In the movie in rough weather Jessica is seen strapped to the bunk . Yachts do not use this system, they all use lee cloths . Which you see on the real boat at the end of the movie with real footage from the boat . Hint its red.
After dismasting, when Jessica comes up, shrouds can be seen intact behind her back. Shrouds cannot stay tensioned after the top of the mast gives way.
When young Jessica first secures Ben's boat and asks "is that acceptable" she twists the rope for the last locking loop the wrong way, making a less secure hitch.