depth finder![click to hear](/images/speaker.jpg)
Device that uses a sonic pulse to measure the depth of water below the boat.
alarm threshold setting ![click to hear](/images/speaker.jpg)
Knob for setting the maximum depth considered to be dangerous.
gain control ![click to hear](/images/speaker.jpg)
Knob for adjusting the amplification of the signal.
on-off switch ![click to hear](/images/speaker.jpg)
Button for activating the sounder and for selecting the scale.
sound alarm ![click to hear](/images/speaker.jpg)
Audible signal activated when the alarm threshold is reached.
housing ![click to hear](/images/speaker.jpg)
dial-type display ![click to hear](/images/speaker.jpg)
Display surface where an illuminated dot appears at the point on the scale that corresponds to the depth.
depth scale ![click to hear](/images/speaker.jpg)
Line graduated in feet or meters for reading the distance to the bottom.
echo sounder probe ![click to hear](/images/speaker.jpg)
Part of the sounder that is submerged to send the ultrasound to the bottom; it receives the echo and converts it into sound.
transmission cable ![click to hear](/images/speaker.jpg)
Electric wire that relays the electric signals between the housing and the echo sounder probe.
plug ![click to hear](/images/speaker.jpg)
Metal prong that plugs into the housing.
transducer ![click to hear](/images/speaker.jpg)
Part of the echo sounder probe that emits the ultrasound and receives its echoes.