Multiple failures likely preceded Tjörn boat collision, expert says

A collision between a Norwegian cargo ship and a small leisure boat off Tjörn on Tuesday evening likely resulted from repeated failures, according to a maritime safety expert.

Mats Gruvefeldt, head of unit at Chalmers Maritime Academy, told Swedish broadcaster SVT that such accidents do not occur without multiple, consistent errors.

The incident took place around 22:00 in darkness and rain. Witnesses on a nearby leisure boat reported that the smaller vessel, a snipa, had collided with the 90-metre Norwegian cargo ship and subsequently sank. One woman was confirmed dead at the scene, while her daughter remains missing. A father and son were rescued from the water.

The cargo ship’s captain reported no awareness of the collision, which Gruvefeldt said is not unusual given the size disparity between the vessels.

Maritime rules require vessels to maintain a lookout and use navigation lights in poor visibility, he noted. While cargo ships have radar and Automatic Identification System (AIS) to track other vessels, leisure boats often lack such equipment. Rain can also interfere with radar, potentially obscuring smaller craft.

Gruvefeldt added that leisure boat operators frequently underestimate the speed of larger vessels, misjudging safe crossing distances.