Добірка наукової літератури з теми "Icebreakers (Ships) Design and construction"

An economic and analytical model for evaluating the criteria of efficiency (profitability) of investments in the projects of innovative nuclear icebreakers of the Northern Sea Route is suggested. The model is based on the new analytical representation of the methodology for forecasting the investment project efficiency that is widely used in international practice. The mathematical expression for the net discounted income provides convenient formulas for calculating several investment efficiency criteria for nuclear icebreakers: internal rate of return, minimum annual revenues from icebreaker convoys, discounted payback period, and the volume of delivered cargo. The paper gives estimates of the criteria for the efficiency of investments in “Leader” class icebreakers that depend on the discount rate of cash flows, capital, and operating costs. It is shown that at high capital costs, typical for construction of “Leader” class nuclear icebreakers, the minimum required revenue of an icebreaker, representing a financial burden for ships transporting cargo along the NSR, rapidly increases with the growth of discount rate and the reduction of investment payback period. This means that the profitability of such icebreakers is only possible at low discount rates of 2–3% per year, which is an extremely low-interest credit. Even with low interest and impressive technical characteristics of the icebreaker (high speed of navigation, large number of ships in the caravan and their maximum capacity) the payback period would exceed 25 years.

This paper utilizes available data on existing icebreaking ships to compile a review of the design features that influence ship performance. The data were extracted from a recently completed review of the state of the art of Arctic ship technology and include icebreaking ships from Argentina, Canada, Denmark, Finland, Japan, Sweden, the United Kingdom, the Soviet Union, the United States, and West Germany. It is the aim of this paper to offer guidance in the initial stages of icebreaker design and thereby give confidence to the designer in the selection of dimensions, hull shape and propulsion.

This paper describes the design and construction of two small icebreakers for operation exclusively in the fast-flowing Niagara River above the celebrated falls. Special features of these purpose-built craft—which due to their dangerous operating environment include many redundant systems—are presented. Results of maneuvering trials and model tests are given, along with a comparison between hull forms of the two vessels—Ontario Hydro's Niagara Queen II and the William H. Latham, operated by the New York Power Authority.

Propeller of the shallow-water icebreaker (wide blades, blade area ratio EAR = 0.87) is designed to ensure power efficiency and second step cavitation prevention at bollard pull. Modified sharp profile is applied to reduce ice loads acting on propeller and propulsion complex as well as to ensure main electric engine operability. Based on the updated CNIIMF procedure for structural design of ice-breaking propellers, this study determines global and local ice loads on propeller blades, calculates their stress-strain state and assigns the scantlings for wide-blade propeller so as to ensure fatigue and static strength (including edges and peripheric sections).

Object and purpose of research. This paper discusses structures of high-power electric propulsion systems for ships. The purpose was to give a summary of design solutions made in development of these systems. Materials and methods. This paper relies on academic and technical data, as well on the long-term author’s experience in marine electric propulsion R&Ds. The solution suggested by the author is based on the comparative analysis of design solutions adopted in the development of structures for high-power marine electric power and propulsion systems. Main results. Summary on design solutions for high-power electric propulsion systems of such ships as icebreakers, oil tankers, LNGCs and cruise liners. Conclusion. Results obtained by author were used in the design of the electric propulsion system of the «Lider» nuclear icebreaker and further could be used in design of Arctic vessels.

The main purpose of ice-resistant coatings designed for icebreakers and ice navigation ships is the ability to protect of the ship’s hull in the most severe operating conditions. The special coatings certified by the Classification Societies for ice abrasion can provide this protection. These coatings allow to reduce the required thickness of the ship’s hull and reduce the construction weight of the ships. On the other hand, these coatings must have a low friction coefficient, which reduce the frictional resistance of the hull on ice and fuel consumption, increase the service life of the ship and power plant, reduce CO2 emissions into the atmosphere and affect to the operational and economic efficiency of the ship. In this paper, we present the results of experimental tests of friction coefficient on ice for various types of ice-resistant coatings and analysis the influence of ice-resistant coatings characteristics to the energy efficiency of ice-going ships.

The objective of the work reported here is to ensure that ice-capable ships are both safe and economical. It is largely based on research conducted over the past two decades. The present methodology allows the designer to calculate a bow plating thickness which will resist local ice loads and be cost-effective. Full-scale data for the MV Canmar Kigoriak and USCGC Polar Sea were ranked, curves were fitted through the tail of each data set, and a Type I extreme probability distribution was derived for each data set. The Canmar Kigoriak data were then subdivided based on contact area and a simulation was performed to derive the load distributions on subregions of the instrumented panel, termed subpanels. On the basis of this analysis, a local ice load model was validated and is used in the subsequent analysis. To evaluate the strength of the bow plating, three limit stages (three-hinge collapse, permanent set, and membrane collapse) are considered. Statistical distributions for each of the input parameters are established. The probability of failure is calculated for each limit state corresponding to a range of plate thicknesses, frame spacings, and annual numbers of impacts, using First Order Reliability Method software. Plate thickness is optimized for minimum cost. Minimum safety levels for permanent set and membrane collapse are also specified. The objective function considers costs due to construction, aesthetics, repair, and replacement. An empirical expression for the expected annual cost of damage is developed. Optimum plating thicknesses are specified. Costs associated with lost use of the vessel or increased steel weight can also be specified.

Abstract The rapid improvement of lithium-ion rechargeable battery (LIRB) has given a powerful impetus to the development of environmentally friendly, powerful and universal for use on ships and underwater vehicles. The practice of building electric ships for many years has confirmed the effectiveness of electric propulsion for many types of vessels. Organically, electric propulsion fits into icebreakers and those vessels whose operation is associated with increased maneuvering modes and variable loads on propellers. LIRB has been actively used on ferries operating in a wide range of outdoor temperatures. On diesel-electric submarines (DES), the use of rechargeable batteries is traditional and is the main source of electricity. The subsequent development of new sources of electricity, the improvement of power semiconductor devices and microelectronics has led to the successful implementation of ideas for the construction of fully electric offshore facilities.

A method for selection of parameters of ship propulsion system fitted with compromise screw propeller This paper concerns an algorithmic method for preliminary selection of parameters of ship propulsion system fitted with fixed screw propeller in the case when the ship's operation is associated with significant changes of waterway depth and width, hull resistance of the ship and its service speed. Mathematical model arguments of the considered design problem are main ship design parameters identified in the preliminary design stage. Structure of the formulated model complies with formal requirements for continuous- discrete mathematical optimization problems. The presented examples of application of the method concern an inland waterways ship fitted with compromise screw propeller optimized in the sense of minimization of fuel consumption for passing a given route distance within a given time. The elaborated method may be especially useful in designing such ships as: coasters, inland waterways ships, tugs, pushers, trawlers, mine sweepers, icebreakers etc.

This paper discusses the assignment of this or that ice class as per RS system. The calculations have been prepared to develop a universal tool for comparative metal consumption assessment of ice belts aboard ice-going ships, which might be implemented by determination in terms of the two classifications of ice-going ships and icebreakers of all ship parameters that influence, directly or indirectly, on required metal weight of ice belt structures. This approach is illustrated by a case study: calculation of required ice belt size for a tanker to change her ice class. These results made it possible to judge about metal consumption of ice belt structure and suggest a possible way for its optimization. Additionally, cost effectiveness of hull upgrade was compared for the two variants of ice belt design. The conclusions of this paper underline the necessity of automated calculations for fast assessment of metal consumption and repair costs.

Amphibious ships, configured with floodable well decks, present a unique challenge to the Ship Design Team to incorporate maximum troop, cargo and vehicle capacity, along with sufficient well deck size, to facilitate efficient operation of LCAC (Landing Craft Air Cushion) and other amphibious assault craft in support of power projection operations. Analysis of the various LSD 49 Class alternative designs, revealed significant variance in the stability limits for each design. These variations appeared to be directly attributable to wing wall size, as well as to the geometry of the well deck. In order to better understand the effect of these items, and to develop guidelines for future design efforts, this study concentrated on evaluating the stability limitations for various combinations of beam, well deck configuration, and wing wall size using an LSD 49 Class proposed hull form. The results indicated that the most significant parameter affecting the stability of the LSD 49 Class is the height of the well deck above the baseline. The higher the well deck, the smaller the loss of waterplane inertia caused by the entrance of flooding water into the well deck compartment. For lower well decks, the loss of waterplane inertia is more critical at smaller values of beam, but becomes less critical at the upper values of beam considered. In these cases, off-center wing wall flooding becomes more critical, and it is more advantageous to devote larger percentages of beam to the well deck compartment.
M.S.

Thesis (PhD)--Stellenbosch University, 2002.
ENGLISH ABSTRACT: This work is concerned with the hydrodynamic design of hydrofoil-assisted catamarans. Focus is placed on the development of new and suitable design methods and application of these to identify the most important geometric parameters of catamaran hulls and hydrofoil configurations that influence efficiency and performance. These goals are pursued by firstly gaining a thorough understanding of the governing hydrodynamic principles involved in the design process. This knowledge is then applied to develop new and improved experimental techniques and theoretical methods needed for design. Both are improved to the extent where they can be applied as design tools covering the important semi-displacement and semi-planing speeds, which are the focus of this study. The operational speed range of hydrofoil-assisted catamarans is shown to consist of three distinct hydrodynamic phases (displacement, transition and planing) and that different hydrodynamic principles govern vessel performance in each phase. The hydrodynamics are found to differ substantially from that of conventional high-speed craft, primarily due to the interaction between the hull and the hydrofoils, which is found to vary with speed and results in the need for more complex experimental procedures to be followed if accurate predictions of resistance are to be made. Experimental predictions based on scaled model tests of relatively small hydrofoilassisted catamaran models are found to be less accurate than that achievable for conventional ships because of the inability to correct for all scaling errors encountered during model testing. With larger models scaling errors are encountered to a lesser degree. The most important scale effect is found to be due to the lower Reynolds number of the flow over the scaled foils. The lower Reynolds number results in higher drag and lower lift coefficients for hydrofoils compared with those achieved at full scale. This effect can only be partially corrected for in the scaling procedure using the available theoretical scaling methods. Presently available theoretical methods commonly used for the design of conventional ships were found to be ill adapted for modeling the complex hydrodynamics of hydrofoil-assisted catamarans and required further development. Vortex lattice theory was chosen to model the flow around hydrofoil-assisted catamarans as vortex theory models the flow around lifting surfaces in the most natural way. The commercial code AUTOWING is further developed and generalized to be able to model the complex hull-hydrofoil interactions that change with speed. The method is shown to make good predictions of all hydrodynamic quantities with accuracies at least as good as that achievable through model testing and therefore fulfills the requirements for a suitable theoretical design tool. The developed theoretical and experimental design tools are used to investigate the design of hydrofoils for hydrofoil-assisted catamarans. It is found that the main parameter needing consideration in the hydrofoil design is selection of a suitable hydrofoil lift fraction. A foil lift fraction in the order of 20-30% of the displacement weight is needed if resistance improvements using hydrofoil assistance are to be obtained over the hull without foils. It is often more favorable to use higher foil lift fractions (50%+) as the resistance improvements are better, although careful attention should then be given to directional and pitch-heave instabilities. The Hysuwac hydrofoil system patented by the University of Stellenbosch is found to be hydrodynamically optimal for most hullforms. The hullform and in particular the curvature of the aft buttock lines of the hull are found to have an important influence on the achievable resistance improvements and behaviour of the hydrofoil-assisted hull at speed. Hull curvature is detrimental to hydrodynamic performance as the suction pressures resulting from the flow over the curved hull counter the hydrofoil lift. The hullform best suited to hydrofoil assistance is found to be one with relatively straight lines and hard chine deep- V sections. The main conclusion drawn from this study is that hydrofoil-assistance is indeed suitable for improving the performance and efficiency of catamarans. The design and optimization of such vessels nevertheless requires careful consideration of the various resistance components and hull-foil interactions and in particular, how these change with speed. The evaluation of resistance for design purposes requires some discipline between theoretical analysis and experimental measurements as the complexity of the hydrodynamics reduce the accuracies of both. Consideration of these factors allows hulls and hydrofoils to be designed that are efficient and also free of dynamic instabilities.
AFRIKAANSE OPSOMMING: Hierdie studie is gerig op die hidrodinamiese ontwerp van hidrovleuel-gesteunde katamarans. Daar word gefokus op die ontwikkeling van nuwe en geskikte ontwerpmetodes, asook die toepassing van hierdie metodes om die belangrikste geometriese parameters van katamaranrompe en hidrovleuel-konfigurasies wat 'n invloed op doeltreffendheid en werkverrigting het, te identifiseer. As aanloop tot die studie is 'n deeglike begrip van die onderliggende hidrodinamiese beginsels bekom. Hierdie kennis is toegepas om nuwe en verbeterde eksperimentele en teoretiese tegnieke te ontwikkel wat nodig is vir die ontwerp van hidrovleuel-gesteunde katamarans in die belangrike deels-verplasing en deels-planering spoedbereike. Daar word getoon dat die bedryfspoedbereik van 'n hidrovleuel-gesteunde katamaran uit drie onderskeibare hidrodinamiese fases bestaan, naamlik verplasing, oorgang en planering, en dat verskillende hidrodinamiese beginsels die vaartuig se werkverrigting in elke fase bepaal. Daar is ook gevind dat die hidrodinamika wesentlik verskil van dié van konvensionele hoëspoed-vaartuie, hoofsaaklik as gevolg van die interaksie tussen die romp en die hidrovleuels wat wissel na gelang van die spoed. Hierdie interaksies moet in ag geneem word gedurende die ontwerpproses en beide eksperimentele en teoretiese metodes is nuttig om die omvang daarvan te bepaal. Daar is gevind dat die eksperimentele voorspellings gebaseer op toetse met relatief klein skaalmodelle van hidrovleuelgesteunde katamarans minder akkuraat is as dié wat bereik kan word met konvensionele skepe. Dit is omdat al die skaalfoute wat tydens die toetsing met die model ontstaan, nie gekorrigeer kan word nie. Die belangrikste skaaleffek is as gevolg van die laer Reynoldsgetal van die vloei oor die afgeskaalde vleuels. Groter modele Die laer Reynoldsgetal lei tot hoër sleur- en hefkoëffisiënte in vergelyking met dié vir die volskaal-hidrovleuels. Wanneer die beskikbare teoretiese metodes gebruik word, kan daar slegs gedeeltelik vir hierdie effek in die skaalprosedure gekorrigeer word. Daar is ook vasgestel dat die skaaleffekte op die Reynoldsgetal verminder word wanneer die hidrovleuels baie nabyaan die vrye oppervlakte is. Dit lei daartoe dat eksperimentele voorspellings van werkverrigting meer akkuraat is vir die ontwerpe waar die hidrovleuels nie so diep onder die water is nie. Daar is gevind dat die teoretiese metodes wat tans beskikbaar is en algemeen vir die ontwerp van konvensionele skepe gebruik word nie die komplekse hidrodinamika van hidrovleuel-gesteunde katamarans kan modelleer nie. Die werwelroosterteorie is gekies om die vloei om hidrovleuel-gesteunde katamarans te modelleer aangesien dié teorie die vloei om hefvlakke op die natuurlikste manier weergee. Die kommersiële kode AUTOWING is verder ontwikkel en veralgemeen om ook die komplekse spoed-afhanklike interaksies van die romp en hidrovleuel te kan modelleer. Hierdie metode lewer goeie voorspellings van al die hidrodinamiese maatstawwe met akkuraathede wat ten minste so goed is soos di wat met modeltoetsing bereik word en voldoen daarom aan die vereistes vir 'n geskikte teoretiese ontwerpmetode. Die teoretiese en eksperimentele ontwerpmetode wat ontwikkel is, word gebruik om die ontwerp van hidrovleuels vir hidrovleuel-gesteunde katamarans te ondersoek. Daar is gevind dat die belangrikste parameter wat in die hidrovleuel-ontwerp in ag geneem moet word, die keuse van 'n geskikte hidrovleuelhefverhouding is. Om in rompe met hidrovleuelsteun verbeterings in die weerstand te kry in vergelyking met rompe sonder vleuels, is 'n vleuel-hef-verhouding van 20-30 persent van die verplasingsgewig nodig. Dit is dikwels beter om hoër vleuel-hef-verhoudings (van 50 persent of meer) te gebruik omdat die verbetering in weerstand dan groter is. Daar moet dan egter gewaak word teen rigtings- en hei-hef-onstabiliteite. Daar is gevind dat die Hysuwachidrovleuel- stelsel wat deur die Universiteit van Stellenbosch gepatenteer is, hidrodinamies optimaal is vir die meeste rompvorms. Daar is gevind dat die vorm van die romp en veral die kromming van die lyne gevorm deur vertikale snitte deur die romp (Engels: "aft buttock lines") van die romp 'n belangrike invloed het op die bereikbare weerstandsverbeterings en die gedrag van die hidrovleuel-gesteunde romp wat op spoed is. Die kromming van die romp is nadelig vir die hidrodinamiese werksverrigting aangesien die suigdruk as gevolg van die vloei oor die gekromde romp die hefkrag van die hidrovleuels teenwerk. Die rompvorm wat die geskikste is vir hidrovleuel-ondersteuning is 'n romp met relatiewe reguit lyne en skerp hoekige diep- V seksies. Die belangrikste gevolgtrekking waartoe tydens die studie gekom is, is dat hidrovleuelondersteuning wel geskik is vir die verbetering van die werkverrigting en die doeltreffendheid van katamarans. Die ontwerp en optimering van sodanige vaartuie verg nogtans die noukeurige oorweging van die verskeie weerstandskomponente en rompvleuel- interaksies en veral hoe hierdie interaksies verander met spoed. Die evaluering van die weerstand vir die doeleindes van ontwerp verg dissipline tussen die teoretiese analise en die eksperimentele metings aangesien die kompleksiteit van die hidrodinamika die akkuraatheid van die algemeen-gebruikte teoretiese en eksperimentele metodes vir die hidrodinamiese ontwerp verminder. As hierdie faktore in ag geneem word, kan rompe en hidrovleuels ontwerp word wat doeltreffend is en ook vry is van dinamiese onstabiliteite.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2008.
This study investigates practical passive methods to improve the seakeeping of a Hydrofoil Supported Catamaran (Hysucat). The Hysucat is a hybrid vessel combining hydrofoil efficiency with the stability of catamarans. The seakeeping of the Hysucat was initially investigated experimentally to determine what seakeeping improvements are inherent to the Hysucat design. The results showed that the seakeeping is improved by 5-30%. A passive suspension system for the main hydrofoil of the Hysucat was designed and tested. A concept development strategy was followed for the design of the suspension system as such a system had never been investigated previously. Detailed specifications for the design were developed and concepts that could satisfy the customer and engineering requirements were generated. Numerical simulation models for the Hysucat and the final concepts were derived assuming a simplified 2nd order system to describe the seakeeping dynamics of the demi-hulls. Unknown parameters were determined using parameter estimation techniques. Representative parameter values were calculated from multiple towing tank experiments. Theory describing the motion of a hydrofoil in an orbital velocity wave field was combined with the hull model to simulate the Hysucat as well as the suspension system concepts. The models indicated that the concept where the main hydrofoil was attached to a spring loaded arm, that was free to pivot in response to orbital waves, was the most feasible in damping out vertical transmitted accelerations. Experimental tests indicated that little improvement was achieved with the suspension system at low frequencies. At resonance the suspension system was effective in decreasing the heave of the vessel by up to 27%. The pitch and acceleration response results showed improvements at the higher encounter frequencies of up to 50%. The calm water resistance of the vessel increased by 10% over the Hysucat with rigidly attached hydrofoils; however was still 24% less than the hull without foils.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2006.
This thesis investigates practical methods of modelling and control of the vertical motions of a hydrofoil assisted catamaran, the HYSUCAT. The aim of the control application is to reduce the motions, and consequently the motion sickness of the passengers. First, a potential flowcommercial program, POWERSEA,was used to model the system. This uses 2-D strip methods to model the planing hull-form of the vessel, and the Peter du Cane hydrofoil theory for modelling of the foils. These simulations are compared to experimental towing tank results, with fair agreement at lower speeds, but limited applicability at high speeds. Thus for the control design the agreement was insufficient. As an alternative, a simple coupled 2 degree-of-freedom spring - mass - damper model is proposed, for which the equations of motion are derived. This has 9 unknown parameters; three of these aremeasured directly, two are modelled, and the remaining four were identified using an experimental parameter estimation technique. Representative parameter values were calculated frommultiple experiments for application in the control design. The design of a control system was based on the above model. First, an output-weighted Linear Quadratic Regulator (LQR) was designed to obtain the full state feedback gains. A non-linear ’bang-bang’ control design was then implemented to try and speed up the response of the system. These control strategies, as well as no control, were applied in the towing tank in regular waves, with good results at low and medium frequencies. At the design point, 32% and 65% reductions in rms motions were achieved for pitch and heave, respectively. At high frequencies, though, not much improvement was achieved due to the bandwidth limitation of the control system. The LQR results were better overall (reduced motions) across the frequency range than the bang-bang controller, as well as having a lower added resistance in waves. The control design of the output-weighted LQR was then revised to be based on alternative outputs, as a possible improvement. However, a further two controller designs did not yield any noticeable improvement and were not developed further.

Depuis les années 1980, des épaves de grands navires construits à clin de la fin du Moyen-Age ont été découvertes sur les littoraux des mers septentrionales et occidentales. Elles ont régulièrement suscité individuellement un intérêt de la communauté scientifique en regard de leur architecture, puisque la fin du Moyen-Age correspond historiquement à l’apparition puis à la diffusion et à l’adaptation de la construction navale à franc-bord d’origine méditerranéenne en Europe du Nord et de l’Ouest. Pourtant, la comparaison des différentes épaves entre elles pour étudier les développements de la construction navale à clin de cette période est très récente et généralement rattachée à l’analyse des épaves nouvellement trouvées.Cette thèse étudie l’ensemble des navires de plus de 20 m de long susceptibles, par leur architecture, d’avoir évolué en haute mer sur les routes du commerce lointain. En regard du contexte technique et historique, cette étude est limitée géographiquement aux mers nordiques et chronologiquement au Moyen-Age tardif et au début de la période moderne.Le navire résulte à la fois des technique de construction navale et de la demande de ses commanditaires. Durant la période d’étude envisagée dans la thèse, les marchands, qui sont également les affréteurs, constituent les principaux armateurs avec les gens de mer, marins et capitaines, qui régulièrement sont propriétaires en totalité ou en partie des grands bâtiments.De ce fait, le contexte historique, affectant les activités de commerce et de transport, contribue à expliquer les développements de la construction navale. De plus, l’analyse technique des épaves permet de comprendre comment les charpentiers de marine ont pu répondre à la demande de ces propriétaires. Pour cela, la reconstitution des épaves, comme celle de l’Aber Wrac’h 1(France), est essentielle, car les données relatives à la construction, la conception et la forme des navires fournissent des éléments de comparaison scientifique fiables en regard des typologies chronologiques et régionales et permettent de replacer le navire dans son contexte historique et socio-économique
Since the 1980s, several wrecks of large clinker ships adting from the late Middle Ages were found on the coasts of Northern and Atlantic seas. The scientific community was regularly interested in the architecture of each site as the late Middle Ages historically corresponds to the appearance, dissemination and adaptation of the carvel shipbuilding from the Mediterranean in Northern and Western Europe. Yet the comparison of the different wrecks themselves to study the development of the clinker shipbuilding of this period is recent and usually linked to the analysis of newly found wrecks.This thesis explores all vessels over a length of 20 meters, which were able, according to their architecture, to sail on open seas for long-distance trade. Due to the technical and historical context, this study is limited geographically to the nordic seas and chronologically to the Late Middle Ages and early modern period.The ship results from the shipbuilding technology and the demand of its owners. During the late Middle Ages, the merchant class, which was the principal user, was also the main shipowner with the seafarers, sailors and captains, who regularly owned all or part of large vessels.Therefore, the historical context, affecting trade and transport activities, helps to explain the developments in shipbuilding. Therefore, technical analysis of wrecks allows understanding how the shipwrights and carpenters could meet the demand of those owners. Hence, there construction of the wreck, such as Aber Wrac’h 1 (France), is essential because the data about the building, design and shape of the vessels provide reliable scientific information for comparison in terms of chronological and regional typologies and help to place the ship in its historical, environmental and socio-economic context

Selon l’image reçue des Vikings, ce peuple incarne l'esprit d’une immense solidarité primitive ayant su résister rudement au joug du christianisme et à la domination du Latin en Europe occidentale. Cette image n’est pas sans ses contradictions et, s’il est vrai que l’écriture était encore inconnue en Scandinavie durant les premiers siècles de l’expansion viking, on sait maintenant que le commerce et la colonisation, autant que les célèbres raids, motivèrent l’irruption des peuples scandinaves sur la scène médiévale. Quant aux navires de ces marchands, colonisateurs, pêcheurs et guerriers, ils apparaissent, un peu à l’image des Vikings eux-mêmes, sur le grand tableau de l’histoire nautique sous l’enseigne d’une originalité et d’une technicité sans parallèle. Comment les Vikings construisaient-ils leurs navires, en leur donnant une symétrie, un équilibre et une finesse si achevés? Les premiers ethnologues qui se sont intéressés à cette question ont privilégié les idées issues d'une tradition acquise par des générations de constructeurs, et d'astuces simples pour équilibrer tribord et bâbord. Puis, ils se sont rapidement tournés vers les techniques inhérentes à la construction à clin : utilisation de planches fendues et non sciées et de rivets abondants témoignant d’une sidérurgie acquise depuis peu. Le problème que présentent ces navires, est que leur construction artisanale demeure conforme à l’image reçue des Vikings, mais que leur conception architecturale, réalisée selon des connaissances théoriques très exactes, brise la notion d’une Scandinavie médiévale illettrée et coupée des grands centres du savoir. Ce travail s’intéresse précisément à la conception architecturale des navires scandinaves du VIIIe au XIe siècle pour montrer comment ils s’insèrent dans un haut savoir européen dès leur apparition. Il explore ensuite les liens qui unissent ce savoir théorique aux aspects véritablement originaux des navires vikings, en l’occurrence leur construction à clin et leur homogénéité sur une grande région à travers plus de cinq siècles. Au terme de cette recherche, l'analyse réalisée sur le maître-couple de trois épaves vikings, une épave antique et une épave scandinave pré-viking, a permis de mettre en évidence plusieurs indices de l'utilisation du système de conception géométrique apparaissant pour la première fois dans les traités d'architecture navale de la Renaissance, et ce, sur chacune de ces épaves. Les résultats obtenus démontrent qu'il est possible d'employer un système transversal de conception pour des navires vraisemblablement construits bordé premier et assemblés à clin.
According to the popular image of the Vikings, this people embodied a spirit of immense solidarity that resisted the yoke of Christianity and the dominance of Latin in Western Europe. This image is not without its contradictions, and while it is true that writing was unknown in Scandinavia during the early centuries of the Viking expansion, we now know that trade and colonization, as much as their famous raids, motivated the irruption of the Scandinavian people on the medieval stage. However, there is an important area where the contradictions between the image of the Vikings and archaeological data still remain intact : the Vikings ships. These ships were designed for traders, settlers, fishermen and warriors. Like the Vikings themselves, their ships reflect a genius of unparallelled originality and high performance. How did the Vikings build their ships, conferring them with such impressive symmetry, balance and finesse? The first ethnologists who studied this issue favoured ideal notions of traditions compiled over generations of builders, along with simple tips for balancing portside and starboard. Following this reductive cultural representation, they then quickly turned to the essential elements of clinker built construction: use of split planks and a great number of iron rivets, evidence of a new metallurgy. The problem with these ships is that, while their construction is made using traditional methods fitting to the popular image of the Vikings, their architectural design, deriving from very refined knowledge, contradicts the idea of an illiterate medieval Scandinavia cut off from the main centres of learning. This work focuses on the architectural design of Scandinavian ships from the eighth to the eleventh century, to show their place in high European knowledge. It then seeks to understand the links between the theoretical and practical aspects of Vikings ships : the clinker built construction and a great homogeneity over more than five centuries. Analysis of the master frames of five wrecks – three Viking ships, one Ancient wreck and a pre-Viking Scandinavian vessel – has found positive indicators of the use of geometric design principles that were formerly thought to be original in Renaissance shipbuilding treatises. Each wreck showed signs of the application of these design principles. The results show moreover that it was possible to use a transverse system of hull design for ships that were built shell-first in the clinker style.

Digital Twin (DT) is considered to be the general purpose technology of the 4th industrial revolution, and realizing its engineering application universality is the common endeavor objective of both universities and companies. Based on the theoretical framework and technical route of DT, this paper focuses on its application exploration for new energy ships. Via blending technologies of cloud computing, open source software, the marine control system and characteristics of new energy, authors carry out a feasibility analysis from the shipboard and cloud architecture and implementation plan respectively. A DT of propulsion system is developed, deployed and operated online on a new energy ship (NES). Meanwhile, the DT data is used to correct the calculation deviation of the battery State of Charge (SOC) by the ship’s physical system. The research in this paper will provide a decision-making platform for situations such as safe operation, fault diagnosis, and condition-based maintenance, and also provide an effective solution for future DT system design of new energy ships.

Recent major oil finds in the Russia Arctic region have led to a marked increase in exploration and production activities. Russian Government and Russian oil companies have invested heavily to make year–round export of oil and gas from the Barents and Pechora Seas a reality. Lukoil, in particular, is developing the Varandey terminal. Lukoil has ordered one dedicated icebreaker and one icebreaking standby/supply ship from Keppel Singmarine. The icebreaker is capable of operating independently in the ice conditions. Built to RMRS LL7 notation, its main function is to perform ice channeling for tankers within the terminal area, assist in tanker maneuvering, mooring and loading. The icebreaking standby/supply ship is built for year–round operation within the area of the offshore oil terminal in the Barents and Pechora Seas. Built to RMRS LU7 notation, its main function is to provide limited ice escort services at the terminal area in the event that the icebreaker becomes unavailable. Operating ambient air temperatures are in the range +30°C to – 40°C. Both ships are built to “Clean Design” standards. The paper describes some of the challenges faced by the Builder during the design and construction of the vessels.

The largest icebreaking tanker built so far, Vasily Dinkov was delivered by Samsung Heavy Industries shipyard to Russian ship-owner SOVCOMFLOT. The vessel was designed and built for the transport of crude oil from the Varandey offshore terminal in east-southern part of the Barents Sea to a transshipment location near Murmansk. The vessel is under long-term charter for NARYANMARNEFTEGAS (NMNG), a joint venture of LUKOIL and ConocoPhillips. The new ship was constructed strictly to the requirements, specification, and concept design provided by the charterer as a basis for final design, building contract, and time-charter agreement. That approach was driven by time constrain, challenges of the project, and uncertainty about experienced icebreaker builder shipyard availability. The ConocoPhillips-LUKOIL marine technical group led the efforts for the feasibility design study at the early vessel design stage and contributed arctic design expertise and oversight of the final design and construction.

Some of the world’s largest recent hydrocarbon discoveries are located beneath the waters of the Northern Caspian Sea, or offshore Kazakhstan. The Kashagan field alone is believed to contain in excess of 10 billion barrels of oil, and there are fields at containing billions of barrels at several other locations. The exploitation of these reserves is now moving from discovery and exploration phases towards production. The Northern Caspian Sea is an unusual environment for offshore development. The water is generally extremely shallow; less than 10 m water depth in almost all locations and down to 1.5 m in several areas above the oil and gas reservoirs. While the Caspian has minimal tides, storm surges can lead to rapid depth changes of over 1 m in depth, up or down. For 3-5 months of the year, depending on location and on the severity of the winter, ice cover is present. Some of the ice is land fast, and the rest is more or less mobile. Large ridge and rubble fields build up, often becoming grounded. Two other challenges for operations are that the environment is sensitive, with important and endangered species. The oil is also associated with high concentrations of sour gas, whose high toxicity presents additional safety risks in the event of blowouts or other accidents. All the drilling and production platforms in the area are and will be gravity based. They range in (planned) size from several square kilometers with over 1000 persons on board to small wellhead installations that will normally be unmanned. The platforms must be supplied and supported by a large fleet of vessels including OSVs, tugs, barges, and other specialized vessels. The flagship of this fleet are the icebreaking supply vessels. This paper describes the genesis, design, construction, and entry into service of the largest of the vessels now in operation, the Ice Breaking Supply Vessel (IBSV) Tulpar, the Kazakh flying horse. BMT SHIP DESIGN Limited was approached in April 2001 by BUE to ascertain whether it was possible to design a shallow water icebreaker with a large deadweight capability and also meet with the requirements of transiting the canal system into the Caspian Sea. The vessel was to be delivered into the Caspian by November 2002 in time for the winter ice season. After exploratory discussions with BUE, BMTSD entered into an agreement to jointly support each other in the development of a suitable vessel design, later to be designated SWIMSS, (Shallow Water Ice Management Standby Supply) and then present this design to AGIP as a viable solution to their requirements. The design was to be based upon design study information supplied by BMT Fleet Technology Limited and was a development of a river icebreaker concept. Agip KCO’s program for the design, build and delivery of the vessel in what was effectively a fourteen-month timeframe was ambitious to say the least at the outset, it was further complicated by the requirements changing twice in the design phase and the contact award being correspondingly delayed. How these challenges were met is set out below.

One of the challenges related to the design of arctic cargo ships is that their transport capacity is dependent on a number of arctic specific design parameters (e.g., ice conditions and the availability of icebreaker support) in which there typically is a significant level of uncertainty and stochasticity. This paper addresses that challenge by presenting a design method that deals with the parameter uncertainty by integrating method of risk assessment in to the design process, i.e., by utilising the principles of Risk-Based Design (RBD). In order to obtain a holistic approach, the design method treats a ship as an arctic sea transport system that might include multiple ships, icebreakers, and port-based facilities such as cargo storages. Using the method it is possible to design an arctic sea transport system that provides a desired level of operational reliability. This provides the means to minimise costs and financial losses due to over- or undercapacity, and thereby to improve the resource-efficiency of the system as a whole.

The U.S. Coast Guard (USCG) operates two Polar Class Icebreakers, the POLAR SEA and POLAR STAR. They have a length of 399 feet and a displacement of 13,500 tons, and are also the most powerful nonnuclear icebreakers in the world, with a maximum rating of 3 x 20,000 shaft horsepower. Each propeller shaft is supported by two water lubricated sterntube bearings. The bearings are a dove-tail slot stave design. Both the aft and forward bearing materials are Thordon XL (Polymer Alloy). The bearing housings are supported by five lands that are integral with the stern bossing. The severe operating environment has caused erosion to the lands due to fretting and corrosion resulting in insufficient support of the bearing housing. Because of concerns about welding on the large HY-80 casting previous efforts to restore fit of the bearing housings has relied on build up of the lands with Belzona Super Metal (a machinable grade metallic polymer). For this application the lands have been repeatedly undercut and boring undertaken to restore fit. Using this method of repair has proven to be short lived and expensive to maintain. A project was undertaken to develop a permanent repair and/or redesign that would effectively address the loss of fit as well as provide for a reliable bearing. The bearing design arrangement was examined, with particular attention to considerations for ice-class service. The properties of potential chocking and bearing materials were assessed. Modifications to the bossing and bearing length were also examined. This paper presents the results of the study.

The future development of oil and gas reserves in remote Polar Regions areas will require a new generation of highly ice-capable vessels. Many may need to be capable of operating at all times of the year. These ships will need to be able to travel faster in heavy ice than all but the largest icebreakers, which poses challenges for both hull and machinery design. The American Bureau of Shipping (ABS), BMT Fleet Technology Limited (BMT) and Hyundai Heavy Industries (HHI) are currently undertaking a joint project aimed at addressing these design challenges. Because of the unique and innovative aspects of large fast ships for Polar ice development, new methodologies for direct calculation of loads on all areas of the hull are needed. The project is also addressing the need for new techniques for the analysis of the outer hull, double hull and gas containment systems of these ships under design and accidental loads; areas in which ‘rule design’ can only provide a starting point. This paper focuses on the midbody ice loads that may results from both ice pressures and from glancing collisions in the midbody area. The paper highlights some of the challenges of direct design.