Model Summary |
 
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Model Summary |
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This example considers the tow-out and installation of a riser bundle. The riser bundle is 850m in length and is attached at both ends to tug vessels by 150m cables. The shallow water tow-out takes place in a water depth of 35m at a constant tow speed of 1.8m/s. An initial static analysis is first performed with the bundle restrained vertically to obtain an approximate starting configuration. The initial constraints are subsequently removed in a quasi-static analysis, and the riser bundle attains its floating position at the mean water line. A further quasi-static analysis is then performed where the forward tow speed is simulated by an in-line uniform current. Finally, regular wave loading is introduced in a dynamic analysis.
The deep water installation procedure takes place in a water depth of 875m. A 75t dead anchor weight is attached to front end of the riser bundle to facilitate the upending.
An initial static analysis with vertical constraints is again performed, and is again followed by a quasi-static analysis in which the riser bundle reaches its equilibrium position. Two dynamic analyses are then performed to reposition the riser bundle into a vertical configuration.