Continuity mistake: Just as Quint shouts, "You may be a big yahoo in the lab, but out here you're just supercargo..." and when he asks Brody to unbuckle him, the cleat at the stern has plenty of line wound round it and there is a red cup beside it. However, in the previous and following consecutive shots within this scene, there is no line and no cup. (01:17:50)
Continuity mistake: While Quint leads the shark into the shallows, Brody asks, "Have you ever had a Great White do this?" and Hooper is beside the foremast holding one of the rungs, directly under the crow's nest. However, in the next shot, he stands at the edge of the bridge deck, beside the rigging. (01:47:25)
Continuity mistake: After Quint states that it's a 25-footer, he rushes below deck and when he comes up with the harpoon case, the gauges on the panel to his left are visible. When he answers the call from Amity Point light station, there is a new large black knob attached the corner of the panel, that was not there before. The paper mess at the top of the panel differs as well. (01:22:25)
Continuity mistake: In the scene where Hooper visits Brody's home, he brings two bottles of wine. Brody pours himself a large measure, and then gives his wife and Hooper some. If you look at the bottle a) it seems rather full for the amount he's just poured, and b) the level changes from shot to shot. Sometimes it's above the label, sometimes below.
Continuity mistake: At the end when Brody is up in the crow's nest of the Orca waiting for Bruce to get close enough for him to shoot the tank in Bruce's mouth, notice that the crow's nest is sinking much faster than Bruce is moving towards him. At these rates, the boat would have fully sunken before the shark got close enough.
Continuity mistake: On the dock, Charlie and Denherder wrap a link chain around the corner piling, which is yanked when the shark takes the roast bait. In the close-up the chain is pulled taught from the front and breaks free, but in the next wide shot the chain is slack and being pulled from behind the links around the piling. (00:26:25)
Continuity mistake: In the scene where Brody blows up the shark, off in the background there is land in some shots and then no land in others. At one point, there is land about half way across the horizon, then there is land across the whole horizon, and then no land, it varies shot to shot.
Continuity mistake: When the three men are in the cabin of the Orca at night, Quint is leaning forward against the table and is drinking something. In the next shot, as Hooper feels the cut on his forehead, Quint is turned towards the side leaning on the back of his seat, but in the next shot of Quint, he is leaning forward again in the same position as the first shot. (01:26:30)
Continuity mistake: While Brody starts to chum, Quint goes to the cabin to sit and work on the fishing reel, and the portable stove is visible to his right. Then when Quint speaks with Amity Point light station the pots, kettle, etc., on the stovetop are positioned differently and now there is an additional white pot. The hanging net has fewer things too. (01:20:50)
Continuity mistake: In a deleted scene, Quint walks into a music store to buy piano wire for his fishing reel. The woman behind the counter is giving a young customer a new clarinet reed and says, "It's a number three. It should be softer than the number two you had." Clarinet reed hardness is categorized with one being the softest and five being the hardest, so a three would be harder than a two.
Continuity mistake: When Quint stands beside the stove at his place, the stove is positioned a particular way in front of the wall. When he gives Hooper the rope, the stove is farther down against the wall and the wall behind the stove differs (note the panels), as do the roll shades on these windows. (01:07:00)
Continuity mistake: When Brody is in the flooded cabin as it tips, at the start of the shot where the shark makes its smashing entrance, we actually hear Brody's loud footsteps on wood, as we see his waist and legs run from aft to forward in the cabin; though in the previous shots Brody is more than waist level in the water, already standing towards the bow. (01:57:55)
Continuity mistake: The cleats are entirely different in many shots; they keeps changing from flat top, long, shiny silver with a wide base, to curved top, dull silver with a narrow base. When Brody unties the wrong line and when he wets the fishing reel it is the shiny flat top cleat on the transom. Yet, when he and Hooper tie off the lines the cleats are curved top. Also, the two metal plates and two metal hoods that are near the cleats repeatedly change from being very rusty, to not rusty at all. (01:17:40 - 01:22:00)