The allusion is that the flood of Noah prefigured Baptism. What is not an allusion is the simple statement: "… baptism, which saves you now." It is only because you are coming to Scripture with the preconceived notion that Baptism is not necessary for salvation that you must find ways to negate these passages. Thus this is just one example of Protestants putting the teaching of the Reformers above the plain words of the Bible.
If Peter is saying baptism is required for salvation, how can you possibly harmonize the Romans 10 passage (and an absolutely huge array of other passages) that do not mention baptism at all?
Quite simply, if you have faith then you believe all that Jesus taught and commanded, including the necessity of Baptism.