According to a Radio Times interview with Larry Lamb, one of the key actors died on the way to the airport to tape his scenes. The whole series had to be rewritten because of it.
The series was recorded and edited almost entirely on location on board the ferries, using light-weight hand-held video cameras and recorders which were new technology at the time. However various technical problems were experienced: the rolling of the ship affected the head-speed/tracking servos of the video recorders, causing loss of picture synchronisation at times, and the cameras did not cope well with the high contrast between cabin interiors and the view out of the windows.
Kate O'Mara died on March 30th 2014 she was 74.
Michael Craig and Larry Lamb were the only cast members to appear in all 78 episodes of Triangle. Kate O'Mara departed in season two episode one.
The actor who played Katherine 'Kate' Laker's father died on the way to the airport to tape some scenes. The first season had to be rewritten because of it.