Different Types Of Ships Research Articles

Measures for noise reduction aboard ships in times of increasing comfort demands and new regulations

Through the revision of the “Code of Noise Levels on Board Ships,” the International Maritime Organization has tightened its recommendations from 1984 by lowering the allowed maximum noise exposure levels on board ships. Hereby, the most significant change can be observed for cabins. To consider the effects of noise on health and comfort their noise level limits were reduced by 5 dB to 55 dB(A) equivalent continuous SPL. Another important alteration is that parts of the new code will be integrated into the SOLAS-Convention, and therefore, some of its standards will become mandatory worldwide. In order to meet the increasing demands, the focus has to be put on noise reduction measures in receiving rooms and along the sound propagation paths since the opportunity to use noise reduced devices or machines is not always given. This study gives an overview of the current noise situation on board of different types of ships. The efficiency of measures for noise reduction is discussed with focus on cabins and cabin-like receiving rooms. Especially, the role of airborne sound radiation from ship windows induced by structure-borne sound is investigated.

Alternative Teaching Methodology in Marine Engineering Courses: employing TIC & CFD Tools

An alternative teaching-learning methodology for the subject "Hydrodynamic, Resistance and Propulsion" in Degrees concerned with NAval Engineering, is presented. The goal of the pedagogical approach is the acquirement of appropiate skills related to the ability of analyzing and designing different types of ships. The blended learning concept is employed, including the supervised learnin as key ingredient. The roles of both Information and Communication Technologies (ICT) and Computational Fluid Dynamics (CFD), as educational tuools, are some specific features of the methodology. A pedagocial method that involves project based learning, using CFD, is applied. The evaluation of the student satisfaction is conducted by questionaries.

Improving teaching–learning process through ICT methods assisted with CFD techniques for marine engineering courses

ABSTRACTThis article presents a teaching–learning methodology for the subject “Hydrodynamic, Resistance and Propulsion” in the Degree of Naval Architecture. A new teaching approach is proposed, for ensuring that students acquire skills related to the ability of analyzing and designing different types of ships. The roles of both Information and Communication Technologies (ICT) and Computational Fluid Dynamics (CFD) methods are some specific features of the methodology. © 2013 Wiley Periodicals, Inc. Comput Appl Eng Educ 23:239–249, 2015; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21592

Effect of Pretension on Moored Ship Response

Moonpools are vertical wells in a floating body used onboard many types of vessels like Exploration and drilling vessels, Production barges, Cable-laying vessels, Rock dumping vessels, Research and offshore support vessels. Moonpool gives passage to underwater activities for different types of ships as per their mission requirements. It is observed that inside a moonpool considerable relative motions may occur, depending on shape, depth of the moonpool and on the frequency range of the waves to which the ship is exposed. The vessel responses are entirely different in zero and non-zero Froude number. Former situation is paid attention in this study as the mission requirement of the platform is to be in the particular location for long period of operation. It is well known that there are two modes of responses depending on the shape of the moonpool viz., piston mode for square shape and sloshing mode for rectangular shapes with different aspect ratios of opening like 1:1.5 and 1:2 ratios. Circular shaped moonpool is also tested for measuring the responses. The vessel moored using heavy lines are modelled and tested in the wave basin. The pretensions of the lines are varied by altering the touchdown points and the dynamic tensions on the lines are measured. The different modes of oscillations of water column are measured using wave gauge and the vessel response at a particular situation is determined. RAOs calculated for various situations provide better insight to the designer.

Model tests on the moored vessel with different moonpool shapes

Moonpools are vertical wells in a floating body used onboard many types of vessels like cable-laying vessels and offshore support vessels. Moonpool gives passage to underwater activities for different types of ships as per their mission requirements. It is observed that inside a moonpool considerable relative motions may occur, depending on shape, depth of the moonpool and on the frequency range of the waves to which the ship is exposed. The vessel responses are entirely different in zero and non-zero Froude number. Former situation is paid attention in this study as the mission requirement of the platform is to be in the particular location for long period of operation. It is well known that there are two modes of responses depending on the shape of the moonpool viz., piston mode for square shape and sloshing mode for rectangular shapes with different aspect ratios of opening like 1:1.5 and 1:2 ratios. Circular shaped moonpool is also tested for measuring the responses. The vessel moored using heavy lines are modeled and tested in the wave basin. The moored lines are provided with pre-tension and the dynamic tensions on the lines are measured. The different modes of oscillations of water column are measured using wave gauge and the vessel response at a particular situation is determined. RAOs determined for various situations provide better insight to the designer. The experiments done in the wave basin may also be compared with a software package meant for handling moored floating bodies.

ICONE19-43821 NUCLEAR POWERED SHIPS : Findings from A FEASIBILITY STUDY

Nuclear shipping is attractive for several reasons, one of which is its positive effect on emissions (CO_2, NOx and SOx). The benefits, however, do not come without risks of possible harmful effects on humans and wildlife. Nuclear ships set themselves apart from conventional ships, as well as from on-shore nuclear power-plants, on several counts. 1) The reactor-unit are non-stationary, and the reactor is subject to the ship motions. 2) Ship reactors must be compact due to space constraints. 3) Special design considerations are required to ensure reactor safety and security, as well as to enable refuelling. 4) A naval nuclear fuel cycle infrastructure for fuel fabrication, handling, and disposal is needed. Technological feasibility of nuclear shipping is by itself inconclusive to a expansion into civilian applications and use. Civilian nuclear propulsion needs to be commercially viable and politically acceptable. Appropriate legislation must be in place, and nuclear shipping concepts with proven safety records and highest possible nuclear proliferation-resistance must be established. Possible "showstoppers" to a viable nuclear civilian shipping industry are outlined in the paper in view of Political, Technical, Regulatory, Commercial, Safety and Security aspects. Further, different types of ships with different propulsion system are compared in lights of life cycle cost and air emission.

Modeling and Simulation of Environmental Disturbances for Six degrees of Freedom Ocean Surface Vehicle

In this paper we focused on Modeling and Simulation of environmental disturbances for ocean Surface Vehicle. We developed ship simulation system for simulating ship motion in a virtual environment with respect to environment disturbances such as sea wave, wind and sea currents. This system simulates ship motions in six degrees of freedom, pitch, heave, roll, surge, sway, and yaw. This system is simple and responds in real-time to interactions and it is based on a mathematical ship model. The mathematical ship model is derived from the non-linear speed equations, Newton’s laws, fluid dynamics and other basic physics. We use multivariable functions to model the ocean surface with superposition of sinusoid functions and the ship model requires fewer amounts of ship data and the mathematical ship model can be used with different types of ships and it can be used in real time virtual reality applications. DOI: http://dx.doi.org/10.4038/sljp.v10i0.3834 Sri Lanka Journal of Physics, Vol. 10 (2009) 39-57

Recommendations for autonomous underway pCO2 measuring systems and data-reduction routines

In order to facilitate the collection of high quality and uniform surface water pCO2 data, an underway pCO2 instrument has been designed based on community input and is now commercially available. Along with instrumentation, agreements were reached on data reduction and quality control that can be easily applied to data from these systems by using custom-made freeware. This new automated underway pCO2 measuring system is designed to be accurate to within 0.1 μatm for atmospheric pCO2 measurements and to within 2 μatm for seawater pCO2, targeted by the scientific community to constrain the regional air–sea CO2 fluxes to 0.2 Pg C year−1. The procedure to properly reduce the underway pCO2 data and perform the steps necessary for calculation of the fugacity of CO2 from the measurements is described. This system is now widely used by the scientific community on many different types of ships. Combined with the recommended data-reduction procedures, it will facilitate producing data sets that will significantly decrease the uncertainty currently present in estimates of air–sea CO2 fluxes.

Decision making and strategies in an interaction situation: Collision avoidance at sea

This paper aims at analysing decisions which are actually made by watch officers onboard ferries in the Dover Strait. More precisely, it aims at characterizing the generic situations in which several courses of actions are available and identifying the strategy underlying an action choice. Relying on the RPD model of Klein [Klein, G. (1997). The recognitionprimed decision (RPD) model: Looking back, looking forward. In C. E. Zsambok & G. Klein (Eds.), Naturalistic decision making (pp. 285–292). Mahwah: Lawrence Erlbaum Associates], it points out the critical cues, the goals of actors and the rules they use. Two sets of data were processed: motions of vessels observed from the vessel traffic system and verbal protocols recorded onboard a ferry with three watch officers. Logistic regression models show that different types of ships do not act in the same way: the slowest vessels tend to keep their course and speed, even if they have to move. The faster cargo ships such as ferries alter their course in compliance with the regulations. In some situations, a ferry may nevertheless follow informal rules. Onboard a ‘give way’ ferry, a watch officer may – in some conditions – alter his course to port rather than to starboard to reduce the course alteration and the loss of time. On board the ‘stand on’ vessel, he may perform an action in order to master the situation, even if the rule requires him to keep his course and speed. 2008 Elsevier Ltd. All rights reserved.

Fuzzy sets analysis for ballast water treatment systems: best available control technology

An overview on various ballast water treatment (BWT) technologies aboard different types of ships is presented. These technologies are: (1) Filtration, (2) Cyclonic systems, (3) Heat treatment, (4) Chemical treatment, (5) Ultraviolet radiation, (6) Ultrasound, (7) Electroporation, and (8) Radiolysis. These technologies are proven technologies for BWT in the marine industry. The fuzzy sets methodology is used to perform a comparison among these different Ballast water systems to choose the best available control technology that should be given the highest priority in terms of development and research. The main objective of this paper is to determine the order in which ballast water systems should be given higher priority to be installed to tackle the world wide ballast water pollution problem. These systems are compared according to their benefits and cost. Based on the benefit to cost ratio, the results show that the filtration treatment appears to be the method that will provide the best combination of effective treatment and feasibility. The next two options are the use of ultraviolet and ultrasound. All these three options could be used to produce effective and reliable BWT with minimum cost and optimum benefits in terms of issues related to effectiveness, reliability, global benefits, and safety. The least options are radiolysis and chemical treatment due to their high costs and low safety factors. Also this study tries to clear the way for developing new and existing technology, and to provide a platform for successful treatment solution.

Shipping Patterns in the Malacca and Singapore Straits: An Assessment of the Risks to Different Types of Vessel

��� With the objective of improving the quality of assessments of the threat to shipping in the Malacca and Singapore Straits, this article provides an appreciation of the pattern of shipping traffic and of the types of vessel using the Straits. It is based on the notion that statements about the number of ships passing through the Straits on a per day, per month or per year basis obscure more important assessments about the relative vulnerability of different types of ship. Consideration must be given to the types of vessel, their routes and location. The paper distinguishes between through traffic transiting between the Pacific and Indian Ocean; local traffic operating between ports littoral or adjacent to the Straits; and other vessels, notably fishing vessels, working within the Straits. It identifies the types of vessel using the Straits that are most at risk.

An investigation of hydrodynamic forcing on a semi-planing monohull in following and stern quartering seas

Navigating a ship in following and stern quartering seas is well known to seafarers for the possible troublesome situations that may arise. The issue has also been addressed by many researchers during the last 50 years. In 1964 Du Cane and Goodrich presented one of the first systematic studies on ships in following seas together with a compilation of accounts on real occurrences of dangerous situations for ships in following and stern quartering seas. Later research has confirmed the possibility for occurrence of several types of allegedly capricious behaviour for a ship travelling at a course within one third of the compass card, i.e. between −60° and 60° relative to the waves. The research included in the references is covering many different types of ships from fishing boats to fast naval vessels and merchant ships.

Non-fatal occupational injuries related to slips, trips and falls in seafaring

Merchant seafaring often involves hazardous occupational operations and several studies have shown increased overall injury mortality. The aim of this study was to describe the risks involved in slip, trip and fall (STF) injuries in merchant seafaring, in order to point out areas for prevention. A questionnaire study was carried out in 11 countries with 6,461 participants. The seafarers gave information on whether they were injured during their latest tour of duty, and whether STF preceded the injury. Of the total reported injuries 43% (n=467) were STF related. Fractures and sprains accounted for 42% of the STF injuries compared with 17% for non-STF injuries. The proportions of STF injuries for different types of ships and areas of the ships varied from < 30% to >60%, particularly work on passenger ship decks, where STF injuries were >60%. The proportions of STF injuries increased by age and by severity of the injury. Injuries related to STF on merchant ships were more frequent than previous estimates. There is a need for improvements in defining, reporting, and preventing STF injuries in merchant seafaring.

Bayesian and Neural Networks for Preliminary Ship Design

To ease the determination of the main particulars of a ship at the initial design stage it is convenient to have tools which, given the type of ship and a few other parameters, output estimations of the remaining dimensions. To establish such a tool, a database of the characteristics of about 87 000 ships is acquired and various methods for derivation of empirical relations are employed. A regression analysis is carried out to fit functions to the data. Further, the data are used to learn Bayesian and neural networks to encode the relations between the characteristics. On the basis of examples, the three methods are evaluated in terms of accuracy and limitations of use. For different types of ships, the methods provide information on the relations between length, breadth, height, draft, speed, displacement, block coefficient and loading capacity. Thus, useful tools are available to the designer when he chooses the preliminary main characteristics of a ship.

Proposal Of Using Higher Tensile Steel HTS-40(390 MPa) On Hatch Coamings Of Open-deckShips

The article presents the proposed scope of application of higher tensile steel (HTS), having yield point of 390 MPa, and the involved design and fabrication problems resulting on a structure of open-deck ships hatch coamings. 1 General assumptions as for using HTS-40 steel at building of open-deck ships Due to the growing pressure exerted by Owners in order to improve economic aspect of sea transport, the ship designers have to use higher tensile steels in their ships to a higher and higher degree. The higher tensile steel grades in question are those steel grades that have yield point above 265 MPa, but not exceeding 400 MPa. On the ships built so far in Szczecin Shipyard (Stocznia Szczecinska S.A. SSSA.) mainly steel grades of R,=315 and 355 MPa have been used and all technological problems involved have been overcome. In case of steel grades of 390 MPa, these have never been used so far in SSSA. Higher tensile steel grades are applied in structures of different types of ships for building of high loaded hull structure components characterized by high stress levels, such as strength deck plating and longitudinals, sheer strakes, bottom Transactions on the Built Environment vol 42, © 1999 WIT Press, www.witpress.com, ISSN 1743-3509

電子式スリッピングクラッチの開発

The fishing boat industry has a chronic shortage in the labor force due to bad working conditions. Improvement of the working environment and labor saving by automation are needed.“Electronically Controlled Clutch”was developed to meet the above demands. We have been researching the required performance and function needs based on the mechatronics previously developed at our company, and at the same time, improving our grasp of the market demand by going aboard different types of ships at different locations.In this article, we will introduce the summary of a case study on mechatronics technology as applied to the propeller propulsion system.

Seafaring: a risk for seamen's oral health?

Information about the oral status and dental health behavior and the working history of 369 Finnish seamen on different types of ships was gathered by means of a questionnaire. A control group of workers on shore was formed for sailors 35-44 years of age. Removable dentures were worn by 16% of the seamen. Oral disorders during the week before the study were reported by one-third. During the previous 2 years 14% of the sailors had had at least one episode of oral troubles, 15% twice and 9% three or even more times. One-third of seamen with oral trouble had needed pain-killing tablets or antibiotics. Sick leave days had been needed by 3% of respondents during the previous 2 years because of oral disorder (mean length of sick leave period was 1.4 days). The control group reported gum bleeding more often than the seafarers. Even though there were no signs of poorer dental condition in sailors than in the controls on shore, the possibility that the seafaring could constitute a risk for the oral health of seamen in other age groups cannot be excluded.

A New Interpretation of Linear Theory in the Calculation of Ship’s Wave Resistance

A modification of linear theory is suggested based on the existence of maximum amplitudes and energy density of surface waves. The value of a density is derived from a calculation test for the Wigley ship model and used in the Havelock formula modification. Such an interpretation of linear theory, as shown in the paper for different types of ships, results in a large reduction of discrepancies between the calculation and experimental data.

Estimation of system damping ratios of ship hull-girders in response to random environment

Damping effects, the basic energy-loss mechanisms in practical structures, are seldom fully understood. Consequently it is not usually feasible to determine the damping coefficient by means of the corresponding generalized damping expression. For this reason the damping in most structural systems must be evaluated directly by experimental methods. Especially for a ship structure vibrating in the random ocean, the system damping becomes more complicated. In this report, by application of the stochastic modelling technique on the time series, of which the structural response signals were picked up aboard three different types of ship in sea trials, four statistica; mean curves of damping ratios versus frequencies of the ship hull-girder are presented. The analyst may refer to these curves to choose reasonable values of the frequency-dependent damping ratios in solving his problems of ship structure dynamics.

A Nested Case-Control Study of Disability Pension among Seamen, with Special Reference to Neuropsychiatric Disorders and Exposure to Solvents

A cohort of 1,687 captains and mates from different types of ships were followed for recording of disability pension from 1970 to 1986. 199 cases were found. At date of diagnosis each case was age-matched to 4 randomly selected seamen within the rest of the cohort at risk. A strong relationship between disability pension due to neuropsychiatric diagnoses and work on tankers was found, especially when restricted to work as a mate on the tankers. These mates experience the highest exposure to organic solvents within the investigated group. The findings indicate an occurrence of chronic nervous system disorders due to long-term exposure to organic solvents.