Model tests of a stiffness-similar jack-up, Part 3: Transit condition and uncertainty analysis

Abstract

This Part 3 of the paper series on jack-up model tests describes the model test design and selected results for transit conditions. As part of the summary for the paper series, uncertainty analysis for the entire jack-up model tests was also conducted and presented. Operating scenarios were simulated, covering jack-up model with legs extended above the hull as well as legs partially submerged into the water. Soft moorings were used to provide horizontal restraint onto the jack-up model. Long-crested waves without and with co-linear uniform current were used throughout the tests, with current meant to simulate sea-keeping and wet towing conditions. Reduced motions in surge and pitch were observed for the jack-up with legs partially submerged into the water, demonstrating additional damping to be gained, but at the expense of increased towing drag forces. Additional measurements in terms of bending moment at the leg-to-hull connection as well as shear forces on the starboard leg were also compared. Uncertainty analysis was conducted for the entire jack-up model test to quantify the errors and confidence level of the presented results.