You might not get eaten, but you can still get bit and come back minus a hand or foot. I've skin dived in around here in Indiana and encountered alligator snapping turtles with heads the size of a small canteloupe. NOTE: They like to hang out in the opened trunks of sunken cars for some reason. Trust me I got a nice close look at one....started wearing chain mail gloves after that (that way the hand surgeons at the local hospital might still have something to work with).
I have seen, out of the water after being caught and dragged ashore, a snapping turtle that was bigger around than a manhole cover (approximately 2.5 feet across the shell and in excess of 50 lbs.). The guy shot it in the head with a .30 caliber rifle and it didn't die. They are tough SOB's. I'd take a barracuda in clear water any day.