Question:

Is it possible to consider the hull deflections (forced displacement of topside module supports) for the spectral fatigue analysis?

Answer:

We do not have an analysis to consider the hull deflections, however, you can use joint deflections (PERSETS) as suggested below:
1. Use joint PERSETS with the Tow OCI file, but you would need to know the displacement RAOs for the modules and apply the correct PERSETS to each load condition manually.
2. Alternatively, if you don't think that the joint displacements and Tow motions are dependent upon each other, you can perform two separate fatigue analyses and combine the damage.