Dr. Arzt, the school teacher, blew himself up while handling some of the volatile dynamite
The ship originates from Portsmouth
Theories
The Black Rock was wrecked on the island because of the mysterious ability that the island has that enables it to attract boats and aircraft. Some have called this ability a strong magnetic field, but the Black Rock does not appear to be a metal ship. The island may have the power to attract other things as well, ie. Desmond's race-around-the-world sailboat.
Greek myth states that Prometheus was tied to a Black Rock, possibly a mountain, as a punishment from Zeus. Prometheus features heavily in the story of Pandora's Box, which the hatch is speculated to be (Locke says, he thinks hope is inside, just as with the Pandora Box myth)
The Black Rock could be an old slave ship. When Jack goes inside to find the dynamite we are shown that some of the shackles are unlocked. It is possible that some of the slaves escaped and proceeded to inhabit the island, maybe their descendents still do?