echo sounder puzzle

[Guest]

Why is it that when i turn on my Furuno 1650-f echosounder i don't get any depth reading & no bottom picture when i ecxeed 200meters at slow speed & even when drifting, yet at about 150meters at 20 knots i get a crystal clear reading, does altering the transducer angle have any effect on this? mine is a few degrees off without a fairing block.

 

[charles_reed]

It's outside the depth at which your transducer will work - mine packs in at about 160m and gives errant readings of the top, warm stratum.
It's quite unnerving having the shallow alarm go off in 1100m of water.

 

[Strathglass]

Just think what it feels like when the shallow alarm starts off in the middle of Loch Ness.