On the inspector's boat Frank's wrists are handcuffed together with a railing between his arms to secure him in place. There is a very short chain between the cuffs, 4 to 5 inches at most. When he's pulled free by a rope from Elise's boat he starts 'climbing' the rope hand over hand. In one shot his hands are over a foot apart, he's obviously not wearing the handcuffs. When he gets onto Elise's boat his hands are cuffed once again, she shows him how to pick the locks to get the cuffs off.