There is a double figure here. The
flood symbolizes baptism, and
baptism symbolizes salvation.
The text of
1 Pe 3:20-21 reads: ". . .
the longsuffering of God waited in the days of Noah, an ark being prepared in which a few, this is eight souls, were quite saved through water. Which figure (baptism is a figure/symbol of Christ's death, burial and resurrection which saves) also now saves us, that is baptism, not a putting away of the filth of the flesh, but an answer of a good conscience toward God through the resurrection of Jesus Christ."
The flood symbolized baptism which
baptism symbolizes Christ's death (judgment), burial and resurrection which saves.
The
flood is a
symbol of
baptism in that in both instances the water that spoke of
judgment (in the flood, the death of the wicked; in baptism the death of Christ and the believer,
Ro 6:2-4) is the water that
saves.
Baptism is a
symbol of
salvation in that it
depicts Christ's death, burial and resurrection and our identification with him in these experiences.
"Also now saves us," in the context of the
rest of the NT, means saved by what baptism
symbolizes--Christ's death and resurrection (
Ro 6:2-4).
This using of the
symbol to refer to the
reality is, as I understand it, what the Catholic church calls "sacramental union."
"answer of a good conscience toward God" is a commitment on the part of the believer in all good conscience to make sure that what baptism symbolizes in
Ro 6:2-4 will become a reality in his life; i.e., that
as Christ died for sin, so the believer will die to sin.