Piver conversion daggers or keel ?

[Cavalier MK2]

Like a Wharram they have more wetted surface do to the V hull shape but the amount of boat in the water is a matter of displacement, not the number of hulls so there isn't really a drag penalty there. Wave interferance between close hulls is a more likely candidate for drag. If not over loaded though, a Piver can be fast off the wind, nothing like surprising the unwary with a speeding box!