Assessment of Current Offshore Supply Vessel Capabilities for Crew Transfer Operations in the Flemish Pass

2018 ◽  
Author(s):  
Mitchell Anderson ◽  
David Molyneux
Keyword(s):  
Wave Height ◽  
Newfoundland And Labrador ◽  
Loading Condition ◽  
Oil And Gas ◽  
Time History ◽  
General Purpose ◽  
Ship Motions ◽  
Sea State ◽  
North East ◽  
Increased Risk

The Flemish Pass is a region off the coast of the province of Newfoundland and Labrador in which large oil discoveries have been made in recent years, making it a promising site for future offshore oil and gas developments. The site is located approximately 200 kilometers North-East of the currently producing Jeanne D’Arc Basin. This results in some additional challenges, including: higher waves and rougher seas on average, longer transit time from shore to any potential production facilities, and an increased risk of sea ice. Crew transfers from Offshore Supply Vessels (OSVs) to current production platforms offshore Newfoundland and Labrador are typically accomplished with a FROG-6 personnel-transfer capsule lifted by a platform-board crane. In current practice, for fixed platforms, this is only done when there is a Significant Wave Height (Hs) of 4.0 m or less, regardless of the OSV being used. In the winter months, this general-purpose approach does not allow for an acceptably high operational fraction of time in which crew transfers could be completed in the Flemish Pass. The FROG-6 capsule has designated operational limits based on the relative velocity between the capsule and the vessel deck, which will vary based on ship size, loading condition, and sea-state. Considering this, a series of geometrically similar OSV hull forms are created to represent the range of currently operating vessels. The developed models are between 70.0–90.0 m long, have a maximum breadth between 17.0–22.0 m, and block coefficients ranging from 0.65–0.79. Using ShipMo3D, a potential flow / panel code seakeeping solver, a 20 minute time history of ship motions is determined for all the modelled OSVs, across the range of sea-states realistically expected in the Flemish Pass. Then, a MATLAB script is used to transform these motions into deck velocities. From these results, the operational limits for crew transfer can be re-defined as a function of ship size, loading condition, and sea-state. This results in higher operability percentages than those achieved from using the flat wave height limit alone, with relatively large variations between differently sized and loaded ships. Further work must be done to officially implement new limits, such as: analysis of additional wave period and height combinations, further analysis of the time between limit exceedances, computational fluid dynamics simulations, “smart crane” modelling, and/or full scale sea trials.

Sea State Estimation Based on Ship Motions Measurements and Data Fusion

2013 ◽  
Author(s):  
Céline Drouet ◽  
Nicolas Cellier ◽  
Jérémie Raymond ◽  
Denis Martigny
Keyword(s):  
Data Fusion ◽  
State Estimation ◽  
Wave Height ◽  
Significant Wave Height ◽  
Wave Spectrum ◽  
Ocean Waves ◽  
Ship Motions ◽  
Sea State ◽  
Significant Wave ◽  
X Band

In-service monitoring can help to increase safety of ships especially regarding the fatigue assessment. For this purpose, it is compulsory to know the environmental conditions encountered: wind, but also the full directional wave spectrum. During the EU TULCS project, a full scale measurements campaign has been conducted onboard the CMA-CGM 13200 TEU container ship Rigoletto. She has been instrumented to measure deformation of the ship as well as the sea state encountered during its trip. This paper will focus on the sea state estimation. Three systems have been installed to estimate the sea state encountered by the Rigoletto: An X-band radar from Ocean Waves with WAMOS® system and two altimetric wave radars from RADAC®. Nevertheless, the measured significant wave height can be disturbed by several external elements like bow waves, sprays, sea surface ripples, etc… Furthermore, ship motions are also measured and can provide another estimation of the significant wave height using a specific algorithm developed by DCNS Research for the TULCS project. As all those estimations are inherently different, it is necessary to make a fusion of those data to provide a single estimation (“best estimate”) of the significant wave height. This paper will present the data fusion process developed for TULCS and show some first validation results.

Real Time Local Sea State Measurement using Wave Radar and Ship Motions

2010 ◽  
Author(s):  
E. M. Thornhill ◽  
D. C. Stredulinsky
Keyword(s):  
Real Time ◽  
Wave Height ◽  
Ship Motions ◽  
Sea State ◽  
State Measurement ◽  
Wave Radar ◽  
Directional Wave ◽  
Radar Measurements ◽  
Real Time Information ◽  
Canadian Navy

The Canadian Navy is exploring operator guidance systems designed to promote safer and more efficient operations in a seaway. These systems require accurate real time information on the local sea state. Recent sea trials with a wave radar system, which can produce directional wave spectra from the back scatter produced by conventional navigational radar, have generated good direction and frequency measurements, but wave height was found to be less reliable. However, by combining the wave radar measurements with ship motions, these wave height measurements are greatly improved. This paper presents some background of at-sea wave measurement, a description of the combined wave radar / ship motions procedure, and the results from several sea trials.

scholarly journals ANALYTICAL MODELLING OF SEAKEEPING QUALITIES OF CONTAINER VESSEL

2020 ◽  
Vol 30 (1) ◽  
pp. 78-87
Author(s):  
N. M. Konon ◽  
◽  
◽  
◽  
Keyword(s):  
Wave Height ◽  
Wave Spectrum ◽  
Ship Design ◽  
Design Parameters ◽  
Ship Motions ◽  
Height Distribution ◽  
Added Resistance ◽  
Sea State ◽  
Wave Data ◽  
Deck Wetness

The design of ships or any other floating systems intended to operate on or close to the surface of the sea is controlled to a large extent by what is usually referred to as seakeeping, or, in more common terminology, safety at sea. This is a primary consideration and criteria, which has to be fully met. Safety of a ship naturally includes the crew, cargo and the hull itself. Seakeeping is, indeed, a generalized term and reflects the ship's capability to survive all hazards at sea such as collision, grounding, fire, as well as heavy-weather effects related to the environment in general and waves in particular. The two most likely types of failure under these conditions are due to structural causes and capsizing resulting from insufficient stability under severe weather conditions. Such criteria as economical navigation of the ship as related to speed-keeping abilities, fuel consumption, avoidance of damage to ship components and cargo, and comfort to crew or passengers, or both, are key items. The operational limits of electronic equipment, mechanical components and weapon systems on board warships are other aspects of sea keeping. In this work it is highlighted that seakeeping is a generalized term that includes a wide variety of subjects such as ship motions (amplitudes, accelerations, phases), deck wetness, slamming, steering in waves, added resistance, hydrodynamic loadings (pressures, forces, moments) and transient loads. Since the ship environmental operability or its sea keeping characteristics are closely linked to the severity of the sea, the description of the seaway is usually considered as an integral part of sea keeping. It is taken into consideration that the severity of the sea cannot be considered in absolute terms, since for each floating system, be it a ship, a platform or a buoy, the intensity of the sea state can only be determined in terms of the system's responses. Hence, different thresholds apply to different problems, and sea state 4 may be just as severe for a small patrol craft as sea state 8 may be for a larger containership. Hence, the characteristics and frequency of occurrence of waves in specific sea zones are required if a possible reduction in the system environmental operability is expected. It is demonstrated that most texts or papers, which deal with the overall question of sea keeping, devote some attention to the basic phenomena, that is, the seaway and the motions of the ship or other floating platforms as a result of the excitation imposed by the seaway. Ship motions, as such, do not always constitute the criteria for sea keeping, and much more often other responses directly related to the magnitude and phasing of the motions or the resulting velocities and accelerations constitute the prime cause for exhibiting good or bad sea keeping qualities. Such responses could be a function of the motion only, as in the case of added resistance or hydrodynamic pressures, or they could be a function of motion and other design parameters, such as freeboard in the case of deck wetness or the longitudinal weight distribution in the case of vertical bending moments. In this work, latest methods of modeling and computation for body-wave interactions described and compared with data observed for container carrier. The foregoing calculation routine Судноводіння | Shipping & Navigation ISSN 2306-5761 | 2618-0073 30-2020 Національний університет «Одеська морська академія» 79 is fairly well accepted today among naval architects specializing in the sea keeping aspects of the ship design process. Differences between the results obtained by various techniques as presented by the available computer programs are insignificant. However, since the regular-wave results are of little or no value except as input for the more realistic long- and short-term response predictions in a real seaway environment, it is important to determine which wave data information and what statistical extrapolation techniques are used to obtain the latter. The format used to describe the seaway in most ship response calculations is the wave spectrum. However, since measured spectrum for a specific sea zone or route are very rarely available, it is often necessary to use spectrum measured in one location for predictions in another location. In such a case, while the basic spectruml shape and scatter remain unchanged, the percentage of wave height distribution would vary to represent realistic conditions for the sea area in question. Such data usually are based on observations, and assuming the sample is large enough the distribution of expected wave heights should be quite reliable. An alternative approach often used in ship design is to utilize one of several theoretical spectruml formulations [2, 3, 4] such as the Pierson-Moskowitz one-parameter spectrum, the ISSC spectrum, the JONSWAP spectrum, and other. In each of these cases, some input parameters are required usually in the form of wave height, period, peak frequency, fetch, etc. The reliability of the wave data depends in these cases both on the quality of the input parameter and the adequacy of the theoretical formulation.

scholarly journals Estimation of Significant Wave Heights from ASCAT Scatterometer Data via Deep Learning Network

2021 ◽  
Vol 13 (2) ◽  
pp. 195
Author(s):  
He Wang ◽  
Jingsong Yang ◽  
Jianhua Zhu ◽  
Lin Ren ◽  
Yahao Liu ◽  
...  
Keyword(s):  
Deep Learning ◽  
Wave Height ◽  
Significant Wave Height ◽  
Incidence Angle ◽  
Ocean Waves ◽  
Global Scale ◽  
Learning Technology ◽  
Sea State ◽  
Significant Wave ◽  
Wave Heights

Sea state estimation from wide-swath and frequent-revisit scatterometers, which are providing ocean winds in the routine, is an attractive challenge. In this study, state-of-the-art deep learning technology is successfully adopted to develop an algorithm for deriving significant wave height from Advanced Scatterometer (ASCAT) aboard MetOp-A. By collocating three years (2016–2018) of ASCAT measurements and WaveWatch III sea state hindcasts at a global scale, huge amount data points (>8 million) were employed to train the multi-hidden-layer deep learning model, which has been established to map the inputs of thirteen sea state related ASCAT observables into the wave heights. The ASCAT significant wave height estimates were validated against hindcast dataset independent on training, showing good consistency in terms of root mean square error of 0.5 m under moderate sea condition (1.0–5.0 m). Additionally, reasonable agreement is also found between ASCAT derived wave heights and buoy observations from National Data Buoy Center for the proposed algorithm. Results are further discussed with respect to sea state maturity, radar incidence angle along with the limitations of the model. Our work demonstrates the capability of scatterometers for monitoring sea state, thus would advance the use of scatterometers, which were originally designed for winds, in studies of ocean waves.

Pregnancy outcomes of women with and without a history of anorexia nervosa

2012 ◽  
Vol 42 (12) ◽  
pp. 2651-2660 ◽  
Author(s):  
J. M. Eagles ◽  
A. J. Lee ◽  
E. Amalraj Raja ◽  
H. R. Millar ◽  
S. Bhattacharya
Keyword(s):  
Anorexia Nervosa ◽  
Pregnancy Outcomes ◽  
Intrauterine Growth Restriction ◽  
Maternal Body Mass Index ◽  
Intrauterine Growth ◽  
North East ◽  
Increased Risk ◽  
History Of ◽  
Obstetric Services ◽  
Adverse Pregnancy

BackgroundWhen women have a history of anorexia nervosa (AN), the advice given about becoming pregnant, and about the management of pregnancies, has usually been cautious. This study compared the pregnancy outcomes of women with and without a history of AN.MethodWomen with a confirmed diagnosis of AN who had presented to psychiatric services in North East Scotland from 1965 to 2007 were identified. Those women with a pregnancy recorded in the Aberdeen Maternal and Neonatal Databank (AMND) were each matched by age, parity and year of delivery of their first baby with five women with no history of AN. Maternal and foetal outcomes were compared between these two groups of women. Comparisons were also made between the mothers with a history of AN and all other women in the AMND.ResultsA total of 134 women with a history of AN delivered 230 babies and the 670 matched women delivered 1144 babies. Mothers with AN delivered lighter babies but this difference did not persist after adjusting for maternal body mass index (BMI) in early pregnancy. Standardized birthweight (SBW) scores suggested that the AN mothers were more likely to produce babies with intrauterine growth restriction (IUGR) [relative risk (RR) 1.54, 95% confidence interval (CI) 1.11–2.13]. AN mothers were more likely to experience antepartum haemorrhage (RR 1.70, 95% CI 1.09–2.65).ConclusionsMothers with a history of AN are at increased risk of adverse pregnancy outcomes. The magnitude of these risks is relatively small and should be appraised holistically by psychiatric and obstetric services.

Post-stroke memory deficits and barriers to seeking help: views of patients and carers

2018 ◽  
Vol 36 (4) ◽  
pp. 506-510 ◽  
Author(s):  
Eugene Y H Tang ◽  
Christopher Price ◽  
Blossom C M Stephan ◽  
Louise Robinson ◽  
Catherine Exley
Keyword(s):  
Health Professionals ◽  
Health Care Professionals ◽  
Organizational Level ◽  
Stroke Survivors ◽  
Ageing Population ◽  
Family Carers ◽  
Post Stroke ◽  
North East ◽  
Increased Risk ◽  
Seeking Help

Abstract Background Memory and cognitive deficits post stroke are common and associated with increased risk of future dementia. Rehabilitation tends to focus on physical recovery; however, once in the community, it is unclear what happens in the longer term to the stroke-survivor with new memory difficulties. Objective The aim of this qualitative study was to examine in stroke-survivors what factors influence contact with health professionals. Method Semi-structured interviews were conducted with stroke-survivors and their family carers where memory difficulties were reported at 6 months post stroke. A topic guide was used which sought to critically examine participants care experience following their stroke diagnosis. All participants were interviewed at baseline (around 6 months post stroke) and offered an interview at around 12 months post stroke. All interviews were conducted in the North East of England. All transcripts were coded and thematically analysed. Results Ten stroke-survivors (age range 72–84 years) were interviewed alongside five carers at baseline; eight stroke-survivors and four carers agreed to a follow-up interview. Three main barriers were identified: (i) fear of a dementia diagnosis; (ii) denial or minimization of symptoms leading to adaptation and (iii) obstacles to seeking help in the community. Conclusions With an ageing population and increase in stroke-survival, the burden of post-stroke cognitive impairment and dementia will only increase. Stroke-survivors and their family carers in this study have identified issues that may hinder their presentation to health care professionals at a personal and organizational level. Health professionals need to be aware of these potential issues when planning services for stroke-survivors.

scholarly journals Operability Guidelines For Product Tanker In Heavy Weather In The Adriatic Sea

2014 ◽  
Vol 21 (1) ◽  
pp. 95-106
Author(s):  
Luka Mudronja ◽  
Marko Katalinić ◽  
Rino Bošnjak ◽  
Pero Vidan ◽  
Joško Parunov
Keyword(s):  
Wave Height ◽  
Adriatic Sea ◽  
Wave Spectrum ◽  
Extreme Weather ◽  
The South ◽  
Sea State ◽  
M Wave ◽  
The North ◽  
Limiting Values ◽  
Deck Wetness

AbstractThis paper presents operability guidelines for seafarers on a product tanker which navigates in the Adriatic Sea during heavy weather. Tanker route starts from the Otranto strait in the south to the island Krk in the north of Adriatic Sea. Heavy weather is caused by south wind called jugo (blowing from E-SE to SS-E, sirocco family). Operability guidelines are given based on an operability criteria platform for presenting ship seakeeping characteristics. Operability criteria considered in this paper are propeller emergence, deck wetness and bow acceleration of a product tanker. Limiting values of mentioned criteria determine sustainable speed. Heavy weather is described by extreme sea state of 7.5 m wave height. Wave spectrum used in this paper is Tabain spectrum which is developed specifically for Adriatic Sea. Seafarer's approach of decisions making in extreme weather is also shown and servers as a guideline for further research of the authors.

scholarly journals Factors associated with COVID-19 related hospitalisation, critical care admission and mortality using linked primary and secondary care data

2021 ◽  
Author(s):  
Lisa Cummins ◽  
Irene Ebyarimpa ◽  
Nathan Cheetham ◽  
Victoria Tzortziou Brown ◽  
Katie Brennan ◽  
...  
Keyword(s):  
Risk Factors ◽  
Learning Disabilities ◽  
Secondary Care ◽  
Multivariate Logistic Regression Analysis ◽  
Additional Patient ◽  
Factors Associated ◽  
Icu Admission ◽  
Risk Of Death ◽  
North East ◽  
Increased Risk

AbstractBackgroundTo identify risk factors associated with increased risk of hospitalisation, intensive care unit (ICU) admission and mortality in inner North East London (NEL) during the first UK COVID-19 wave.MethodsMultivariate logistic regression analysis on linked primary and secondary care data from people aged 16 or older with confirmed COVID-19 infection between 01/02/2020-30/06/2020 determined odds ratios (OR), 95% confidence intervals (CI) and p-values for the association between demographic, deprivation and clinical factors with COVID-19 hospitalisation, ICU admission and mortality.ResultsOver the study period 1,781 people were diagnosed with COVID-19, of whom 1,195 (67%) were hospitalised, 152 (9%) admitted to ICU and 400 (23%) died. Results confirm previously identified risk factors: being male, or of Black or Asian ethnicity, or aged over 50. Obesity, type 2 diabetes and chronic kidney disease (CKD) increased the risk of hospitalisation. Obesity increased the risk of being admitted to ICU. Underlying CKD, stroke and dementia in-creased the risk of death. Having learning disabilities was strongly associated with increased risk of death (OR=4.75, 95%CI=(1.91,11.84), p=0.001). Having three or four co-morbidities increased the risk of hospitalisation (OR=2.34,95%CI=(1.55,3.54),p<0.001;OR=2.40, 95%CI=(1.55,3.73), p<0.001 respectively) and death (OR=2.61, 95%CI=(1.59,4.28), p<0.001;OR=4.07, 95% CI= (2.48,6.69), p<0.001 respectively).ConclusionsWe confirm that age, sex, ethnicity, obesity, CKD and diabetes are important determinants of risk of COVID-19 hospitalisation or death. For the first time, we also identify people with learning disabilities and multi-morbidity as additional patient cohorts that need to be actively protected during COVID-19 waves.

scholarly journals STATISTICAL PROPERTIES OF THE MAXIMUM RUN OF IRREGULAR SEA WAVES

1988 ◽  
Vol 1 (21) ◽  
pp. 48 ◽  
Author(s):  
Akira Kimura
Keyword(s):  
Probability Distribution ◽  
Wave Height ◽  
Probability Distributions ◽  
Confidence Regions ◽  
Statistical Properties ◽  
Irregular Waves ◽  
Sea Waves ◽  
Sea State ◽  
Irregular Wave ◽  
Distribution Of The Maximum

The probability distribution of the maximum run of irregular wave height is introduced theoretically. Probability distributions for the 2nd maximum, 3rd maximum and further maximum runs are also introduced. Their statistical properties, including the means and their confidence regions, are applied to the verification of experiments with irregular waves in the realization of a "severe sea state" in the test.

scholarly journals Investigations of detrital zircon, rutile and titanite from present-day Labrador drainage basins: fingerprinting the Grenvillean front

1969 ◽  
pp. 77-80
Author(s):  
Tonny B. Thomsen ◽  
Christian Knudsen ◽  
Alana M. Hinchey
Keyword(s):  
Newfoundland And Labrador ◽  
Sedimentary Basins ◽  
Geological Survey ◽  
Drainage Basins ◽  
Grenville Province ◽  
Collaborative Project ◽  
North West ◽  
North East ◽  
The North ◽  
Three Samples

A multidisciplinary provenance study was conducted on stream sediment samples from major rivers in the eastern part of Labrador, Canada (Fig. 1). Th e purpose was to fi ngerprint the sources that deliver material to the stream sediments and to the reservoir sand units deposited off shore in the sedimentary basins in the Labrador Sea. We used a multimineral U-Pb geochronological approach employing rutile and titanite in addition to zircon to obtain unbiased age data. Th e purpose of this was to characterise the diff erent igneous and metamorphic episodes that occurred in Labrador, which is an area with highly variable geology characterised by the Palaeoproterozoic south-eastern Churchill province in the north-west, the Archaean Nain plutonic suite in the north-east, the Palaeoproterozoic Makkovik province in the east and the Mesoproterozoic Grenville Province to the south. Th e fi eld work was carried out in 2012 and 2013 and the study is a collaborative project between the Geological Survey of Denmark and Greenland and the Geological Survey of Newfoundland and Labrador. In this paper we focus on three samples from the southern part of the study area where two parts of the Grenville orogeny are found (Fig. 1).

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