Knowledge

Keyword: maritime safety

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Recommended action to facilitate ship crew change, access to medical care and seafarer travel during the COVID-19 pandemic, 21st September 2020 (IMO Doc MSC.473(ES.2), IMO Doc ALCOM/ES/WP.1/Add.1/Rev.1 Annex I), OXIO 627

Nelson F. Coelho

The content of Resolution MSC.473(ES.2) can be summarized in five main points and one invitation to IMO Member States.

The first point pertains to the implementation of the Framework of Protocols. The second point pertains to the designation of seafarers as 'key workers' in order to facilitate safe and unhindered movement for embarking or disembarking a vessel. The third point pertains to the consideration of temporary migration measures to ease mobility of seafarers, eg waivers or relaxations of visa or documentary requirements. The fourth point is on the use of prevention measures such as testing crews before embarkation; this requires active conduct by port states, namely providing access to personal protective equipment and testing facilities. The fifth point is on providing seafarers with immediate access to medical care and facilities, as well as with evacuation when the assistance required cannot be provided on board or at port; this aims to prevent humanitarian situations such as casualties on board vessels due to lack of access to intensive care units.

Furthermore, the Resolution invites Member States to designate a National Focal Point on Crew Change and Repatriation of Seafarers ('National Focal Point').

Oxford University Press / 2022
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Protection Systems for DC Shipboard Microgrids

Navid Bayati & Mehdi Savaghebi

In recent years, shipboard microgrids (MGs) have become more flexible, efficient, and reliable. The next generations of future shipboards are required to be equipped with more focuses on energy storage systems to provide all-electric shipboards. Therefore, the shipboards must be very reliable to ensure the operation of all parts of the system. A reliable shipboard MG should be pro-tected from system faults through protection selectivity to minimize the impact of faults and facili-tate detection and location of faulty zones with the highest accuracy and speed. It is necessary to have an across-the-board overview of the protection systems in DC shipboards. This paper provides a comprehensive review of the issues and challenges faced in the protection of shipboard MGs. Furthermore, given the different types of components utilized in shipboard MGs, the fault behavior analysis of these components is provided to highlight the requirements for their protection. The protection system of DC shipboards is divided into three sub-systems, namely, fault detection, lo-cation, and isolation. Therefore, a comprehensive comparison of different existing fault detection, location, and isolation schemes, from traditional to modern techniques, on shipboard MGs is presented to highlight the advantages and disadvantages of each scheme.

Energies / 2021
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Analysis of structural crashworthiness of double-hull ships in collision and grounding

Liu, Bin; Villavicencio, Richard; Pedersen, Preben Terndrup; Guedes Soares, C.

A conceptual design framework for collision and grounding analysis is proposed to evaluate the crashworthiness of double-hull structures. This work attempts to simplify the input parameters needed for the analysis, which can be considered as a step towards a design-oriented procedure against collision and grounding. Four typical collision and grounding scenarios are considered: (1) side structure struck by a bulbous bow, (2) side structure struck by a straight bow, (3) bottom raking, (4) bottom stranding. The analyses of these scenarios are based on statistical data of striking ship dimensions, velocities, collision angles and locations, as well as seabed shapes and sizes, grounding depth and location. The evaluation of the damage extent considers the 50- and 90-percentile values from the statistics of collision and grounding accidents. The external dynamics and internal mechanics are combined to analyse systematically the ship structural damage and energy absorption under accidental loadings.

Marine Structures, Volume 76 / 2020
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Probability and Mechanics of Ship Collision and Grounding

Shengming Zhang, Preben Terndrup Pedersen, Richard Villavicencio

Ship collision and grounding events constitute a major hazard for ship operations, and ship collision risk analyses have to be carried out for installations such as offshore structures for extraction of hydrocarbons, offshore wind farms, and bridges spanning waterways. This book provides assessment procedures for ship collision and grounding analysis and includes probabilistic methods for collision and grounding risk assessment, estimation of the energy released during collisions, and prediction of the extent of damage on the involved structures.
The main feature of the book is that it encapsulates reliable and fast analysis methods for collision and grounding assessment and the methods have been extensively validated with experimental and numerical results. In addition, all the described analysis methods include realistic calculation examples so as to provide confidence in their use to eventually conduct the required assessment according to the rules and design codes. The book is intended as a handbook for professionals and researchers in the industry dealing with design and analysis of ships and offshore structures. The book can also be used as a text book for postgraduate courses orientated towards the design and analysis of ship and offshore structures.

Elsevier / 2019
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Delivering Refugees and Migrants to a ‘Place of Safety’ Following Rescue by States at Sea

Fenella Billing

Irregular migration by sea leads states such as Italy and Australia to conduct maritime rescue operations involving refugees and other migrants. During these operations, states must deal with the question of where to disembark survivors. The law of the sea regime obliges states to ensure survivors are delivered to a 'place of safety', arguably requiring maritime officers to merely consider the physical safety of survivors immediately on disembarkation. Non-binding International Maritime Organization guidelines state that the need to avoid disembarking refugees and asylum-seekers in the states of departure or origin is also a consideration. The guidelines refer to other 'relevant' international law, including treaties dealing with 'refugee refoulement' or refoulement in connection with a risk of torture. Under the international human rights law regime, including international refugee law, states' obligations in relation to non-refoulement are broader and prohibit the return of refugees and migrants to states where they directly or indirectly face persecution, torture or other serious harm. In interpreting 'place of safety', this work argues that there is insufficient consensus to integrate the two legal regimes. Nevertheless, states can be under co-existing human rights obligations that place limits on the disembarkation of rescued refugees and migrants.

Maritime Safety and Security Law Journal / 2019
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Smart-Spider: Autonomous self-driven in-line robot for versatile pipeline inspection

Ying Qu, Petar Durdevic & Zhenyu Yang

This paper presents the design and development of a conceptual prototype of an autonomous self-driven inline inspection robot, called Smart-Spider. The primary objective is to use this type of robot for offshore oil and gas pipeline inspection, especially for those pipelines where the conventional intelligent pigging systems could not or be difficult to be deployed. The Smart-Spider, which is real-time controlled by its own on-board MCU core and power supplied by a hugged-up battery, is expected to execute pipeline inspection in an autonomous manner. A flexible mechanism structure is applied to realize the spider's flexibility to adapt to different diameters of pipelines as well as to handle some irregular situations, such as to pass through an obstructed areas or to maneuver at a corner or junction. This adaptation is automatically controlled by the MCU controller based on pressure sensors' feedback. The equipped devices, such as the selected motors and battery package, as well as the human-and-machine interface are also discussed in detail. Some preliminary laboratory testing results illustrated the feasibility and cost-effectiveness of this design and development in a very promising manner.

IFAC-PapersOnLine / 2018
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Challenges in Slug Modeling and Control for Offshore Oil and Gas Productions: A Review Study

Simon Pedersen, Petar Durdevic & Zhenyu Yang

The upstream offshore multi-phase well-pipeline-riser installations are facing huge challenges related to slugging flow: An unstable flow regime where the flow rates, pressures and temperatures oscillate in the multi-phase pipelines. One typical severe slug is induced by vertical wells or risers causing the pressure to build up and hence originates the oscillating pressure and flow. There exist many negative consequences related to the severe slugging flow and thus lots of investments and effort have been put into reducing or completely eliminating the severe slug. This paper reviews in detail the state-of-the-art related to analysis, detection, dynamical modeling and elimination of the slug within the offshore oil & gas Exploration and Production (E&P) processes. Modeling of slugging flow has been used to investigate the slug characteristics and for design of anti-slug control as well, however most models require specific facility and operating data which, unfortunately, often is not available from most offshore installations. Anti-slug control has been investigated for several decades in the oil & gas industry, but many of these existing methods suffer the consequent risk of simultaneously reducing the oil & gas production. This paper concludes that slug is a well defined phenomenon, but even though it has been investigated for several decades the current anti-slug control methods still have problems related to robustness. It is predicted that slug-induced challenges will be even more severe as a consequence of the longer vertical risers caused by deep-water E&P in the future.

International Journal of Multiphase Flow / 2017
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Review of Slug Detection, Modeling and Control Techniques for Offshore Oil & Gas Production Processes

Simon Pedersen, Petar Durdevic & Zhenyu Yang

The current offshore oil & gas multi-phase production and transportation installations have big challenges related to the slugging flow: An unstable multi-phase flow regime where the flow rates, pressures and temperatures oscillate in the considered processes. Slug can be caused by different operating conditions and installation structures. The most severe slugs are often induced in long vertical risers or production wells, where liquid blocks gas at the riser/well base and correspondingly it causes the pressure to accumulate and hence originates the oscillating performance. There are many severe consequences to the production processes because of the slugging flow. This paper reviews some observed latest status and key challenges about slug detection, dynamical modeling and elimination of slugging flows. Mathematical modeling of slug has been used to investigate the slug mechanism and anti-slug control. Most of available models are based on mass-balance formulations, which often require sufficient data for reliable parameter tuning/identification. Slug elimination and control have been investigated for many years and there exist many solutions to eliminate the slug, but some of these methods can simultaneously reduce the oil & gas production, which is a very big concern as the production rate is the key evaluation parameter for offshore production. We conclude that the slugging flow is a well-defined phenomenon, even though this subject has been extensively investigated in the past decades, the cost-effective and optimal slug modeling and control are still open topics with many related challenges.

IFAC-PapersOnLine / 2015
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Collisions damage assessment of ships and jack-up rigs

Zhang, Shengming; Pedersen, Preben Terndrup; Ocakli, Hasan

Ship collision with offshore installations is one of the key concerns in design and assess of platforms performance and safety. This paper presents an analysis on collision energy and structural damage in ship and offshore platform collisions for various collision scenarios. The platform or rig is treated as either rigid or flexible and its sensitivity on collision energy and structural damage is studied. An application example where an ice-strengthened supply vessel collides against a jack-up rig is analysed and the crushing resistance of the involved thin-walled structures is evaluated.

Ships and Offshore Structures, Volume 10 / 2015
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Online Slug Detection in Multi-phase Transportation Pipelines Using Electrical Tomography

Simon Pedersen, Christian Mai, Leif Hansen, Petar Durdevic & Zhenyu Yang

Slugging flow in offshore oil & gas multi-phase transportation pipelines cause big challenges as the flow regime induces flow and pressure oscillations in the multi-phase pipelines. The negative impacts of the most severe slugs are significant and thus the elimination of slugging flow in the pipelines is a highly investigated topic. To eliminate the slug in an online manner real-time slug detection methods are often required. Traditionally topside pressure transmitters upstream of a 3-phase separator have been used as the controlled variable. In this paper Electrical Resistivity Tomography (ERT) has been examined as an alternative to the traditional pressure transmitters. A lab-scaled testing facility has been constructed in order to obtain test data from an ERT transmitter with 12 probes. Different flow regimes have been generated by a pump and a compressor where 2-phase flow can be tested. Based on the results, the study concludes that the ERT is able to detect the slug very well when the oil and water are well mixed. Furthermore, the traditional pressure transmitters have the limitation that pressure variations can be caused by other operating conditions than slug, such as change in the back pressure from control valves. The biggest limitation using ERT is the lack of ability to distinguish between gas and oil, and thus the ERT can only be used as an effective slug detect measurement when the oil-to-water ratio is low.

IFAC-PapersOnLine / 2015
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