far away from it; this may improve the stability of quay walls. Therefore, the importance of the present study is testing a new possible measure to improve the stability of quay walls by minimizing the scour in front of the wall and to decrease the cost of bottom protection.
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the effect of sea side quay wall roughness and inclination on bed scour induced by ship Bow Thrusters
Malaysian Journal of Civil Engineering, 2016Co-Authors: Elsayed M Galal, Nezar S Halabia, Ehab TolbaAbstract:In order to increase their transport efficiency, modern ships are built with increasingly larger propellers and Bow-Thrusters. The combination of larger propellers with greater power and a reduction in bed clearance has created higher levels of bed scour action affecting berthing structures. Therefore, propeller-induced scours need to be considered in the design of quay wall structures. In this study, an experimental investigation was carried out to examine the effect of sea side wall roughness and wall inclination angle on the scouring action induced by Bowthruster in front of the quay wall. Two different kinds of sea side quay wall surfaces (glass and concrete) as an indicator of wall roughness and four different sea side wall inclination angles ( = 90, 75, 60, and 45) were considered in this study. The results showed that the eroded area has been decreased with the increase of the sea side wall roughness and inclination
D.a. Taylor - One of the best experts on this subject based on the ideXlab platform.
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Chapter 10 – Deck machinery and hull equipment
Introduction to Marine Engineering, 1996Co-Authors: D.a. TaylorAbstract:Publisher Summary This chapter discusses the various deck machinery used by a ship and several hull equipment found inside the machinery space. These include deck machinery such as mooring equipment, anchor handling equipment, cargo handling equipment, and hatch covers. Other items include lifeboats and liferafts, emergency equipment, watertight doors, stabilizers, and Bow Thrusters. The operations of mooring, cargo handling, and anchor handling all involve controlled pulls or lifts using chain cables, wire, or hemp ropes. The drive force and control arrangements adopted will influence the operations. Several methods are currently in use, and these are examined in this chapter. And then it considers the associated equipment. Three forms of power are currently in use: steam, hydraulic, and electric. The chapter describes each one of them together with its advantages and disadvantages for particular duties or locations. Finally, the last section of the chapter explores the different kinds of safety equipments. These are emergency equipment for power generation and pumping, survival equipment such as lifeboats and liferafts, and the sound signal equipment in the form of the whistle.
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Deck machinery and hull equipment
Introduction to Marine Engineering, 1990Co-Authors: D.a. TaylorAbstract:This chapter discusses the various deck machinery used by a ship and several hull equipment found inside the machinery space. These include deck machinery such as mooring equipment, anchor handling equipment, cargo handling equipment, and hatch covers. Other items include lifeboats and liferafts, emergency equipment, watertight doors, stabilizers, and Bow Thrusters. The operations of mooring, cargo handling, and anchor handling all involve controlled pulls or lifts using chain cables, wire, or hemp ropes. The drive force and control arrangements adopted will influence the operations. Several methods are currently in use, and these are examined in this chapter. And then it considers the associated equipment. Three forms of power are currently in use: steam, hydraulic, and electric. The chapter describes each one of them together with its advantages and disadvantages for particular duties or locations. Finally, the last section of the chapter explores the different kinds of safety equipments. These are emergency equipment for power generation and pumping, survival equipment such as lifeboats and liferafts, and the sound signal equipment in the form of the whistle.
H D Mcgeorge - One of the best experts on this subject based on the ideXlab platform.
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10 – Bow Thrusters, stabilizers and stabilizing systems
Marine Auxiliary Machinery, 1999Co-Authors: H D McgeorgeAbstract:The transverse thruster, installed in the Bow has become an essential item of equipment on many vessels. It enables the normal process of docking to be managed without tug assistance because the vessel is made more maneuverable at low speeds. Safety is increased when berthing in adverse weather conditions, provided that the required thruster capacity has been correctly estimated. Transverse Thrusters are installed to facilitate the positioning of some types of workboats. Thrust calculations must be based on the abovewater profile of a ship as well as the underwater area. Bow thrust compartments below the waterline should be checked frequently for water accumulation and pumped out as necessary to keep them dry. The stabilizing power of fins is generated by their movement through the sea and lift’ created by the flow of water above and below the ‘aerofoil’ or hydrofoil shape. Thus, active fin stabilizers are fitted to faster types of ship, operating at perhaps 15 or more knots. Activated fin stabilizers which extend and stow athwart ships, require spaces for fin boxes and guide bars of a length more than twice that of the fins, within the ship. Tank stabilizers are virtually independent from the forward speed of the vessel.
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10 Bow Thrusters stabilizers and stabilizing systems
Marine Auxiliary Machinery (Seventh Edition), 1999Co-Authors: H D McgeorgeAbstract:The transverse thruster, installed in the Bow has become an essential item of equipment on many vessels. It enables the normal process of docking to be managed without tug assistance because the vessel is made more maneuverable at low speeds. Safety is increased when berthing in adverse weather conditions, provided that the required thruster capacity has been correctly estimated. Transverse Thrusters are installed to facilitate the positioning of some types of workboats. Thrust calculations must be based on the abovewater profile of a ship as well as the underwater area. Bow thrust compartments below the waterline should be checked frequently for water accumulation and pumped out as necessary to keep them dry. The stabilizing power of fins is generated by their movement through the sea and lift’ created by the flow of water above and below the ‘aerofoil’ or hydrofoil shape. Thus, active fin stabilizers are fitted to faster types of ship, operating at perhaps 15 or more knots. Activated fin stabilizers which extend and stow athwart ships, require spaces for fin boxes and guide bars of a length more than twice that of the fins, within the ship. Tank stabilizers are virtually independent from the forward speed of the vessel.
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7 – Auxiliary power
Marine Auxiliary Machinery, 1995Co-Authors: H D McgeorgeAbstract:Publisher Summary Auxiliary medium-or high-speed diesel engines are mainly used as the prime movers for generators, but they may also be coupled to provide a direct drive for large pumps, Bow Thrusters, or other machinery. Diesel-driven generators can be expensive in terms of fuel cost and maintenance requirements. A better economy in the provision of electrical power is achieved with the use of a generator, which can be operated at sea, and on power derived from the main propulsion system. The quest for electrical power from the ever-decreasing quantity of exhaust gas energy has fostered progress in the area of harnessing the otherwise wasted heat energy. Power turbines, driven by exhaust gases from engines, are used to convert waste heat energy into mechanical energy, which is delivered to the main propulsion system through a fluid coupling. They are used to provide an integrated drive as well, with diesel for generators.