The Tempest : What was Prospero's original plan?

The Tempest may end happily enough with everything working itself out, but it doesn't start that way. Fate has placed Prospero's enemies within his reach, and he promptly crashes their ship on his island. Somewhere along the line he decides that the best move is just to reveal himself and get a ride back to the mainland.

But was that his original plan? He's obviously got some pent up anger over having been exiled here in the first place. He could easily have sent the ship and all its passengers straight to the bottom of the sea, too.

Was Miranda falling for Ferdinand part of the plan? Was his daughter his motivation for getting off the island in the first place? Or did he change his whole plan around to accomodate her?