In the scene where Truman (Jim Carrey) is in the sailboat, almost to the very edge it shows a shot of him sitting on the right side of the boat wearing a green shirt and black pants. A second later it comes back to him and he is on the left side of the boat wearing a blue shirt and khaki pants! Can you beleive it?!
The clothes are a valid slip-up, however being on the different side of the boat is not. Occasionally while sailing the class of sailboat that Truman was in, you have to change sides (especially in rough weather) to balance the boat and keep it stable, the boom also swings around due to the wind direction so you would have to change sides :)