Shielding Effect for Workability Improvement in Offshore Lifting Operations

Abstract

This thesis explains the effect of wave shielding ability of a large vessel on the workability of offshore lifting operations. Monopile and jacket structures are considered for this study. The goal is to enhance the operational window and safety of these operations by analyzing in-depth how much effective is vessel shielding.

A detailed methodology is deveoped and employed including hydrostatic stability evaluation of vessel, sea keeping analysis in Ansys Aqwa, and time domain dynamic simulations in Orcaflex. Vessel, monopile, jacket, crane, and relevant sea states are modeled using Ansys Aqwa and Orcaflex to simulate reaslistic conditions in order to check their influence on actual lifting operations.

The results show that vessel sheilding significantly improves the offshore workability for specific wave directions and especially for lower wave periods. The effect of shielding on the type of structure to be installed also varies based on structure type. Workability enhances much more for monopile installation as compared to jacket installation if shielding is considered.

These findings highlight how important it is to take into account the designs of offshore structures when looking at the benefits of wave shielding. The study proves useful for making offshore lifting activities better, which could lower risks, cut downtime, and save costs. By allowing operations to continue in a wider range of weather conditions, shielding effect appears to be a good way to make offshore installation projects safer and cost friendly.