Academic literature on the topic 'Icebreakers (Ships) Testing'

Abstract 150 years ago, the first modern icebreaker in the world was designed by the naval architect Carl Ferdinand Steinhaus and built for purpose of removing ice barriers on the river Elbe in Hamburg, Germany. No model tests were performed at that time. Later, in the first half of the 20th century, “model tests” for ships were carried out in natural ice on lakes. In the 1950th the first-generation ice model basins were put in operation and ice model testing became a standard method in the icebreaker design process. This paper discusses the influence of the economic and environmental development in arctic regions, driven by shipping and offshore activities in environmental changing Arctic Waters, on the ice model basin design, equipment and testing methods. The developments will be presented with examples from The Hamburg Ship Model Basin (HSVA). To complete the overview, an outlook to future trends is attempted.

Thesis (MEng) -- Stellenbosch University, 2014.
ENGLISH ABSTRACT: A continuous comfort analysis of the whole-body vibration level aboard the S.A. Agulhas II during the 2013-2014 Antarctic voyage was conducted ac- cording BS ISO 2631-1:1997, assuming a standing posture. Just noticeable difference in magnitude testing was conducted on nine subject in the standing posture on a man-rated shaker in the laboratory environment. Two stimuli, a 5 Hz sinusoidal stimulus with a magnitude of 0,5 m.s-2 and a slamming event recoded during the voyage with a magnitude of 0,2 m.s-2 where selected as the stimuli on which to investigate the just noticeable difference thresh-old. The study shows that the vibration level for the duration of the voyage can be considered to be not uncomfortable. The results of the just notice-able difference threshold obtained for the sinusoidal stimulus concur with that found in literature for seated subjects. The just noticeable difference threshold obtained for the ship stimulus does not correlate with the results for the sinu-soidal vibration, implying that there may be an error in the vertical weighting filter provided by the standard or that Webers law does not hold for the just noticeable difference threshold of standing subjects.
AFRIKAANSE OPSOMMING: 'n Deurloopnede gemakanalise van volliggaam vibrasievlakke aanboord die S.A. Agulhas II is uitgevoer. Die analise tydens die 2013-2014 Antarktiese reis is gedoen volgens BS ISO 2631-1 : 1997 vir 'n staande postuur. 'n Net-opmerkbare-verskildrempel toets is uitgevoer op nege vrywillers in 'n staande postuur deur vibrasieherkonstruksie op 'n platform in die laboratorium. Twee stumuli, 'n 5 Hz sinusvorminge stimulus (0,5 m.s-2 r.m.s.) en 'n branderim-pak stimulus (wat tydens die reis opgeneem is, 0,2 m.s-2 r.m.s. is gebruik) om die net-opmerkbare-verskildrempel to ondersoek. Die studie toon dat die vibrasievlakke gedeurende die reis as `nie ongemaklik' geklassifiseer kan word. Die resulte van die net-opmerkbare-verskildrempel verkry vir die sinusvormige stimulus stem saam met bevindinge vir sittende vrywilligers uit die literatuur. Die net-opmerkbare-verskildrempel verkry vir die skip stimulus stem egter nie 'n moonlike onakkuraatheid weegfunksie is wat deur die standard is aanbeveel word of datWeber se wet nie toepaslik is vir die net-opmerkbare-verskildrempel van staande vreywilligers nie.

Ore carriers navigating through ice filled channels and icebreakers escorting cargo ships are two examples of ships which must manoeuvre in ice. Information about the manoeuvring ability of such ships is required for ship design, for voyage planning, and for personnel training. With numerical simulation the eventual goal, physical model tests are an essential step in determining ship manoeuvring equations and parameters. Simulation of ship manoeuvers in ice must take into account dynamics which are qualitatively different from those which control motions in open water. The constraining ice forces may be an order of magnitude larger than the corresponding hydrodynamic forces, and in fact are usually the limiting factors for ship operations in ice. The usual Fourier methods used to determine hydrodynamic coefficients from open water PMM tests are not appropriate for ice manoeuvering analysis, for several reasons. The form of the manoeuvering equations in ice is different from that in open water. Runs in the ice tank are restricted in length, and the number of runs is restricted by the time and cost to produce an ice sheet. This paper outlines a new methodology for manouvering testing and analysis which takes into account both the complexity of the ship-ice interaction and also the requirement to obtain information in a cost-effective manner.

Periodical ice loads on blades of the screw propeller of icebreakers and ice-going ships are one of the reasons for occurrence of fatigue damages of the propulsion system structures as well as for generation of the ship hull vibration. The paper describes an approach of the Krylov Shipbuilding Research Institute, St. Petersburg, to the problem of determination the oscillation of propeller thrust and torque during interaction with ice, and spectra of these loads. A comprehensive approach to this problem includes three lines of investigations, namely, an application of a theoretical model and two types of model tests that are to be performed in the Ice Basin: tests of ice milling by screw propeller model with use of a free-water unit and towing testing of a ship model with working propulsion devices. Each of the investigations lines has its limited capacity and, at the same time, supplements general picture of the complicated process under consideration. The estimated values of periodical ice loads on the propeller may be applied to fatigue strength analysis of structures of the propulsion system or to numerical estimation of vibration characteristics of ice going ship. An example of such calculation of vibration characteristics is shown in the paper. It has indicated that the general ship hull vibration in specified ice conditions can be 3-4 times greater, if ice induced periodical loads on the propellers are taken into account. Periodical ice loads on blades of the screw propeller of icebreakers and ice-going ships are one of the reasons for occurrence of fatigue damages of the propulsion system structures as well as for generation of the ship hull vibration. The paper describes an approach of the Krylov Shipbuilding Research Institute, St. Petersburg, to the problem of determination the oscillation of propeller thrust and torque during interaction with ice, and spectra of these loads. A comprehensive approach to this problem includes three lines of investigations, namely, an application of a theoretical model and two types of model tests that are to be performed in the Ice Basin: tests of ice milling by screw propeller model with use of a free-water unit and towing testing of a ship model with working propulsion devices. Each of the investigations lines has its limited capacity and, at the same time, supplements general picture of the complicated process under consideration. The estimated values of periodical ice loads on the propeller may be applied to fatigue strength analysis of structures of the propulsion system or to numerical estimation of vibration characteristics of icegoing ship. An example of such calculation of vibration characteristics is shown in the paper. It has indicated that the general ship hull vibration in specified ice conditions can be 3-4 times greater, if ice induced periodical loads on the propellers are taken into account.

The United States Coast Guard (USCG) is currently in the detail design phase of the PC2, multi-mission Polar Security Cutter (PSC). This paper discusses ship design factors influencing ice maneuverability considering knowledge gleaned and challenges faced throughout the PSC design process. Capability to perform maneuvers in ice are a function of many design factors which may directly or indirectly influence one another and are integral to the design spiral. Initial designation of design features which strongly affect ice maneuverability begins with a thorough understanding of the Icebreaker’s intended operations, environmental considerations, and design drivers (such as performance areas/requirements) influencing ice maneuverability. The hull form and propulsion system are the most important design features in regard to ice maneuvering capability. Early trade-off analyses and model testing give insight into various design drivers that characterize multi-mission Icebreakers (in contrast to classic Icebreaker designs). Maneuvers of interest include turning in level ice, channel breakouts, and star turns. In operation, ice maneuverability is important to free beset vessels, avoid cumbersome ice formations, and dock at piers. Channel width and edge profile generated by the Icebreaker as well as model testing conservativeness are noteworthy factors to consider for their impact on ice maneuvering.

The next generation ice model testing facility of Aker Arctic Inc. (AARC) was inaugurated in March 2006. The new facility is located in Helsinki at the Vuosaari Marine Business Park, next to the new Helsinki harbour. This facility is the third in the history of Aker Arctic starting in 1969 with Wärtsilä Ice Model Basin (WIMB). Today the new facility has been in operation for two a half years. This period has been still quite a lot of learning and developing practices even the transfer of the ice making happened quite well. The new facility has also opened new possibilities. The paper describes the new facilities and highlights the work done so far. Also among other things the further development possibilities of the AARC FGX model ice is discussed. Making of thick weak ice in the model basin has always been quite a problem. In this respect the enhanced use of AARC FGX ice has given new possibilities in testing. Firstly ice sheets with thickness close to 100 mm were prepared for the new Russian multipurpose icebreaker project to simulate full-scale level ice thickness of 2.85m. Recently model ice with thickness close to 240 mm with flexural strength of 10-20 kPa was manufactured. The paper will discuss also the processes of making these thick/week ice sheets.

In view of the recent announcements by the USA government permitting further drilling in certain areas offshore Alaska and the steady increase in oil prices, it may be again possible to predict that Arctic oil and gas development and transportation projects are imminent. The challenges associated with design and operation of Arctic exploration and production installations are many and have been exhaustively discussed in the past. This paper will summarize these challenges and show how a significant number of them have been addressed in the past and how new technologies may be implemented to alleviate the remaining challenges. In the late seventies and early eighties extensive Arctic R&D work was carried out. A small sample of this work includes the Arctic Pilot Project, the CANMAR icebreaker research program with full scale testing, the Tarsuit artificial island, the Hans island ice load monitoring programs, and the Canadian Coast Guard development of the Canadian Arctic Shipping Pollution Prevention Regulations (CASPPR). The R&D work carried out in Finland and Russia is also discussed. This paper demonstrates how the available results from these projects may be applied in the development of current and new rules and standards. The issues that are still outstanding are highlighted and proposals for possible resolution thereof are made. A presentation of ongoing work for the development of new DNV design guidelines on ice-structure interaction will be presented. The work will be completed in 2011 or early 2012. The project will be based on the new ISO 19906 standard, and will cover both fixed and floating installations. The paper also describes results from a recently completed real-time ice load monitoring program onboard an icebreaking vessel and shows correlation with proposed formulations.