What is amazing to me is that a small collision damage (indent, ripping apart) generally above waterline and bulkhead deck, i.e. in the thin plate (6-4 mm) superstructure and deck house caused up-flooding of one compartment - a generator room - and that then, after Black Out - another five (!) compartments were slowly, progressively flooded through openings in the watertight bulkheads and that no bilge pumps were used to pump out the water.
The main and weather decks, even if thin plates too, also act as a strong horizontal fender to protect the bulkheads below in the hull in collisions. It will be interesting to see the actual damages, when the wreck is removed and put on a barge, to establish how the main/weather decks and the hull below waterline were damaged.
With free water on top of the (intact) double bottom in five or more compartments I would expect complete loss of stability, resulting, not in slow sinking, but in sudden capsize. As it didn’t happen, maybe something else happened.
Anyway, turning port just in front of M/T Sola TS allowing the anchor of the tanker to rip open the Helge Ingstad deck house side was stupid. I assume nobody on the warship really cared.
Helge Ingstad and Lines of Defense