We arrived on site just north of the Chesapeake Bay Bridge near where the main channel gets shallower to the north. We deployed the Scanfish at 0800 and began towing to the south. The Scanfish is a big yellow wing-like device that undulates up and down through the water-column measuring salinity, temperature, oxygen, fluorescence and turbidity. We towed it to the mouth of the Choptank R. when Mary Doherty noticed that the air conditioner in the isotope van stopped working. It got really hot in there. So we continued towing to the mouth of the Patuxant R. and arranged for HVAC repairmen to meet us at the dock at Chesapeake Biological Laboratory in Solomons, MD. We pulled the scanfish out of the water and docked at CBL next to the R/V Rachel Carson. After a couple hours, a lot of head scratching, and a little acetylene torch action the AC was fixed and we headed back to the deep channel of the Chesapeake Bay to continue our scan. Unfortunately the Scanfish stopped working. Wynn Tucker and Mary Moore repaired it and we were off again. We finally finished our Scanfish survey off the mouth of the Rappohannock R. at 0430.