I remember being shown this video on my first NBCD 5 course at the 'old' PHEONIX (Matapan Road). There was a Canadian 2 1/2 instructor there who had been on PRESERVER at the time. I claim no great accuracy or credibility, but seem to recall that the above 2 posts are correct in that there was an error in relaying or repeating telegraph orders that ended up with a full ahead being given when it wasn't required. Interaction of the 2 ships pressure waves took care of dragging PENELOPE around the bow.
For any of you budding Warfare Officers on this site who are spending so much time reading you Rule of the Road books, watch this clip carefully. When you are taught that when things go pear shaped in a RAS you never try to drive out ahead you now know why.