RAYMARINE RAY-E70059 / i50 Depth Display Only

So, as you can see we are still on land and  recently i replaced the speed transducer and the   death transducer. Naturally I wanted to find out  if they work before I put the boat into the water   which is quite easy with the speed and temperature  transducer. Here you just move it like this   and you get a reading. The detph transducer  is a little bit more problematic because it   doesn't work when it is on land. The transducer is  a P319 by airmar and the instrument I'm using is a   Raymarine i50. If you try to test the instrument  on land you just get dashes in the display.   If you disconnect the transducer it also shows you  dashes. So effectively you have no way of finding   out if your newly installed transducer works.  The manual was of no help either but i found   this little trick which i wanted to show you. I  built this nice little high-tech device here made   out of some