What your really need to do is train the damn dog. It's not a person, it's a dog. If the dog is eating stuff out of your tank bag it is probably eating stuff off the kitchen table too, right? Is this acceptable behavior? The kids will enjoy the dog a lot more if you train it properly too.
The first thing you need to do is commit to about 2 hours a day to training. If you can't do that, then you really shouldn't have a dog in the first place. Then call some local breeders and get the names of some recommended professional dog trainers. Have the trainer work with you, your wife and your kids so they all know how to control the dog.
It may cost you a few hundred dollars, but that is probably not much more than the value of the stuff the dog has destroyed so far.
I went through this with a Rottweiler a few years ago. It tried to eat every other dog that came within 20 yards of it. After we got done with the training, it never even looked at another dog. It also never jumped on anyone or any thing, never barked at anyone and would never leave the yard if we didn't put a leash on him.