Hawkeye DF1120S micro display depth finder

[makmend]

I am having problem finding a suitable location for the transducer in my 2007 speedster 150.
So far I found that the best location is just ahead of the pump beside the shaft port side. It works fine if the boat is stationary, however once the speed is slightly above idle the depth reading is just "-----". Once the engine is put back to neutral sometimes the display returns back, sometimes just the "----".
I tried the water bag, filling the bilge with water, and petroleum jelly and can not get a good reading. I tried several location so far no luck.
Thanks for any feedback.

 

[kustomkarl]

It's just trial and error. If the bottom is real silty it will also show "-----" for the bottom depth. It needs to have a sold or hard bottom to receive the pulse from the transducer.

Karl