The Waiting Game
Weather delays aren't just schedule problems. They're structural damage events.
A partially erected tower sits naked in the ocean, swaying aimlessly for days. Nobody is measuring the accumulated fatigue.
The Invisible Problem
Fatigue Accumulation
Vortex shedding creates thousands of stress cycles per hour. Each cycle consumes a fraction of the tower's 25-year design life—before the turbine ever spins.
The Impossible Question
Installation engineers face: "Is it still safe to finish installing?" Visual inspection can't answer this. Right now, they're guessing.
Economic Risk
Average tower value: $9.5M. If structural damage is discovered post-installation, the options are expensive: emergency inspection, derating, or replacement.
Weather Window Anxiety
Every delay day costs €50K+ (vessel standby, crew). But rushing to complete installation on a fatigued tower creates liability risk.
- VIV lock-in can occur at moderate wind speeds (10-18 m/s)
- Typical offshore delay: 72 hours (some extend to weeks)
- Freestanding tower has <0.3% structural damping (vs. 5-8% when RNA installed)
- One prolonged VIV event can consume 10-50% of bolt fatigue life before turbine ever spins
Forensic Incident Timeline
Construction phase failures reveal VIV as a silent threat. Three documented cases demonstrate the catastrophic consequences of undetected lock-in.
Lemnhult, Sweden
Vestas V112-3.0 MW collapsed during pre-commissioning. Bolts torqued in wet conditions; friction coefficient altered, causing massive scatter in preload. VIV caused flange gapping; bolts failed in bending fatigue within hours. Total collapse.
Germany
Tower buckled at 15m height. Blade imbalance created oscillations mimicking VIV. Plastic hinge formed at shell thickness transition. GMNIA analysis showed 40% buckling capacity reduction due to manufacturing imperfections.
Offshore Monopile VIV
"Waiting on Weather" fatigue accumulation. Monopiles left freestanding for months consumed 10-15% of fatigue budget before turbine operation began. No collapse, but asset started life degraded.
In every case, the failure mode was invisible until damage had accumulated. Visual inspection cannot detect VIV lock-in or quantify fatigue consumption.