Offshore monopile installation campaigns frequently face delays due to environmental loads during dynamic lifting operations. This problem is especially acute in the lift-off phase, when the monopile is suspended and the vessel is exposed to wave-induced motion. The goal of this thesis is to investigate whether optimization of the rigging geometry can reduce such downtime by mitigating dynamic amplification effects.


A planar, linearized Lagrangian model was developed to simulate the dynamic response of the rigging system suspended from a vessel-mounted crane. The model includes multiple pendulum bodies and uses a frequency-domain formulation to calculate the transfer function from crane tip motion to resulting sideloads. This transfer function is used to compute the most probable maximum (MPM) sideloads across a range of sea states. A grid-based workability analysis links these loads to operational thresholds, and a numerical optimization was implemented to tune the rigging geometry for maximum uptime.


The analysis identified a dominant resonance near T_p = 8.16 s — the second natural mode of the suspended system — as the primary driver of limit exceedance. By modifying the lengths of the rigging elements, the natural frequencies could be shifted away from this critical range. The optimized configuration improved workability by 10–20 percentage points, depending on the metocean conditions.


Although the simplified model underestimates absolute load levels compared to a detailed OrcaFlex simulation, the relative response behavior is well captured. A conservative threshold correction was applied to enable consistent limit checking. The study shows that dynamic rigging optimization is a viable, low-effort strategy for reducing downtime in offshore monopile installation, and should be considered during project engineering.