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Torgeir Moan - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Oil Spill Risk in DP Shuttle Tanker Direct Offloading Operations
Volume 2: Structures Safety and Reliability, 2011Co-Authors: Haibo Chen, Torgeir Moan, Arve Lerstad, Ka˚re BreivikAbstract:DP Shuttle Tankers performing offloading directly from fixed or geostationary floating offshore installations is addressed in this paper. It is important to ensure that disconnection of offloading hose can be achieved in time given Shuttle Tanker DP failure and position loss. The accident scenario is the hose fail-to-disconnect while Shuttle Tanker has an excessive position excursion. The consequence can be oil spill combined with the damage the offloading system. The spill amount can be as much as the crude oil volume in the hose, or over 1000 m3 if isolation and shutdown of oil export pump on the installation are not achieved timely. Various barriers to prevent oil spill have been developed over the past 30 years’ history of Shuttle Tanker offshore loading. However, the direct offloading is a new operational context to the traditional offloading. A quantitative frequency model for oil spill initiated by DP Shuttle Tanker position loss in direct offloading is presented in this paper. Case study results show that in the base case where only traditional barriers are used, the frequency for large oil spill up to 1000 m3 or more may reach 2.48E−03 per year, given 20 hours offloading cargo transfer time and 52 times offloadings per year. This frequency is not negligible, and risk reduction measures are viewed necessary. Novel safety barriers, i.e. Automatic Shutdown and Release (ASDR), as well as the HPR (Hydroacoustic Position Reference) and BLS (Bow Loading System) weak link mode, are analyzed as sensitivity cases. Results show that the frequency of large oil spill can then be reduced to 3.81E−05 per year, i.e. 1.5% of the base case value, and this is well within 1.0E−04 per year level. Recommendations to minimize oil spill risk during DP Shuttle Tanker direct offloading operations are proposed in this paper.Copyright © 2011 by ASME
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Probabilistic Evaluation of Collision Between DP Shuttle Tanker and Geostationary FPSO in Direct Offloading
29th International Conference on Ocean Offshore and Arctic Engineering: Volume 2, 2010Co-Authors: Haibo Chen, Arve Lerstad, Torgeir MoanAbstract:A geostationary FPSO does not weathervane like a turret-moored ship-shaped FPSO. The offshore industry has limited experience for direct offloading from such geostationary installations in the North Sea. In recent years direct offloading operations from geostationary FPSOs by DP Shuttle Tankers, have been developed, and key operational principles for such a system are presented in this paper. Probabilistic modeling of the collision risk between Shuttle Tanker and geostationary FPSO in direct offloading is presented, followed by a case study. It is found that the collision risk level is much lower in the direct offloading than in the tandem offloading. The results demonstrate that the direct offloading approach is a promising concept with inherent safety designed in the operations, i.e. the positioning philosophy of the Shuttle Tanker and a large separation distance.© 2010 ASME
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FPSO-Shuttle Tanker Collision Risk Reduction
Journal of Offshore Mechanics and Arctic Engineering-transactions of The Asme, 2005Co-Authors: Haibo Chen, Torgeir MoanAbstract:To reduce the occurrence of Tanker drive-off, and to reduce the probability of recovery failure should drive-off happen, are two basic principles to reduce FPSO and DP Shuttle Tanker collision in tandem offloading. In this paper we focus on measures to reduce recovery failure. Previous analyses revealed that recovery failure probability is high due to a lack of time for the DP operator to initiate the recovery action in a Tanker drive-off scenario. To increase the time window and to reduce the operator reaction time are therefore two main principles of recovery failure reduction. A substantial increase of the separation distance between FPSO and the Tanker, and a possible reduction of the main propeller(s) forward thrust that can be used by the Tanker DP system are two measures to increase the time window. The effective reduction of operator reaction time can be achieved by a number of measures, i.e., selection, training, procedure, crew resource management, and automation support, which are designed to improve early detection as well as effectively reduce the DP operator’s time in diagnosis and situation awareness.
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probabilistic modeling and evaluation of collision between Shuttle Tanker and fpso in tandem offloading
Reliability Engineering & System Safety, 2004Co-Authors: Haibo Chen, Torgeir MoanAbstract:Abstract DP Shuttle Tanker drive-off in tandem offloading poses a threat of collision to Floating Production, Storage, and Offloading unit (FPSO) with potential serious consequences. A two-stage probabilistic model of FPSO and Tanker collision in the tandem offloading operation is developed. The first part of analyses based on this model deals with Tanker drive-off scenarios. Findings reveal that the Tanker drive-off frequency in tandem offloading is high. Based on analyses of incidents, failure prone situations, termed as excessive surging and yawing, under which Tanker drive-off frequently happened, are identified. Measures to eliminate excessive surging and yawing, which ultimately reduce Tanker drive-off occurrence, are proposed. The second part of analyses deals with recovery action initiated by Tanker DP operator in drive-off scenario. Given the favored recovery strategy by the majority of operators, analyses revealed that recovery failure probability is still high due to lack of time for DP operator to initiate the recovery action in Tanker drive-off scenario. Measures to increase available time, and to reduce operator reaction time, are proposed to reduce the recovery failure.
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Prediction of Relative Motion and Probability of Contact Between FPSO and Shuttle Tanker in Tandem Offloading Operation
Journal of Offshore Mechanics and Arctic Engineering-transactions of The Asme, 2003Co-Authors: Haibo Chen, Torgeir Moan, Sverre Haver, Kjell LarsenAbstract:Excessive relative motions between Floating Production Storage Offloading Unit (FPSO), and Tanker, which are termed as excessive surging and yawing events, are identified as the “failure prone situation” in tandem offloading. These events have contributed to the initiation of Tanker drive-off in most collision incidents that happened in the North Sea in recent years. To estimate and reduce the probability of excessive surging and yawing events in tandem offloading, a simulation-based approach, which is based on a state-of-the-art time-domain simulation code SIMO, is presented in this paper. A typical North Sea FPSO and a DP Shuttle Tanker simulation models are setup in SIMO and calibrated by full-scale measurements. The simulated relative distance and relative heading between FPSO and Tanker are analyzed by fitting their extreme values into statistical models which give out probabilities of excessive surging and yawing events. Sensitivity studies are performed to pinpoint contributions from various technical and operational factors. Measures to minimize the occurrence of excessive surging and yawing events are identified in design and operational perspectives.
Eduardo A. Tannuri - One of the best experts on this subject based on the ideXlab platform.
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Equilibrium Position Analysis for Offloading Operations With Turret-Moored FPSO
Journal of Offshore Mechanics and Arctic Engineering-transactions of The Asme, 2019Co-Authors: Alex S. Huang, Eduardo A. Tannuri, Felipe M. Moreno, Joselito G. A. CâmaraAbstract:With the expansion of oil exploration in deep waters, assessing the risks associated with offloading operations becomes essential in preventing accidents that may cause huge environmental disasters. In this paper, the system that composed of a turret-moored floating production storage and offloading (FPSO) connected to a conventional Shuttle Tanker, which is assisted by a tug boat to maintain its position during an offloading operation, will be studied. Using environmental data collected over a period of 6 years, from 2004 to 2009, from the Campos Basin in Brazil, the equilibrium positions of the system were calculated, considering its constraints (operational criteria defined by Petrobras) and verifying the stability of those equilibrium points. The hydrodynamic and aerodynamic static forces were calculated using models validated in the literature. Dynamic effects and oscillations are taken into account by adding safety margins to the operational sectors. With this analysis, we calculated the FPSO heading probabilities during an offloading operation and the expected downtime of operation in Campos Basin. We concluded that the downtime of the offloading operation with a conventional Shuttle Tanker is close to that with a dynamic positioned (DP) Shuttle Tanker (10% downtime). Furthermore, the results from the stability analysis were used to generate a simplified set of rules to classify the environmental conditions into four classes of operational risk by applying an unbiased decision tree. This method obtains practical rules based on measurements of wind, wave, and current, allowing the operator to quickly evaluate the risk level before starting the operation.
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FPSO AND MONOBUOY OFFLOADING OPERATION WITH A CONVENTIONAL Shuttle Tanker: DIMENSIONING OF TUGBOAT BASED ON NUMERICAL SIMULATION
IFAC Proceedings Volumes, 2016Co-Authors: Eduardo A. Tannuri, Fernando Gomes Da Silva Torres, Haroldo Igreja, Isaias Quaresma MasettiAbstract:Abstract In the present paper, a numerical simulation analysis of FPSO and monobuoy tug-assisted offloading operation is carried out. The main objective is to define the required tug-force that must be applied in the Shuttle Tanker in order to guarantee a safe operation. Critical environmental conditions of Brazilian waters are used, and a full time domain computational simulator is used to estimate vessels motions and hawser forces during the operation. Operational criteria adopted by Petrobras were then used to verify the risks associated to each operation. Such procedure was used to define the minimum requirements for the offloading assistance tugboats.
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Comprehensive Downtime Analysis of DP-Assisted Offloading Operation of Spread Moored Platforms in Brazilian Waters
Volume 1: Offshore Technology, 2013Co-Authors: Diego Cascelli Corrêa, Eduardo A. Tannuri, Allan C. De Oliveira, Sergio H. SphaierAbstract:Oil offloading from Spread Mooring System (SMS) FPSO is usually done by means of a dynamically positioned Shuttle Tanker (DPST) in tandem configuration. The ST receives the oil pumped by the FPSO from a bow or stern offloading station, and the operation may take up to 3 days. In order to minimize the risks associated with the operation, the Shuttle Tanker (ST) should be kept within a safety zone with respect to the FPSO, which is usually given as a minimum distance between the two ships and an aperture angle from the FPSO centerline. In order to guarantee the Tanker position during the whole operation, the operation must be performed with Tankers provided with DP (dynamic positioning) systems. Since SMS FPSOs may be not aligned to the environmental forces, keeping the Shuttle Tanker in position may be a hard task for the DP system, depending on the environmental conditions. There are non-rare situations in which the ST must be disconnected and the operation interrupted.The present paper applies a methodology based on static calculation of DP capacity for evaluating the downtime of such offloading operation. The three generations of DP Tankers applied in Brazilian waters are considered. Santos and Campos Basin long-term (8-year) environmental conditions (current, wind, local-sea and swell) are used in the downtime calculation. The main objective is to provide a quantitative tool to analyze important parameters of the operation, in order to support some redefinitions in the operational procedure adopted by Petrobras. The main parameters are: the angle of the safe green-zone defined from the FPSO centerline, the installed DP power, the necessity of bow and stern offloading stations in the FPSO, among others.The results indicated that due to the large variation of wave-wind conditions along the year, both offloading stations are indeed necessary, since the ST can avoid the conditions in which it is pushed towards the FPSO. The results also indicated that incrementing the angle that defines the green-zone substantially decreases the offloading downtime. However, such decision also depends on a comprehensive risk analysis, since in that case the ST may be kept in a perpendicular position related to the FPSO. The risk analysis is beyond the scope of the present work. The DP power specified for the ST generations 2 and 3 are shown to be quite adequate, since it is demonstrated that increasing this power will not lead to a substantial reduction in the downtime.Copyright © 2013 by ASME
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Development of an Innovative Real-Time Simulator for DP-Shuttle Tanker / FPSO Offshore Connection Operation
Volume 1: Offshore Technology, 2012Co-Authors: Eduardo A. Tannuri, Carlos H. Fucatu, Humberto S. Makiyama, Felipe Rateiro, Denis Taniguchi, Isaias Quaresma MasettiAbstract:This paper discusses the prerequisites and the technical aspects of an innovative real-time simulator for DP-Shuttle Tanker and FPSO offshore connection operation. This simulator was developed by means of a partnership between the University of Sao Paulo and Petrobras. The software is based on the TPN (Numerical Offshore Tank) numerical code which had several modifications, in order perform real-time simulations. The mathematical models considered in the simulator and the computer architecture (hardware and software) will be presented.Copyright © 2012 by ASME
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development of an innovative real time simulator for dp Shuttle Tanker fpso offshore connection operation
ASME 2012 31st International Conference on Ocean Offshore and Arctic Engineering, 2012Co-Authors: Eduardo A. Tannuri, Carlos H. Fucatu, Humberto S. Makiyama, Felipe Rateiro, Denis Taniguchi, Isaias Quaresma MasettiAbstract:This paper discusses the prerequisites and the technical aspects of an innovative real-time simulator for DP-Shuttle Tanker and FPSO offshore connection operation. This simulator was developed by means of a partnership between the University of Sao Paulo and Petrobras. The software is based on the TPN (Numerical Offshore Tank) numerical code which had several modifications, in order perform real-time simulations. The mathematical models considered in the simulator and the computer architecture (hardware and software) will be presented.Copyright © 2012 by ASME
Haibo Chen - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Oil Spill Risk in DP Shuttle Tanker Direct Offloading Operations
Volume 2: Structures Safety and Reliability, 2011Co-Authors: Haibo Chen, Torgeir Moan, Arve Lerstad, Ka˚re BreivikAbstract:DP Shuttle Tankers performing offloading directly from fixed or geostationary floating offshore installations is addressed in this paper. It is important to ensure that disconnection of offloading hose can be achieved in time given Shuttle Tanker DP failure and position loss. The accident scenario is the hose fail-to-disconnect while Shuttle Tanker has an excessive position excursion. The consequence can be oil spill combined with the damage the offloading system. The spill amount can be as much as the crude oil volume in the hose, or over 1000 m3 if isolation and shutdown of oil export pump on the installation are not achieved timely. Various barriers to prevent oil spill have been developed over the past 30 years’ history of Shuttle Tanker offshore loading. However, the direct offloading is a new operational context to the traditional offloading. A quantitative frequency model for oil spill initiated by DP Shuttle Tanker position loss in direct offloading is presented in this paper. Case study results show that in the base case where only traditional barriers are used, the frequency for large oil spill up to 1000 m3 or more may reach 2.48E−03 per year, given 20 hours offloading cargo transfer time and 52 times offloadings per year. This frequency is not negligible, and risk reduction measures are viewed necessary. Novel safety barriers, i.e. Automatic Shutdown and Release (ASDR), as well as the HPR (Hydroacoustic Position Reference) and BLS (Bow Loading System) weak link mode, are analyzed as sensitivity cases. Results show that the frequency of large oil spill can then be reduced to 3.81E−05 per year, i.e. 1.5% of the base case value, and this is well within 1.0E−04 per year level. Recommendations to minimize oil spill risk during DP Shuttle Tanker direct offloading operations are proposed in this paper.Copyright © 2011 by ASME
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Probabilistic Evaluation of Collision Between DP Shuttle Tanker and Geostationary FPSO in Direct Offloading
29th International Conference on Ocean Offshore and Arctic Engineering: Volume 2, 2010Co-Authors: Haibo Chen, Arve Lerstad, Torgeir MoanAbstract:A geostationary FPSO does not weathervane like a turret-moored ship-shaped FPSO. The offshore industry has limited experience for direct offloading from such geostationary installations in the North Sea. In recent years direct offloading operations from geostationary FPSOs by DP Shuttle Tankers, have been developed, and key operational principles for such a system are presented in this paper. Probabilistic modeling of the collision risk between Shuttle Tanker and geostationary FPSO in direct offloading is presented, followed by a case study. It is found that the collision risk level is much lower in the direct offloading than in the tandem offloading. The results demonstrate that the direct offloading approach is a promising concept with inherent safety designed in the operations, i.e. the positioning philosophy of the Shuttle Tanker and a large separation distance.© 2010 ASME
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FPSO-Shuttle Tanker Collision Risk Reduction
Journal of Offshore Mechanics and Arctic Engineering-transactions of The Asme, 2005Co-Authors: Haibo Chen, Torgeir MoanAbstract:To reduce the occurrence of Tanker drive-off, and to reduce the probability of recovery failure should drive-off happen, are two basic principles to reduce FPSO and DP Shuttle Tanker collision in tandem offloading. In this paper we focus on measures to reduce recovery failure. Previous analyses revealed that recovery failure probability is high due to a lack of time for the DP operator to initiate the recovery action in a Tanker drive-off scenario. To increase the time window and to reduce the operator reaction time are therefore two main principles of recovery failure reduction. A substantial increase of the separation distance between FPSO and the Tanker, and a possible reduction of the main propeller(s) forward thrust that can be used by the Tanker DP system are two measures to increase the time window. The effective reduction of operator reaction time can be achieved by a number of measures, i.e., selection, training, procedure, crew resource management, and automation support, which are designed to improve early detection as well as effectively reduce the DP operator’s time in diagnosis and situation awareness.
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probabilistic modeling and evaluation of collision between Shuttle Tanker and fpso in tandem offloading
Reliability Engineering & System Safety, 2004Co-Authors: Haibo Chen, Torgeir MoanAbstract:Abstract DP Shuttle Tanker drive-off in tandem offloading poses a threat of collision to Floating Production, Storage, and Offloading unit (FPSO) with potential serious consequences. A two-stage probabilistic model of FPSO and Tanker collision in the tandem offloading operation is developed. The first part of analyses based on this model deals with Tanker drive-off scenarios. Findings reveal that the Tanker drive-off frequency in tandem offloading is high. Based on analyses of incidents, failure prone situations, termed as excessive surging and yawing, under which Tanker drive-off frequently happened, are identified. Measures to eliminate excessive surging and yawing, which ultimately reduce Tanker drive-off occurrence, are proposed. The second part of analyses deals with recovery action initiated by Tanker DP operator in drive-off scenario. Given the favored recovery strategy by the majority of operators, analyses revealed that recovery failure probability is still high due to lack of time for DP operator to initiate the recovery action in Tanker drive-off scenario. Measures to increase available time, and to reduce operator reaction time, are proposed to reduce the recovery failure.
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Prediction of Relative Motion and Probability of Contact Between FPSO and Shuttle Tanker in Tandem Offloading Operation
Journal of Offshore Mechanics and Arctic Engineering-transactions of The Asme, 2003Co-Authors: Haibo Chen, Torgeir Moan, Sverre Haver, Kjell LarsenAbstract:Excessive relative motions between Floating Production Storage Offloading Unit (FPSO), and Tanker, which are termed as excessive surging and yawing events, are identified as the “failure prone situation” in tandem offloading. These events have contributed to the initiation of Tanker drive-off in most collision incidents that happened in the North Sea in recent years. To estimate and reduce the probability of excessive surging and yawing events in tandem offloading, a simulation-based approach, which is based on a state-of-the-art time-domain simulation code SIMO, is presented in this paper. A typical North Sea FPSO and a DP Shuttle Tanker simulation models are setup in SIMO and calibrated by full-scale measurements. The simulated relative distance and relative heading between FPSO and Tanker are analyzed by fitting their extreme values into statistical models which give out probabilities of excessive surging and yawing events. Sensitivity studies are performed to pinpoint contributions from various technical and operational factors. Measures to minimize the occurrence of excessive surging and yawing events are identified in design and operational perspectives.
Isaias Quaresma Masetti - One of the best experts on this subject based on the ideXlab platform.
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FPSO AND MONOBUOY OFFLOADING OPERATION WITH A CONVENTIONAL Shuttle Tanker: DIMENSIONING OF TUGBOAT BASED ON NUMERICAL SIMULATION
IFAC Proceedings Volumes, 2016Co-Authors: Eduardo A. Tannuri, Fernando Gomes Da Silva Torres, Haroldo Igreja, Isaias Quaresma MasettiAbstract:Abstract In the present paper, a numerical simulation analysis of FPSO and monobuoy tug-assisted offloading operation is carried out. The main objective is to define the required tug-force that must be applied in the Shuttle Tanker in order to guarantee a safe operation. Critical environmental conditions of Brazilian waters are used, and a full time domain computational simulator is used to estimate vessels motions and hawser forces during the operation. Operational criteria adopted by Petrobras were then used to verify the risks associated to each operation. Such procedure was used to define the minimum requirements for the offloading assistance tugboats.
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Development of an Innovative Real-Time Simulator for DP-Shuttle Tanker / FPSO Offshore Connection Operation
Volume 1: Offshore Technology, 2012Co-Authors: Eduardo A. Tannuri, Carlos H. Fucatu, Humberto S. Makiyama, Felipe Rateiro, Denis Taniguchi, Isaias Quaresma MasettiAbstract:This paper discusses the prerequisites and the technical aspects of an innovative real-time simulator for DP-Shuttle Tanker and FPSO offshore connection operation. This simulator was developed by means of a partnership between the University of Sao Paulo and Petrobras. The software is based on the TPN (Numerical Offshore Tank) numerical code which had several modifications, in order perform real-time simulations. The mathematical models considered in the simulator and the computer architecture (hardware and software) will be presented.Copyright © 2012 by ASME
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development of an innovative real time simulator for dp Shuttle Tanker fpso offshore connection operation
ASME 2012 31st International Conference on Ocean Offshore and Arctic Engineering, 2012Co-Authors: Eduardo A. Tannuri, Carlos H. Fucatu, Humberto S. Makiyama, Felipe Rateiro, Denis Taniguchi, Isaias Quaresma MasettiAbstract:This paper discusses the prerequisites and the technical aspects of an innovative real-time simulator for DP-Shuttle Tanker and FPSO offshore connection operation. This simulator was developed by means of a partnership between the University of Sao Paulo and Petrobras. The software is based on the TPN (Numerical Offshore Tank) numerical code which had several modifications, in order perform real-time simulations. The mathematical models considered in the simulator and the computer architecture (hardware and software) will be presented.Copyright © 2012 by ASME
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Analysis of Oil Transfer Lines for Offshore Terminals With Controlled Buoyancy
Volume 3: Pipeline and Riser Technology; Ocean Space Utilization, 2008Co-Authors: Ana Paula Dos Santos Costa, Sergio H. Sphaier, K. Nishimoto, Isaias Quaresma MasettiAbstract:This paper presents a study on the design and dynamic behavior of hose lines for offshore oil transfer. Moreover, a new configuration of floating hose line that minimizes the dynamic effect in the connections of the line of oil transfer to the Offshore Terminal and to the Shuttle Tanker is analyzed. This conception reduces the damages in the elements of the extremity due to the great accelerations and the small bending radius, which the structure of the hoses is submitted. Although the benefits of the present configuration are applied for abandoning and stowing conditions and a complete set of numerical analysis and model tests were performed, only the results for the offloading operation were presented.© 2008 ASME
Rupert Hallmann - One of the best experts on this subject based on the ideXlab platform.
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thruster interaction effects on a dp Shuttle Tanker wake flow measurements of the main propeller and bow tunnel thrusters
ASME 2014 33rd International Conference on Ocean Offshore and Arctic Engineering, 2014Co-Authors: J. L. Cozijn, Rupert HallmannAbstract:This paper discusses thruster interaction effects for a DP Shuttle Tanker, equipped with two main propellers and rudders, as well as two bow tunnel thrusters. Thruster-interaction model tests were carried out in MARIN’s Deepwater Towing Tank. Detailed PIV measurements were taken of the wake flow behind the main propellers and rudders. Furthermore, PIV measurements were taken of the wake flow of one of the two bow tunnel thrusters. The flow velocities were measured in a large number of cross sections at different down-stream positions. The PIV measurements provide a detailed image of the velocities in the thruster wake, showing axial velocities, as well as transverse and vertical velocity components.The results of the first set of measurements showed in detail the wake flow behind the main propeller of the DP Shuttle Tanker. The wake flow pattern was determined at rudder angles of 0 deg and 10 deg. Since the research is related to DP performance, bollard pull conditions (zero forward speed) were considered in the model tests.The results of the second set of measurements showed in detail the wake flow of one of the bow tunnel thrusters. The wake flow pattern was investigated in zero speed conditions, as well as for the vessel at forward speed. The observed flow patterns helped to explain the reduced bow tunnel performance at forward speed.The results of the present research are used to further improve the understanding of the physics of thruster interaction effects. Furthermore, the results will serve as validation material for CFD calculations that are currently being performed.© 2014 ASME