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# Deformation effects

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The deformation of a vessel by its load, and that of positioning piles by temperature have consequences for the accuracy of the survey. This presentation by Erich Gaickhorst (GeoVisie) shows how.

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### Deformation effects

1. 1. Deformation effects on vessels The effects of flexibility on calibrations HSB Workshop Vessel Geometry and Calibrations 15 January 2014 Erich Gaikhorst The effects of flexibility on calibrations
2. 2. Index • Two examples • Fallpipe vessels – Flexibility – Temperature The effects of flexibility on calibrations
3. 3. Remaining error after calibration Offset Survey Noise (Quality offset survey) Sensor Noise (Quality sensor) Sensor Drift (Quality sensor) Calibration Noise (Quality calibration survey) Vessel Deformations(Load/Sea state/temperature/design) + Remaining error The effects of flexibility on calibrations
4. 4. Example 1: Flexibility • • • • High accurate sensors Offsets with mm accuracy Angles with 0.01° accuracy Correct calibrations • Position jumps (xy) of the ROV • Why The effects of flexibility on calibrations
5. 5. The effects of flexibility on calibrations
6. 6. The effects of flexibility on calibrations
7. 7. Loaded Empty The effects of flexibility on calibrations
8. 8. 60.000 Top view Surveyed Fwd 50.000 • Points SB and PS 40.000 30.000 20.000 PS Dock SB Dock 10.000 PS floating SB floating 0.000 -15.000 -10.000 -5.000 0.000 5.000 10.000 15.000 -10.000 -20.000 -30.000 Aft -40.000 The effects of flexibility on calibrations
9. 9. Difference between docked and floating 0.120 0.120 0.100 0.100 0.080 0.080 0.060 0.060 SB Series2 Best fit circle SB 0.040 0.020 0.040 Average angle (pitch err) between Sb and Ps: 0.13° 0.020 0.000 -40.000 -30.000 -20.000 -10.000 0.000 0.000 10.000 20.000 30.000 40.000 50.000 The effects of flexibility on calibrations 60.000 Best fit circle PS
10. 10. Example 2: Temperature • High accurate sensors • Offsets with mm accuracy • Angles with 0.01° accuracy • Placing tolerance gravel +/-35mm • Temperature a significant part of the error budget. • Height influenced by temperature The effects of flexibility on calibrations
11. 11. 65m The effects of flexibility on calibrations
12. 12. • Geometry December +5°C – Steel +5°C • First calibration May +23°C Steel +30°C;Water +25°C • Last calibration August +35°C Steel +60°C ;Water +27°C The effects of flexibility on calibrations
13. 13. 35m The effects of flexibility on calibrations
14. 14. coefficient of linear expansion Steel 1.20E-02 mm/°C Aluminium 2.30E-02 mm/°C temp [°] Steel Lenght [m] 0 5 10 15 20 25 30 35 40 45 50 55 60 65 5 10 15 20 25 30 35 40 45 50 55 60 65 70 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.3 3.6 3.9 4.2 0.6 1.2 1.8 2.4 3.0 3.6 4.2 4.8 5.4 6.0 6.6 7.2 7.8 8.4 0.9 1.8 2.7 3.6 4.5 5.4 6.3 7.2 8.1 9.0 9.9 10.8 11.7 12.6 1.2 2.4 3.6 4.8 6.0 7.2 8.4 9.6 10.8 12.0 13.2 14.4 15.6 16.8 1.5 3.0 4.5 6.0 7.5 9.0 10.5 12.0 13.5 15.0 16.5 18.0 19.5 21.0 1.8 3.6 5.4 7.2 9.0 10.8 12.6 14.4 16.2 18.0 19.8 21.6 23.4 25.2 2.1 4.2 6.3 8.4 10.5 12.6 14.7 16.8 18.9 21.0 23.1 25.2 27.3 29.4 2.4 4.8 7.2 9.6 12.0 14.4 16.8 19.2 21.6 24.0 26.4 28.8 31.2 33.6 2.7 5.4 8.1 10.8 13.5 16.2 18.9 21.6 24.3 27.0 29.7 32.4 35.1 37.8 3.0 6.0 9.0 12.0 15.0 18.0 21.0 24.0 27.0 30.0 33.0 36.0 39.0 42.0 3.3 6.6 9.9 13.2 16.5 19.8 23.1 26.4 29.7 33.0 36.3 39.6 42.9 46.2 3.6 7.2 10.8 14.4 18.0 21.6 25.2 28.8 32.4 36.0 39.6 43.2 46.8 50.4 3.9 7.8 11.7 15.6 19.5 23.4 27.3 31.2 35.1 39.0 42.9 46.8 50.7 54.6 The effects of flexibility on calibrations 5 10 15 20 25 30 35 40 45 50 55 60 65 65 m 3.9 7.8 11.7 15.6 19.5 23.4 27.3 31.2 35.1 39.0 42.9 46.8 50.7
15. 15. Thank you for your attention Questions? The effects of flexibility on calibrations