"...Helge Ingstad believed the vessel calling them to be one of the oncoming vessels they were tracking on radar. Assuming the tanker, slow moving and with its

"...Helge Ingstad believed the vessel calling them to be one of the oncoming vessels they were tracking on radar. Assuming the tanker, slow moving and with its bright deck lights obscuring its navigation lights, to be part of the shore installation,...": https://en.m.wikipedia.org/wiki/HNoMS_Helge_Ingstad_(F313) https://en.m.wikipedia.org/wiki/HNoMS_Helge_Ingstad_(F313)