N/A PSA Q&A LL with Wellesley

Songesand (35/4-2) – N/A

PSA: Q

Etter søknadens punkt 2.2 er det mange pockmarks i området. Skal noen av ankerlinene ligge over dem, og hvordan er dette i så fall håndtert i ankringsanalysene?

PSA: A

The Songesand regional seabed is covered by pockmarks of very limited depth and with very low slope gradients, see below maps of anchor spread overlaying maps of pockmarks and bathymetry. Whilst a maximum depth of 8 m was recorded on the site survey, the normal depression depth is typically less than 6 m. For the 8 anchor lines (from anchor to touchdown points) seabed depth variations are typically 2-3m, see bathymetry map below. Accordingly, mooring chains will be in constant contact with seabed and thus the seabed can be treated as flat for mooring analysis purposes.
The planned mooring spread will not be negatively impacted by the spread of pockmarks covering the region.
A check on the worst case ULS load was made. Line 8 will under the 100 year wave scenario have 640 m chain left on seabed which is beyond pockmarks.
[Figure]. Map of pockmarks (in light blue), anchor positions (circles) and the anchors spread.
[Figure] Bathymetry map overlaid by anchor spread