Horizontal motions of a tanker single point moored in current, wind, and waves were numerically investigated under four alternative configurations, namely, buoy mooring (SBM), articulated tower mooring (ATM), bow turret mooring (BTM), and internal turret mooring (ITM). The analysis was based on a previously validated, comprehensive mathematical model of the equations of motion in three degrees of freedom (surge, sway, and yaw) that considers five sets of forces: 1) nonlinear quasi-steady hydrodynamic response and control forces; 2) linear memory effects due to radiated waves; 3) nonlinear mooring restoring force characteristics; 4) empirical wind actions; and 5) first-order wave forces and wave drift forces. Locally linearized stability analyses showed that restoring characteristics have no influence on static bifurcations (typical for BTM and ITM) and only minor influence on dynamic bifurcations (typical for SBM and ATM). However, nonlinear time domain simulations revealed that they do affect the form of asymptotic motion trajectories as well as line tension amplitudes. It was found that turret position is a significant parameter and motion behavior is sensitive to the direction of wind and waves relative to current. Comparison of simulated time histories between autonomous and nonautonomous modes indicated that the traditional spectral analysis treating high-frequency and low-frequency responses separately may not be valid for locally unstable cases.

Issue Section:
Research Papers
Topics:
Mooring, Scanning probe microscopy, Tankers, Waves, Wind, Bifurcation, Buoys, Degrees of freedom, Emission spectroscopy, Equations of motion, Simulation, Spectroscopy, Stability, Surges, Tension, Wave drift forces, Wave forces, Yaw
1.
Bernitsas
 
M. M.
, and
Papoulias
 
F. A.
,
1986
, “
Stability of Single Point Mooring Systems
,”
Journal of Applied Ocean Research
, Vol.
8
, No.
1
, pp.
49
–
58
.
2.
Faltinsen, O. M., Kjaerland, O., Liapis, N., and Walderhang, H., 1979, “Hydrodynamic Analysis of Tankers at Single-Point-Mooring Systems,” Second International Conference on Behaviour of Offshore Structures, London, U.K., Paper No.59, pp. 177–206.
3.
Jiang, T., 1991, “Investigation of Nonlinear Ship Dynamics Involving Instability and Chaos in Examples from Offshore Technology,” Ph.D. thesis, The University of Hamburg, IfS-Report No. 512 (in German).
4.
Jiang, T., Schellin, T. E., and Sharma, S. D., 1987, “Maneuvering Simulation of a Tanker Moored in a Steady Current Including Hydrodynamic Memory Effects and Stability Analysis,” Proceedings of the International Conference on Ship Manoeuvrability, Royal Institution of Naval Architects, London, U.K., Vol. 1, Paper No. 25.
5.
Jiang, T., and Schellin, T. E., 1988a, “Motion Prediction of a Single Point Moored Tanker Subjected to Current, Wind and Waves,” Proceedings of the 7th International Symposium on Offshore Mechanics and Arctic Engineering, Houston, TX, Vol. 2, ASME, pp. 317–326.
6.
Jiang, T., and Sharma, S. D., 1992, “Investigation of Horizontal Motions of an SPM tanker in Shallow Water through Computation and Model Experiment,” Proceedings of the 19th Symposium on Naval Hydrodynamics, Seoul, Korea.
7.
Oltmann, P., and Sharma, S. D., 1984, “Simulation of Combined Engine and Rudder Maneuvers Using an Improved Model of Hull-Propeller-Rudder Interactions,” Proceedings of the 15th Symposium on Naval Hydrodynamics, Hamburg, Germany, pp. 83–108.
8.
O’Donoghue
 
T.
, and
Linfoof
 
B. T.
,
1992
, “
An Experimental Study of Turret-Moored Floating Production Systems
,”
Journal of Applied Ocean Research
, Vol.
14
, pp.
127
–
139
.
9.
Schellin
 
T. E.
,
Jiang
 
T.
, and
Sharma
 
S. D.
,
1990
, “
Motion Simulation and Dynamic Stability of an Anchored Tanker Subject to Current, Wind and Waves
,”
Journal of Ship Technology Research (Schiffstechnik)
, Vol.
37
, No.
2
, pp.
64
–
84
.
10.
Sharma, S. D., Jiang, T., and Schellin, T. E., 1988b, “Dynamic Instability and Chaotic Motions of a Single-Point-Moored Tanker,” Proceedings of the 17th Symposium on Naval Hydrodynamics, The Hague, pp. 543–563.
11.
Shibuta, K., Nakagawa, K., Obokata, J., Higashida, Y., and Iwahashi, Y., 1989, “Experimental and Theoretical Study on Turret Mooring System for Large FPSO,” Proceedings of the 8th International Symposium on Offshore Mechanics and Arctic Engineering, The Hague, ASME, pp. 67–74.
12.
Tein, Y. S. D., Chantrel, J. M., Marol, E. M. H., and Huang, K., 1987, “A Rational Dynamic Analysis Procedure for Turret Mooring Systems,” Proceedings of the 19th Annual OTC Conference, Houston, TX, ASME, OTC 5527.
13.
Wichers, J. E. W., 1988, “A Simulation Model for a Single Point Moored Tanker,” Maritime Research Institute Netherlands, Wageningen, Publication No.797.
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