I've eaten a number of softshell turtles. You can cut them open with a knife, once you know where to cut between the top and bottom shells.
14" front to back was too small to keep, I'd catch them a LOT larger. They are harder to hold than a snapper because their tail is short - too short to be used as a handle. You have to grab one of their rear legs, and they can pull it back into the shell with a lot of force, making them hard to hold onto. Plus their necks seem to be longer than a snappers, so holding them out away from your body where they couldn't reach your leg was a challenge.
Biggest one I had hooked got away. The landing net was over 24" wide and it wouldn't fit into the net.
Grab their nose with a pair of pliers, pull their head out away from the shell and cut it off with a hatchet. Hang them by a hind foot to drain. Their legs still moved over an hour later when I'd skin them out.
Now I see where you can insert a needle and use compressed air to help loosen the skin from the meat.
