Abstract Increased resource exploration and transportation in the Arctic has catalyzed the evaluation of equipment and procedures to determine their suitability for ice covered waters. Remote operating locations and harsh physical environments present new operational challenges and increased complexity that must be addressed to ensure environmental and personnel safety is not compromised. Emergency response in sea ice is a specific area that must be assessed to ensure that personnel are able to escape, evacuate, and be rescued in conditions that will be experienced during operations in the north. Regulators will expect that operators will be able to demonstrate that lifeboats can be safely launched and that the craft can navigate to a safe zone for rescue of personnel. The paper describes an investigation into the operability of conventional lifeboats in pack ice conditions. The investigation was based on field trials of a small Totally Enclosed Motor Propelled Survival Craft (TEMPSC) lifeboat that was operated in a range of controlled pack ice conditions. The study focused on observing how operators with different levels of experience and backgrounds operated in ice, how their behaviors impacted their ability to maneuver through the ice field and the impact on the vessel and crew. Participants in the trials had different levels of experience operating in ice and in small crafts. The coxswains who participated in the investigation had a range of operational experience with vessels in ice, including operators who have worked aboard icebreaking vessels, but with limited experience operating in small vessels, and operators with experience operating small vessels, but with limited experience operating in ice. During the field trials, coxswains employed different tactics for advancing through ice. The outcomes of the study were used to analyze the impact of different driving techniques on the ability of the coxswain to successfully maneuver through ice and the impact of driving style on vessel integrity and crew comfort. The results of the study assess the tactics which can be employed by coxswains in different ice concentrations and the outcomes can be used to define learning objectives for training programs designed to prepare coxswains for emergency operations in ice covered waters.
In this article the authors review the definitions of website usability from the 1990s to the present day and several approaches that have been used for the evaluation of university websites. Building on this experience they have developed a survey instrument to explore student views at their own institution, the University of Dhaka. The responses from the student population are analyzed by demographics, use, and the usefulness of the website. Only a small proportion of the survey population reported always finding what they needed. From the result, five factors are considered important for achieving usability: Interactivity and functionality; Navigation, searching and interface attractiveness; Accuracy, currency and authority of information; Accessibility, understandability, learnability and operability; Efficiency and reliability. Most students are not satisfied with the Dhaka University website and essential development is needed to improve content quality and accuracy.
This paper presents an analysis of local ice loads measured during full-scale field trials conducted in 2014 with a totally enclosed motor propelled survival craft (TEMPSC) in controlled pack ice conditions. These data were collected as part of an ongoing research program that aims to identify the limitations of conventional TEMPSC operating in sea ice environments and to provide insight as to how these limitations might be extended. During the 2014 trials, local ice loads were measured at two locations on the TEMPSC's bow area. These loads were the most severe measured to date and corresponded to an average ice floe mass that was approximately 1.25 times the mass of the fully loaded TEMPSC. The event-maximum method of local ice pressure analysis was used to analyze these field data to improve understanding of the nature of ice loads for such interactions and to evaluate the suitability of this approach for design load estimation for TEMPSCs (i.e., lifeboats) in ice. The event-maximum method was adapted for the present application, so as to link exceedance probabilities with design load levels for a given scenario. Comparison of the 2014 results with a previous analysis of 2013 field trials data supports earlier conclusions that these interactions are highly influenced by kinetic energy, since more massive ice floes are observed to impart significantly higher loads on the lifeboats. Illustrative examples examining the influence of ice concentration and sail-away distance have also been provided. The work establishes links between extreme loads and the exposure of the lifeboat to ice for different operating conditions. Based on this work it is concluded that the event-maximum method provides a promising approach for establishing risk-based design criteria for lifeboats if field data are available which adequately represent ice conditions encountered during the design life of the lifeboat.
Lifeboats are a ubiquitous means of evacuation fitted to offshore petroleum installations and marine vessels. For lifeboats operating in ice environments, the magnitude of local ice loads and the structural integrity of these crafts under ice loading are not well understood. To address these gaps, full-scale measurements relating to lifeboat-ice interactions were collected during a field campaign carried out in 2013. During this trial, the local ice loads on the hull of a Totally Enclosed Motor Propelled Survival Craft (TEMPSC) operating in pack ice conditions were measured using instrumented load panels. This full-scale field data provides the foundation for risk-based design load estimation and has been analyzed using the event-maximum method of local ice pressure analysis. This approach is based on probabilistic methods developed for the analysis of ice loads measured on icebreakers, which have been adapted for ice interaction scenarios involving small vessels. Results from this work provide improved insight into the nature of loads on lifeboats operating in ice-covered waters and help to inform design methodology for these vessels.
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