Find a water depth sensor ?

I'm looking for a water depth sensor (sonar transducer not pressure sensor).

  • Operating range 1 meter to 30 meter

  • Output signal : analog 1- 5 vdc proportionnal or Pulse width modulation (for arduino)

  • Power supply : < = 12 Vdc

  • Refresh time < 1 sec

  • Environnement : Salted water, installed on a moving buoy (movement causing by wave on a open water plan)

Can anyone help to find this kind of sensor (and controler) ?

Thank for your help

Alain

In another thread someone recommended this one:

http://www.ebay.com/itm/Marine-Digital-Water-Depth-Sounder-Deep-Shallow-Alarm-/220698970051?

It puts out the depth over a serial connection (4800 Baud).

Thank for the hint.

Did you know which thread ?