Christ is the ark in which we find our deliverance, but it is through the water that we bury our old sinful life behind. Just as Noah and his family escaped their corrupt world through water, so we too make our exit from this world system through baptism. Hence, when we are baptized in water, we publicly proclaim our deliverance from the world system. We outwardly testify that we have left our old world behind. Peter goes on to say that baptism is a pledge a testimony of a good conscience before God.
Biblical baptism is accomplished by full immersion.
As you go under the water you are taking the world that you used to love under God's judgment. The kingdom of the enemy is being buried with you and you are coming up into Christ the real ark of safety. The other kingdom that you used to serve lies in the water finished and buried. What is more, you are testifying to the fact that you are passing into God's kingdom where He is your new authority now. Through baptism, you testify to men, angels, demons, and to God that you have died to the old creation and that you are part of the new creation, where Jesus Christ is your Master.