Night Moves

Four men in the movie stunt business join together to smuggle precious Mexican antiquities to the States. All are pilots except for mechanic Quentin (James Woods). One of the pilots, Tom Iverson (John Crawford), also has a charter business in the Florida Keys, used as a staging point for the smuggled goods. Iverson's girlfriend Paula (Jennifer Warren) is also in on the scheme. All of this occurs before the movie opens; all that follows happens during the film.Los Angeles private eye and former NFL player Harry Moseby (Gene Hackman) arrives at the Keys searching for Iverson's runaway, nymphet stepdaughter Delly (Melanie Griffith). Moseby was hired by Arlene Iverson, Tom's selfish ex-wife and a former actress. Arlene's only means of support is Delly, Arlene's daughter by her first husband.After Moseby takes the case, he discovers that his wife is cheating on him, but instead of talking to his wife Ellen (Susan Clark), he accosts the man she has been seeing, Marty Heller (Harris Yulin). Marty despises Harry for acting like a private eye instead of taking care of his own marital problems. Although they eventually reconcile, Ellen also despises Harry for treating her like a case subject instead of his wife.As Moseby follows the clues to Delly, he makes fast friends with stunt director Joey Ziegler (Ed Binns) who is keen to help Moseby find Delly. Moseby discovers that Quentin and stunt flier Marv Ellman (another smuggler) were both once involved with, and fought over, Delly, although Moseby has no suspicion of the other motives and machinations occurring under his nose. Moseby eventually finds Delly with Iverson and Paula in the Keys, and they allow Moseby to stay for a while as he tries to convince Delly to come back to L.A. with him.During a boating trip one night with Delly and Paula, they find Ellman's downed plane. Paula deceives Moseby about a marker she places at the crash, saying it is for the Coast Guard. It is really for Iverson who will come to the site later and retrieve the stolen goods from Ellman's plane. During this time, Paula seduces Harry to keep him occupied. Delly eventually comes back to L.A. with Moseby, finding Quentin waiting for her at Arlene's home.It is the last time Moseby sees Delly alive, with everyone at the house yelling at one another other while Harry drives away, not reflecting on the turmoil he has once again introduced into Delly's life.Arlene gets Delly some movie extra work but she dies in a car crash during a stunt in which Ziegler was driving, who lived but was badly injured. Moseby views film footage of Quentin under the car before the stunt and begins to suspect Quentin murdered Delly. Moseby confronts Quentin and accuses him of killing Delly because she discovered he killed Ellman out of jealousy. They fight but Quentin escapes. Moseby then tells Ziegler he thinks Quentin and Iverson are in on something but he doesn't know what. Moseby goes back to the Keys to find out.Moseby arrives at Iverson's charter business to find Quentin dead. Moseby then confronts Iverson who confesses to killing Quentin. Quentin thought Iverson killed Ellman to get a larger share of the smuggling proceeds, and Moseby had scared Quentin into thinking he was going to go down for Ellman's murder instead. Moseby struggles with Iverson and knocks him out, then is determined to finish things by having Paula help him locate the stolen artifacts.They find the marker previously left, and while Paula is underwater, a seaplane strafes the boat and Harry is injured. The plane lands and sees Paula surface along with a large stone sculpture. The plane runs her down but then collides with the sculpture, kicking out its pontoons. The plane then flies into the boat and begins to sink. Harry tries to get a glimpse of the pilot from the diving window built into the boat's keel: it is Ziegler, the last person he ever suspected.The movie ends with Harry unsuccessfully trying to steer the boat to shore - he succeeds only in going in circles.

Question: What is the boat doing at the end of the movie?
Answer: Going in circles