An aquatic shredder includes a watercraft and a pair of large, high speed propellers mounted at both the bow and stern ends of the watercraft. In some embodiments, the device gamut may be represented in a device independent color space, which may be a perceptually uniform color space. The shape of the curve representing this time dependence is evaluated on the basis of a pre-specified comparison criteria, and the power input to the ultrasound transducer andor a bond weight exerted on the wire isare controlled in dependence on the result of this evaluation.