System integration from single unit thrust to total

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System integration: from single unit thrust to total vessel DPperformance Norbert Bulten Product Performance

System integration: from single unit thrust to total vessel DPperformance Norbert Bulten Product Performance Manager Wärtsilä 1 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten

CONTENTS Contents • Introduction: DP-capability tool • Single thruster unit performance • Environmental forces

CONTENTS Contents • Introduction: DP-capability tool • Single thruster unit performance • Environmental forces • Thrust Allocation Logic (TAL) • Verification of DP results • Application to drill rig • Conclusions 2 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten

INTRODUCTION Total vessel DP performance • Total vessel DP-performance based on: • Total generated

INTRODUCTION Total vessel DP performance • Total vessel DP-performance based on: • Total generated vessel thrust, based on actual 360° unit performance data • Balance with environmental forces 3 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten

INTRODUCTION Aim of the new development “Make the transition from Thrust-Availability polar plots to

INTRODUCTION Aim of the new development “Make the transition from Thrust-Availability polar plots to DP-capability plots” Maxim wind- um speed Thrus utiliza ttion 4 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten

INTRODUCTION Balancing forces & moments • Balance the environmental forces and moment with the

INTRODUCTION Balancing forces & moments • Balance the environmental forces and moment with the actual thrust forces from all thrusters (including thruster-hull interaction losses and forbidden zones) 5 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten

INTRODUCTION Thrust Allocation Logic T 1 T 4 • Thrust Allocation Logic (TAL) is

INTRODUCTION Thrust Allocation Logic T 1 T 4 • Thrust Allocation Logic (TAL) is the conductor of all thruster units in operation. T 2 T 5 T 6 T 3 • TAL determines: • Thruster loading (%) • Thruster azimuth angle T 1 T 4 T 5 • Resultant force and moment of all units together have to balance the environmental forces and moments. 6 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten T 2 T 6 T 3 L TA

INTRODUCTION Main building blocks of DP-capability calculation method • Main building blocks to be

INTRODUCTION Main building blocks of DP-capability calculation method • Main building blocks to be implemented or developed: • Single full-scale thruster performance (including thruster hull interaction losses and forbidden zones) • Environmental forces & moments • Thrust Allocation Logic • Verification & application example review 7 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten

FULL SCALE THRUSTER PERFORMANCE Single thruster unit performance determination • Hydrodynamic performance determination of

FULL SCALE THRUSTER PERFORMANCE Single thruster unit performance determination • Hydrodynamic performance determination of the thruster based on full scale CFD simulations • Single ‘free hanging’ unit • Unit under a flat plate 8 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten

FULL SCALE THRUSTER PERFORMANCE Thruster performance in actual operation • Thruster performance evaluation of

FULL SCALE THRUSTER PERFORMANCE Thruster performance in actual operation • Thruster performance evaluation of drill-rig with 8 steerable thrusters in transit operation. • Monitoring data has been made available for all 8 thrusters in transit speed: • Propeller RPM • Azimuth angle • Hull resistance and thruster open water performance based on CFD. 9 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten

FULL SCALE THRUSTER PERFORMANCE Full scale trials with semi-submersible rig • Based on open

FULL SCALE THRUSTER PERFORMANCE Full scale trials with semi-submersible rig • Based on open water thruster performance data and operating conditions, the vessel speed is calculated. Propeller RPM as function of time (thrusters 1, 4 and 8) 1 D-system simulation model of drill-rig with 8 steerable thrusters 10 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten

FULL SCALE THRUSTER PERFORMANCE Full scale trials with semi-submersible rig Propeller torque as function

FULL SCALE THRUSTER PERFORMANCE Full scale trials with semi-submersible rig Propeller torque as function of time • Power absorption of individual thruster units match well with measurements. • Overall ship speed and acceleration is predicted well. Ship speed as function of time 11 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten

ENVIRONMENTAL FORCES Environmental forces • Forces on the vessel come from: • wind •

ENVIRONMENTAL FORCES Environmental forces • Forces on the vessel come from: • wind • waves • current • Wind and current drag forces often based on relative simple calculation methods. 12 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten

ENVIRONMENTAL FORCES Environmental forces • Current forces based on beam, draft and a single

ENVIRONMENTAL FORCES Environmental forces • Current forces based on beam, draft and a single dragcoefficient are still seen in industry. • These simple estimations should be replaced by full scale CFD simulations of the actual vessel geometry to get more accurate input for DP-capability calculations. 13 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten

ENVIRONMENTAL FORCES Mzenvironment Balancing forces & moments • Horizontal forces • longitudinal and lateral

ENVIRONMENTAL FORCES Mzenvironment Balancing forces & moments • Horizontal forces • longitudinal and lateral forces, combined into 1 vector (magnitude & direction) • Moments • Vessel yaw-moment 14 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten Fenvironment

TAL Thrust Allocation Logic (TAL) • Outcome of Thrust Allocation • Assigned power rating

TAL Thrust Allocation Logic (TAL) • Outcome of Thrust Allocation • Assigned power rating / thruster unit • Azimuth angle / thruster unit • Drill-rig with 8 thrusters has 16 degrees of freedom difficult to calculate, but easy to check! • Thrust Allocation is valid when yaw moment and forces are balanced 15 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten

VERIFICATION Verification of DP-capability • DP-capability calculation for drill ship • Comparison with DNVGL

VERIFICATION Verification of DP-capability • DP-capability calculation for drill ship • Comparison with DNVGL web-app • All units intact • Power reserve margin 10% • Dynamic factors 25% • Unit thrust identical to DNVGL • Same output for both calculation methodologies 16 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten 5 6 7 11 10 9 8 6 8

VERIFICATION T 2 Verification of DP-capability T 3 T 1 • DP-capability calculation for

VERIFICATION T 2 Verification of DP-capability T 3 T 1 • DP-capability calculation for drill ship T 3 • Evaluation of generated thrust per unit shows: • Load or thrust ratio • Forbidden zones T 6 T 4 T 6 T 5 17 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten T 5

APPLICATION DP-capability for drill-rig • DP-capability calculation for DNVGL scale 11 • All units

APPLICATION DP-capability for drill-rig • DP-capability calculation for DNVGL scale 11 • All units in operation • Drill-rig with 8 thrusters @ 6500 k. W • 8°-tilted-thruster Wärtsilä units • 5°-tilted nozzle reference units 18 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten

APPLICATION DP-capability for drill-rig • DP-capability calculation for DNVGL scale 11 • Single unit

APPLICATION DP-capability for drill-rig • DP-capability calculation for DNVGL scale 11 • Single unit failure (unit 1 solid line, unit 2 dotted line) • Drill-rig with 8 thrusters @ 6500 k. W • 8°-tilted-thruster Wärtsilä units • 5°-tilted nozzle reference units 19 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten

CONCLUSIONS Conclusions • New DP-capability calculation tool has been developed and verified. • True

CONCLUSIONS Conclusions • New DP-capability calculation tool has been developed and verified. • True thruster performance based on 360° circumference is utilized in the calculation algorithm. • Outcome of the calculation tool is according expectations and in agreement with existing methodologies. • Benefits of 8° tilted thrusters can be quantified better with the new calculation tool, based on 360° input data tables for thruster performance. • Critical review of environmental forces calculation methods have revealed weaknesses, which can be improved with utilization of full scale CFD simulations. 20 © Wärtsilä PUBLIC 16. 10. 2019 MTS - DP-conference 2019 / Thrusters / Norbert Bulten