# Seafarer 3 Depth Sounder



## oft (Apr 25, 2006)

Does anyone know the frequency of the through hull transducer that would have come with a 1976/77 Seafarer 3? I'm hoping to replace this depth sounder with a fish finder (e.g., Furuno LS 4100 {50/200kHz}) without having to replace the transducer (located on the stbd. side of the hull about a foot to the side, and towards the front, of the iron keel). The Seafarer works well enough but seems a little hard to read. Any comments on this idea? I've checked around but cannot seem to find this transducer frequency anywhere. Thank you.


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## sailingdog (Mar 19, 2006)

You'll probably need to replace the transducer, as the typical depth sounder will not have the right frequencies for a fish finder. Fish finders and depth sounders are related, but fish finders require much higher resolution than do depth finders, and generally use several frequencies to give better resolution at various depths. I doubt that the depth sounder that you have uses a transducer that the fishfinder will work with.

Are the depthsounder and fishfinder even the same brand?


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## sailandoar (Mar 20, 2006)

(1) Seems unlikely to me (wild guess on my part) that a 1970's era depth finder would be multi frequency. 
(2) Get an O-scope and crack the case on the old sounder and hook to the leads that feed the transducer and look at freq/period of the wave form.
(3) What makes you think the old depth sounder is multi-freq and more than that is a 50/200kHz?
(4) Call tech support of the new depth sounder company and ask them what they think/know.


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## oft (Apr 25, 2006)

Sorry for the lack of clarity in my post. The Furuno LS 4100 that I hope to replace the old unit with is 50/200kHz. One of the experienced techs that I talked to thinks the old Seafarer 3 transducer is 200kHz, but is not sure. The salesman says that if it is indeed 200kHz then I should be able to use the Furuno.


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## sailandoar (Mar 20, 2006)

200kHz is a common Freq however you should avoid taking the technical advise of sales folks unless you have some specific reason to think they they are qualified to speak on such matters. Ask the tech if he/she thinks the dual freq Furuno will work on the single freq old transducer.

Does not sound like a good thing to me. Hard to imagine that the dual freq Furuno will be happy with a single freq transducer, or that the plug and the number of conductors will even matchup. Further, the power output of the Furuno may exceed the design power of the 30 year old transducer. Think you need to bite the bullet and swap transducers. I have to do that on my next haul out. 
Oh Well!

Will warrenty cover the Furuno if the control head gets smoked by running on the old transducer?

Before the discussion goes much further you need to check the pinout / #conductors on the old vs the new unit, that may decide the question and end the discussion.

Good Luck


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## sailingdog (Mar 19, 2006)

I've found that many salespeople will blow smoke at you, just to get you to buy... but most are not qualified to give you any technical advice.


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## Valiente (Jun 16, 2006)

I believe it's a 150 Khz transducer and they are still available in Europe. Google "Seafarer 3 Echo Sounder".


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## TSOJOURNER (Dec 16, 1999)

*Seafarer 3 Echo sounder*

Hello,
I have the manual for the Seafarer 3 Echo sounder. It is for sure 150HZ. I see this post was from quite a while ago, but I would like to find the instrument for the Seafarer 3 echo sounder without the transducer. Did you end up switching out your fathometer, and is the instrument still around?

Thanks!


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## Valiente (Jun 16, 2006)

I have one PLUS a fishfinder. Frankly, I've never bothered to locate the Seafarer's transducer...it must be directly under the nav station in the old boat.

So I've kept both operational. I find with certain bottoms, the fishfinder isn't quite happy to give a consistent depth, whereas the Seafarer will give, when the gain knob is tweaked, as accurate a measurement in chains or fathoms or drams of sheepfat as it is capable of giving. I enjoy its cathode-lit endurance...it's easily the most ancient working bit of electrical gear aboard.


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## julianc (Apr 15, 2008)

I have one, would like to add a repeater output - does the manual have a circuit diagram?

Anyone know the impedance of the transducer in case I want to re-use with a homebrew circuit?

Julian


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## cormoran (May 26, 2010)

*Seafarer Mark 3*



lilledanserboatandbreakfa said:


> Hello,
> I have the manual for the Seafarer 3 Echo sounder. It is for sure 150HZ. I see this post was from quite a while ago, but I would like to find the instrument for the Seafarer 3 echo sounder without the transducer. Did you end up switching out your fathometer, and is the instrument still around?
> 
> Thanks!


Hello ,I have 2 instruments and a new transducer.Since there is a fault with both I am looking for a wiring diagram.Can anybody help ?

Thanks


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## julianc (Apr 15, 2008)

I have a diagram but it doesn't have component values and probably wont scan. My Seafarer3 is currently not giving any readings. I'm hoping the transducer is just clogged with Essex mud. I'll look out the diagram and see what can be done with it.


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## cormoran (May 26, 2010)

*seafarer 3 depth sounder*

Thanks very much julianc
Does the manual tell you how to adjust the depth ? I am about to give up with the Seafarer.But being a steel boat means cutting a new hole in the hull since all transducers have a bigger diameter .But awould try once more if I had the manual and the wiring diagram.My son lives in Canada ,maybe you could copy it and send it by mail.Please let me know if that is possible.

Regards Cormoran


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## julianc (Apr 15, 2008)

I can have a go, but its about a 5th copy already - I tried re-drawing it but didn't get very far.

I don't have a manual sorry - just the schematic. I don't think there is any user way to adjust for transducer to keel, there might be a variable resistor deep inside but that would be quite difficult to calibrate.

The big benefit of these old machines is that they are analogue. Digital machines always let you down when there is too much clutter. With a Seafarer you can SEE the clutter - the brain/eye is a much better signal processor than we know how to code.

Of course a modern digital fishfinder is just as good.

How do you know both your head end units are faulty? I brought ours home and connected a condenser mic to the transducer and got enough of a reading from it to tell what was going on.

Think I'm going to have to renew the transducer - what a pain! the current one looks like its epoxied into the wooden hull.

Julian


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## skipbuono (Jun 19, 2014)

anybody still interested in seafarer3 info/discussions. it is a very good old unit and i like it. mine quit after 10 years,it was old when i got it. i'm looking to buy a working unit,or schamatics to repair one.
skipb


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## txg (Jan 30, 2013)

We're also still using it, works well. Unfortunately I don't have any schematics. We also got a Seafarer Log (Speedometer), but i've thrown it away as i couldn't get it to work.


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## skipbuono (Jun 19, 2014)

*Re: Seafarer 3 Depth Sounder txj*

thanks for the info. can't find any seafarer3 in the states. some on google uk ebay. don,t know if it's worth looking into uk. any body got any suggestions for a unit or schematics, or first hand repair on these units?
skipb


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## julianc (Apr 15, 2008)

I see lots on eBay and at boat jumbles in the uk. Still using mine and NASA still sell new compatible transducers. Still like it. I would buy one of eBay as long as I'd talked to the seller.


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