Continuity mistake: When Brody waits to board the ferry he says, "Charlie, take me over to those kids, will ya," and there's a painted board with 'Amity' attached to the ferry base. However, when they reach the other ferry landing the board with 'Amity' is gone, in sloshing water (even more visible in a deleted scene). It's the same side of the ferry, note the ferry Captain is stationed at the permanent helm at only one side. The short haul Chappy Ferry On Time scow was the stand-in for the fictitious Amity ferry. (00:11:40)
Continuity mistake: During the scene where Quint, Hooper and Chief Brody are in the cabin at night and Quint tells the story of the USS Indianapolis, he puts his cap on the table, seconds later it disappears then later reappears. The fork on the plate also turns completely around, without anyone ever touching it. (01:25:50)
Continuity mistake: After Hooper pulls the tooth from the hull of the boat, in the shot just as Ben first pops out, the knife Hooper holds has a protective sheath on the blade, yet in the previous and following shots the pointy serrated blade is not covered. (00:49:30)
Continuity mistake: In the close-up of the stern cleat as the shark pulls on the line, there are two large metal 'L' shape brackets screwed onto the corner of the wood of transom. Amazingly, these large brackets are not screwed into the wood in the close-up, as Brody winds the line round the cleat just a moment earlier. The metal brackets repeatedly appear and disappear. (01:42:30)
Continuity mistake: There is a scene where Chief Brody and his wife are talking about their son's birthday present. She says that he probably won't go in the water after what happened yesterday (the attack on the Kintner boy). The next day is when the shark is caught and Hooper makes a comment about the shark's digestive system being very slow and anything he's eaten within the last 24 hours would probably still be in there. From the earlier scene it would make it 48 hours since the Kintner boy was killed. (00:35:20)
Continuity mistake: When Mayor Vaughn, Hendricks and the others join Brody on the ferry, as they reach the other side of the harbor the coroner's front leans on the car, as he faces the Mayor and Brody. However, in the next shot the coroner's back now leans on the car, as he faces the opposite way. (00:13:25)
Continuity mistake: When Chief Brody asks, "How many guys you gonna put on that boat?" he stands between two adjacent pilings. Hooper then stands beside the same two pilings in the following wide shots. However, in the close-up when Hooper asks about a good restaurant on the island, he is at the center of the shot standing beside only one lone piling. Richard Dreyfus' beard is also fuller in the close-up, than in the wide shots. (00:28:50)
Continuity mistake: As the shark pulls on the lines tied to the stern cleats, the boat tips to the side and in the wideshot the emblem on one of the air tanks faces the side. Yet, in the next close-up as they hit the ladder, both face front. (01:43:05)
Continuity mistake: Just after Hooper remarks, "Fast fish," as they chase the shark, there is a close-up of Brody leaning over the starboard side of the boat, beside the boat's wake. However, in the previous and following wideshots Brody is at the port side of the boat, as it speeds after the shark. Neither are flipped shots. (01:40:35)
Continuity mistake: After buying the sign supplies, Brody drives away and as the Mayor calls out to Brody, Hendricks walks over. In the first shot certain people are walking about; however, in the next shot as Hendricks and the Mayor speak, a boy suddenly appears standing in the crosswalk, the positions of signs, etc., differ, and of course the shadows cast are entirely different. (00:11:15)
Continuity mistake: Quint remarks, "Back home we got a taxidermy man. He gonna have a heart attack when he see what I brung him." In the shot of Orca's stern, just prior to this comment, the two attached yellow barrels are very worn, with many black marks all over. Yet, in the shot right after, both yellow barrels are almost entirely yellow - quick paint job. Throughout the Orca scenes the marks on all the barrels change many times in consecutive shots. (01:43:20)
Continuity mistake: During numerous close-ups on the bridge deck, such as when Brody is behind the wheel, as Hooper shouts, "Our injectors got scored from the salt water in the fuel," the three large gauges over the steering column are seen. The center gauge has a wide shiny chrome trim, and a partial black face with a silver center. However, in the extreme close-up of the gauge panel, it is an entirely different style RPM gauge, and it now has a blackish rusty trim, and a solid black face. (01:41:00)
Continuity mistake: When the shark is boarding the boat, Quint and Brody are on their backs in the cabin beside the table. It is clearly visible that they are lying on the very solid floor with the hatches in perfect condition, despite the visibly massive damage to the floor and hatch when the engine room exploded. (01:57:00)
Continuity mistake: Just as the first cleat flies off the stern of Orca, the shape of the small metal hood differs and the entire wood rail at the top of the transom in this close-up differs from the rail in all other shots. The long wood rail has another small piece of wood attached at the end, forming an 'L' shape with a 90° angle, whereas in all other shots the rail is one long solitary piece. (01:44:55)
Continuity mistake: When Chrissie goes swimming at the start of the film, we see the moon in the distance. However, when we see Chrissie from the shark's point of view under the water, the moon is directly above Chrissie.
Continuity mistake: When Brody sits on the beach watching the crowd in the water before Alex is killed by the shark, he wears a watch on his wrist which disappears a few shots later when he believes he saw something. (00:14:48)
Continuity mistake: When Hooper asks Quint about being on the Indianapolis, both of his shirt buttons are unfastened. When Quint answers & starts telling the Indianapolis story, Hooper's bottom button is fastened. (01:29:20)
Continuity mistake: In the famously later on added scene Ben Gardner's suddenly emerging head scares the hell out of Hooper the diver (as well as any viewer). What diminishes the effect is that the second close-up of the head looks nothing like the first, much creepier one.
Continuity mistake: When Brody fires the last shot at the air tank, in the next close-up of the shark, the tank lies parallel to its body deep within its mouth, with only the base of the tank visible between its teeth. However, in the next wide shot, the tank lies perpendicularly in its mouth, with the pressure knobs at its right. (02:00:10)
Continuity mistake: During the shark's attack on Orca, the tall, large steam pipe clamped to the wall, beside the bridge deck ladder, actually differs from the steam pipe seen in previous shots. (01:49:55)
Chosen answer: As mentioned in the movie, the posion was in the needle and the shark's hide was too tough for the needle to penetrate. Hooper had to go in the water so that he could get the needle into the shark's mouth, where the flesh was less tough.
Kevin Howard