Offloading of VLCCs from a CALM buoy: A two-body approach to compute line tensions
- Elf Aquitaine Production, Pau (France). Offshore Structure Dept.
- Ecole Centrale, Nantes (France). Naval Hydrodynamics Lab.
ELF CONGO has recently instrumented a CALM buoy on its DJENO site, in order to monitor the line tension in the hawser during offloading of VLCC tankers. Environmental conditions and position of the tanker are recorded as well and provide a good data base. The very shallow water and the benign but noncolinear environmental conditions considered are responsible for tanker resonant motions. The system has been modeled numerically for calibration purposes. The buoy and hawser have been modeled by a single nonlinear spring. The tanker and tug vessel connected to it have been modeled in different ways, including a two-body approach. Nonlinear time domain simulations have been run to compute the mean position and slow drift of the tanker under waves, wind and current. Results of the analysis are presented and compared with on site measurements for several offloading conditions. Even though there are still some uncertainties, a two-body approach gives substantial improvements in the line tension and tanker motions computation.
- OSTI ID:
- 449706
- Report Number(s):
- CONF-9606279--; ISBN 0-7918-1490-4
- Country of Publication:
- United States
- Language:
- English
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