This is due to the uncertainties associated with snap loading after a slack lifting wire. The operational limit established in the time domain programs is based on the assumption that the maximum relative velocity between the crane tip and the waves represent a worst case scenario and that a slack lifting wire is not acceptable. Experience from the industry have shown that the method is unreasonable conservative, consequently leading to a restrictive operational Hs window.The main objective of this master thesis is to compare results obtained from the analytical calculations with results obtained from the time domain simulation programs Simulation of Marine Operations (SIMO) and OrcaFlex.

A maximum operational significant wave height, Hs, is determined using a proposed acceptance criteria. Available standards from DNV propose a systematic and analytical approach for estimating the hydrodynamic loads occurring in the splash zone. The majority of all offshore operations are performed using remotely operated vehicles (ROVs), where lifting through the splash zone is considered the most critical phase during launching and recovery of the ROV system. As a service company performing subsea operations, DeepOcean wishes to operate in the widest range of sea conditions.

Orcaflex thesis pdf