When the incoming tide is washing against Helen, her hair is soaked and in the next shot her hair is styled then soaked again .
After Bobby makes coffee and takes the pot and cup to his father, in one scene he's holding the pot with one hand and in other scenes with both hands.
"The Mexican word for rope is 'cuerda," Doug says to Helen. Of course, "Mexican" is not a language; the correct word would have been "Spanish."
Also when Bobby is holding the coffee pot he is holding the bottom of the hot pot with his hand.
When Barbara Stanwyck is driving for help, the front view shows a driver with a hat on. The side view shows Barbara.
After the dad goes out on the pier to get his son he moves Bobbys foot practically out of the gap and then says "its stuck it wont move"