Notice how Peter says baptism does "also" save you. Of course he is going on the previous verse which says the water saved Noah and his family. Many people have the false notion that it was the ark that saved Nola but in fact the water saved Nola through its properties of causing the ark to float upon it. Many people have used gallons of ink to try and disprove the water saves. God chose water as the media by which we can contact the blood of Christ through burial Romans chapter six versus 3 to 4. The main opponents of water baptism saves of those connected to Calvinism or what came from Augustine and they are followers of faith only salvation.