Depth Sounder V Fishfinder

Seajet

Seajet

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Advice please; one of my depthsounders is U/S, and I'm thinking of replacing it with a simple fishfinder to get that bit more information.

However I see even the modest fishfinders mention 100watts transmit power, which is a lot for my boats' electrics to handle overnight - this would also be used for the shallow & deep alarms as 'anchor watch'.

Can someone please confirm if these things do require a lot more power than conventional depthsounders ?
 
Seajet said:
Advice please; one of my depthsounders is U/S, and I'm thinking of replacing it with a simple fishfinder to get that bit more information.

However I see even the modest fishfinders mention 100watts transmit power, which is a lot for my boats' electrics to handle overnight - this would also be used for the shallow & deep alarms as 'anchor watch'.

Can someone please confirm if these things do require a lot more power than conventional depthsounders ?
Click to expand...

Transmit power isn't the same as consumption.

Plucking a make and model from the air at random : http://store.humminbird.com/products/307114/345c

Transmit power is 300W, power draw is 380ma
 
Paul,

thanks; electrics never were my strong point ! However I see the NASA Clipper depth quotes a consumption of 20ma, + 25 for the backlight; so the fishfinder is a fair bit more, which I can understand as it's doing more.

Will have to think about this one...
 
Hi
I think the bottom profile shown on a fishfinder display shows a lot of extra and useful information over and above a plain depth sounder and the power consumption differences are still small parts of one amp. Many fishfinders also show useful info such as Battery Voltage and Water Temperature.
 
catalac08,

I agree, that's why I fancied a FF, but as I rely on a 30 watt solar panel & trickle charge from an occasional outboard, I have to be careful with power...

Thanks,

Andy
 
I have just fitted a fishfinder to my little motor boat.
I got it with another boat a bit ago and haven't used it up to now. It's an Eagle Finder.

The information is amazing. If there really are fish where it says there are I may start a trawling operation on Windermere........

Luckily I can take the (car) battery home a short walk (with wheel barrow) and recharge at will.
 
Be aware that what your seeing on the screen you've already passed! Also, just because theres a little fish icon on the screen doesn't actually mean its a fish. Mine used to pick up all sorts of rubbish and decide that it was fish it was seeing.

Good bits of kit, even the budget stuff, but needs a bit of understanding to use it effectivly.
 
PaulGooch said:
Transmit power isn't the same as consumption.

Plucking a make and model from the air at random : http://store.humminbird.com/products/307114/345c

Transmit power is 300W, power draw is 380ma
Click to expand...

So it consumes 0.38 Amps at 12V so it consumes 4.56 Watts.

But it has a transmit power of 300W :eek:

they must use the same bizarre method of power measurement, as cheap hi fi's and car radios, that proclaim ridiculous power outputs.
 
BarryH said:
Be aware that what your seeing on the screen you've already passed! Also, just because theres a little fish icon on the screen doesn't actually mean its a fish.
Click to expand...
Depth sounders aren't particularly forward-looking are they?

I've worked out what cavitation and the sounder head leaving the water looks like.


This was today. Not many fishys though.

​
 
On my first "Raggie" it had 2 depth sounders, one angled at 45 degrees forward, this gave a good indication of when the ground started to shallow,but u/s for anything else.
 
ProDave said:
So it consumes 0.38 Amps at 12V so it consumes 4.56 Watts.

But it has a transmit power of 300W :eek:

they must use the same bizarre method of power measurement, as cheap hi fi's and car radios, that proclaim ridiculous power outputs.
Click to expand...

But it's pulsed power - the average power is much lower. Like radars that transmit 2 megawatts (typically)! But only for very short periods of time :)
 
ProDave said:
So it consumes 0.38 Amps at 12V so it consumes 4.56 Watts.

But it has a transmit power of 300W :eek:

they must use the same bizarre method of power measurement, as cheap hi fi's and car radios, that proclaim ridiculous power outputs.
Click to expand...

It's just maths

the 12v power consumption is an average

the transmit power is peak level

The transmit power is given as a set power at a set frequency
400W pulsed for 1/100 sec gives an average power consumption of 4W.


Cheap hifi's use peak transient power to make them self sound more powerfull :cool:

Decent Hifi's use RMS (the equivalent DC power )




Doh !! Hoolie beat me to it :-)
 
Hoolie said:
But it's pulsed power - the average power is much lower. Like radars that transmit 2 megawatts (typically)! But only for very short periods of time :)
Click to expand...

Thanks to both of you.

That explains it nicely. so they are not cheating. Unlike cheap hi fi manufacturers who will tell you any rubbish if they think it sells their stuff.
 
Well it is just mathematics really. The set sents a current to the transducer [piezo electric] which vibrates sending a "sound" down a cone. When it hits something it returns to the transducer and the signal is then processed mathematically. The lcd screen in small machines interprets this signal into a picture[history] of what happened recently in a pleasing form for the punters. Real time is on the very edge of the screen or on an A scope on up market machines.
Interesting how flasher sounders are the big thing in ice fishing in the states. Flasher sounders are just A scopes in a circle. Check out Amazon.

Some small sounders can be powered by batteries in the back as well as 12v ships supply.
 
Seafarer 700 flasher is only a 100 watt machine but its maximum consumption is 120mA on all ranges, 105mA shallow and 65mA on deep. A 1kw sounder with a crt uses about 10 amps max. Small LCD 300watt sounders use about 350mA with the light off and 500mA with the light on.
 
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