My wife and I ate at the Shrimp Dock at 11124 Kingston Pike in Knoxville on our way to Kentucky. Brawny is correct that they aren't a restaurant. The only thing on their "menu" are po-boys. The po-boys are GREAT. Cole slaw is excellent also. If you are looking for a lunch break in Knoxville, I recommend this place.
I haven't eaten there, in the strictest sense of sitting there and having a meal.
I do buy my seafood from them. I also buy their ready-made, frozen meals and everyone of them that I've bought has been as good as I would make. They are also my source for andouille sausage and they even have dried cod (much beloved by certain folks in New England.)