Germany’s BSU report on the collision between the ro-ro ferry Schleswig-Holstein and the sailing yacht Mahdi in calm, clear conditions highlights the fact that at night navigation lights are effectively point-sources and they can deceive the unwary. Often, by the time someone realises that a collision is imminent it’s too late to react.
As the BSU analysis says: Looked at superficially, the collision was purely the result of inadequate monitoring of the sea-room as defined in
COLREG Rule 5 by the bridge crew of the Schleswig-Holstein and consequent non-observance of right of way by the ferry. However, such an assessment of the situation is most certainly too simplistic.