Jack Sparrow: what has become of my beloved Pearl?
Barbosa: I lost the Pearl as I lost my leg.
Jack Sparrow: - Lost the Pearl?
Barbosa: - Aye.
Barbosa: I defended her mightily enough, but she be sunk nonetheless.
Jack Sparrow: If that ship be sunk properly, you should be sunk with it.
I don't understand why be is used here twice. Is it archaic? Why use this form? And what does properly mean here?