VDO depth sounder....how does it work?

[dpb]

Found these items fitted to my boat when I bought it.
Originally thought one part was something to do with the anchor controls, mainly due to the anchor picture on it, but now realise both parts are a depth gauge......I think!
Anyway can't work out if or how it works, have scoured the internet but no joy.
Any ideas?

 

[epervier]

The one on the left is the depth head and is in both feet and metres,showed as shadow bars in the port and stb windows, the window at the bottom shows numbers, ie, 2.4 mtr or in feet, it was independently switched on the helm switch panel, the instrument on the right is for anchor watch/alarm, as it was fitted to my Portofino,

 

[dpb]

Thanks for that, the boat in question is a Portofino also.
I've got the switch on the dash and the gauge illuminates when it is switched on but nothing else. The boat is out of the water but I thought it would at least show zero or some random digit when switched on as all my other sounders have done.

Any idea how the anchor watch part works?
They are certainly connected behind the panel.

 

[epervier]

The guage will only work when it's in the wet stuff, it needs to send a signal from the transducer and bounce back from the seabed and the water is it's medium, from memory the transducer is inbetween the engines just aft of the fresh water tank, as to the anchor alarm/watch, I'm afraid I've forgotten how to set it, as in the four and half years of owning her I used it once and then had to refer to the idiots guide, which has gone with the boat to the new owner.