What exactly did you use on the Laci Peterson search?
GR: We used a customized Marine Sonic Technology sidescan sonar. We have a custom-made stainless steel tow body for the 600 kHz transducer. The towfish is six feet long and weighs about 130 pounds. The extra length makes it more stable and, consequently, the images are better. The heavier weight allows us to work in deeper water with less cable.This setup requires the use of a powered hoist to deploy the system. Our hoist has a variable speed electric motor with a remote control and is also equipped with a slip clutch to prevent cable breakage if the towfish snags on something underwater. We also used an aluminum tow body for the shallow water in San Francisco Bay. The lighter weight of the aluminum gave us greater layback and tended to somewhat de-couple the towfish from boat pitch and heave due to surface wave action. UW: Do you use different units for different searches, why or why not? GR: We use the aluminum tow body when we have to air freight the equipment and use a boat of oppo