Early in the film Bud throws his wedding ring down the latrine and then retrieves it with his right hand so it is covered with the blue disinfectant. In a (much) later scene, Bud has a blue right hand, despite not having had one in the intervening period.
The dead sailor harbouring a live crab, spooking Jammer out of his wits in the sunk submarine, is director James Cameron's younger brother Mike. The scene had to be shot several times to get it right, forcing Mike to hold the live crabs in his mouth, until the cry for "action", before releasing them. At one point he had to crush one with his teeth, as it gave him quite a bit of grief. Brotherly love immortalized.