Continuity mistake: Near the end one of the balloon's ropes is shot, causing the girl to fall in the water. Yet, seconds later as they float off all 6 ropes are holding the basket up, uncut.
Continuity mistake: After the Smokers go for the Mariner's bag of dirt, there is a shot of the Mariner's boat going by. In this shot, the boom is over the starboard side, however, in the following shot, the boom is over the port side. (00:08:05)
Continuity mistake: When the Deacon begins his speech near the end of the movie, he is holding a bottle of liquor that is almost empty. Half way through the speech, the bottle is half full. Then when the girl is brought out, the bottle is now almost completely full.
Continuity mistake: As the Mariner readies to shoot the line off the Sky Boat, he has his knife in his mouth. After he falls in the water, it's suddenly back in its scabbard.
Continuity mistake: After the plane starts circling the boat, Helen prepares the harpoon gun. The barb on it is about four inches long, and is tilted about 45 degrees to the left (from the Helen's view). When the shot cuts to the circling plane, the barb is now straight up.
Continuity mistake: When nearing the trading post, the Mariner spots some globs of oil. When he goes to put his hand down to catch some, there isn't anything in the water, but his hand comes up oily.
Continuity mistake: When the Mariner escapes the Smokers for the first time, we get a wide shot of him at the helm. During the first shot, the boom is nearly straight over the boat and the outhaul is tensioned. In the shot afterwards, the boom is much further outward, and the outhaul now has lots of slack.
Continuity mistake: When Helen first pulls the Mariner up in the cage, his face is covered by the recycling goo, with lumps all over his face. After the cut to Helen for her line, his face is wet, but clean.
Continuity mistake: As the first skiers are being towed by the Sky Boat, two head for the left ramp, two go to the right. When the angle reverses to see them going up, all four appear to be going up the same ramp.
Revealing mistake: After the Mariner has Enola, the Deacon and his goons collide. In slow motion, the three of them are exploding a split second before the collision, and they're several feet from each other.
Revealing mistake: When escaping the Smokers for the third time, the Mariner picks up Enola and swings to the other side of the boat with a rope. But you can see a second rope going down behind Costner's back. At the ''handle'', it's tied up with the one Costner is actually holding on to. (01:18:25)
Answer: Sealed stuff floats. They gather stuff just like the mariner.