I just install a D10D depth finder, My booat is on a work rack. Should I be receiving any data, depth form the unit when on a work rack?
If the transducer is not in contact with water, you will not see any depth data.
The unit works by sending out faint clicks from the transducer (you should be able to hold your ear to it and hear the clicks). The sound waves bounce from the transducer to the bottom of the lake/sea/river and return to the transducer. The delay in their return is times to determine the depth.
But the sound waves cannot travel efficiently through air. So even if the transducer is slightly above the surface of the water, it cannot produce a depth reading.