STATIONKEEPING DYNAMIC POSITIONING FOR YACHTS. Hans Cozijn

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1 STATIONKEEPING DYNAMIC POSITIONING FOR YACHTS Hans Cozijn Senior Project Manager Offshore

2 YACHTS VS. OFFSHORE INDUSTRY 2

3 YACHTS VS. OFFSHORE INDUSTRY Source : Source : 3

4 YACHTS VS. OFFSHORE INDUSTRY Source : 4

5 WHAT DOES THIS HAVE TO DO WITH YACHTS!? 5

6 PRESENTATION OUTLINE Dynamic Positioning Tools for DP Analysis Ongoing gresearch DP Challenges Typical for Yachts (How) Can MARIN Help You? Concluding Remarks 6

7 DYNAMIC POSITIONING BASIC PRINCIPLES Vessel Thrusters are Automatically Controlled to Keep the Vessel at the Required Postion and Heading Necessary Components : Position measurement Kalman filter Controller Allocation algorithm Thrusters Power DP Classes DP0 manual operation DP1 automatic, no redundancy DP2, DP3 increased redundancy 7

8 TOOLS FOR DP ANALYSIS Static DP Capability Calculations PRO : easy to compare cases CON : limited accuracy Time domain Simulations PRO : detailed results Increasing Accuracy CON : more time consuming Increasing Level of Detail DP Model Tests Increasing Complexity Increasing Cost PRO : most accurate prediction CON : relatively expensive Sea Trials PRO : "the real thing" CON : no control over environment 8

9 STATIC DP CAPABILITY CALCULATIONS Static calculations; Mean wind, wave and current forces Mean thruster forces Fixed current Wind wave relation No dynamic behaviour No stationkeeping accuracy Used in Early Design Stage Thruster configurations Failure cases Stationkeeping Capability Sustained wind speed, presented in polar plot ("footprint") 9

10 DP TIME DOMAIN SIMULATIONS Time domain Simulations Dynamic wind, wave and current forces Simulation of vessel behaviour in time Optimise DP control settings Workability analysis Accuracy of the Results depends on the Quality of the Simulation Model Simulation Results Statistics of vessel position Statistics of thruster loading Heading window for given sea state Fuel consumption position error heading window drift off max position error 1 2 heading [deg] 10

11 DP MODEL TESTS Model Tests Complete physical model + DP system Realistic thruster response Thruster interaction i effects Optimise DP control settings Safelyinvestigate limitseastates states Identify possible unexpected behaviour MostRealistic Design Verification Model Test Results Statistics ti ti of vessel position Statistics of thruster loading Heading window for given sea state Fuel consumption Calibration of numerical models 11

12 ONGOING RESEARCH Thruster interaction Effects PIV measurements CFD calculations Advanced Allocation Algorithms Fuel efficiency Stationkeeping accuracy Software Developments Identical DP system for model tests, simulations and bridge simulator Use of commercial DP systems in model tests and bridge simulator opendp JIP Software frame work for DP developments Support DP innovations Discussion, co operation and sharing 12

13 DP CHALLENGES TYPICAL FOR YACHTS Large Area above Water Line > Large Wind Loads Limitations in Thruster Lay out Main propulsion + bow tunnels Often no specific thrusters for DP Limitations in DP operation Shallow water, confined water,... Swimmers in the water Manual Control (joy stick) or DP1 DP is a "nice to have", not a critical capability Mostly for manoeuvring in port No redundancy (class notation DP0 / DP1, not DP2 / DP3) Other Hydrodynamic Questions that Require an Answer? 13

14 (HOW) CAN MARIN HELP YOU? Static DP Capability Analysis Thruster lay out Thruster sizing Time domain Simulations DP control settings Vessel motions + stationkeeping accuracy Fuel consumption DP Model Tests Same as time domain simulations, but more accurate results Demonstration joy stick control Bridge Simulator (?) DP + joy stick control demonstration / training 14

15 CONCLUDING REMARKS Yacht Design vs. Offshore Industry : Cultural Differences? Hydrodynamics are the Same for Everyone! Priorities : Comfort : noise and vibrations? Stationkeeping accuracy? Fuel consumption? Special Requirements : Heading control for vessels at anchor? Stationkeeping during embarking / disembarking? Special DP strategies : heading control to follow the sun? 15

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