The capstan that had become brittle
For a film of this scale, Cameron used a lot of practical effects, and he made sure that many of the closeup shots will hold up well in the future as opposed to CGI. However, if you look closely, you’ll discover that it produced some very visible problems. Props were employed to replicate a capstan, which is a revolving cylinder used to wind ropes. When a passenger falls to the bottom of the deck, he is hit by one of these gigantic monsters. It was obviously impossible to make it out of metal, therefore it was fashioned of foam. However, this meant that once the wrinkle was hit, we could see it.