Seafarer 3 - whats the norm?

[Engage]

On Saturday I sailed on Windermere for the first time with my 19 footer after a good deal of fixing up. Hoorah! With the boat came a Seaferer 3 that appeared to work i.e. the indicator span and the LED lit up. However, when on the water, the Seafarer failed to give indication of depth other than as indicated during a bench test with the transducer disconnected. Just a short flash showing about 1 foot. It shows the same depth on or off the water and whether or not the transducer cable is plugged in. I would have thought that without the transducer plugged in the unit would show a maximum depth as there is no echo. Can some one tell me what the normal display on a Seafarer 3 is out of the water with and without the transducer plugged in? This may help me diagnose the problem as I have no manual.

Many thanks.

 

[VicS]

I've got the manual but it is on the boat at the moment. I do do not recall anything that will answer the questions you have asked though.

Basically you switch it on to which ever range you want. Feet or fathoms in old money or metres or metres X6 on the new fangled metric ones. You should be able to see and hear the gubbins inside whizzing round and you'll get a flash at about the zero mark. Then you increase the sensitivity setting with the other knob and you should see a flash that corresponds with the depth. (If you increase the sensitivity further you will eventually get a second flash at double the depth as the signal rebounds off the bottom of the boat and back again.)

If you do not get a reading check the coax connection at the back clean it and make sure the cable is not damaged. If it is damaged cut the old moulded plug off and fit a standard television aerial plug but do not shorten the cable more than necessary.

Check that the transducer is mounted in a reservoir of castor oil on the inside of the hull (I assume it it is not mounted through the hull) There must be sufficient oil for there to always be oil between the face of the transducer and the hull with no air bubbles but one would normally cover the head. The transducer should be mounted close to the hull but it is not critical.

Also inspect the cable for damage along its length. If damaged I guess the solution is to cut the minimum out and rejoin with TV coax connectors (Either a plug and and in line socket or two plugs and a connector)

I hope one of those is the cause of your problem.

However you do not seem to understand the principle. You get a flash at zero (Well between zero and 1 foot) as that is when a pulse is sent out. When that pulse returns after bouncing off the bottom you get the second flash that indicates the depth. No signal being returned means you do not get the second flash. Not question of the maximum range, infact if I am in 70 feet of water with the thing on the 60 feet range The returning echo will show up on the next revolution of the revolving thing at the 10 feet mark (provided the sensitivity is turned up high enough.

Thats a point the deeper the water the higher the sensitivity has to be set to get a reading.

BTW the unit can be connected to an external 12 volt source (mine is ) and can infact accept higher voltages upto 24 volt (maybe higher). If battery operated it will continue to give a correct reading on the fathoms range even when the battery starts to fail. Discrepancy betwen the ranges indicates a failing battery.

 

[Engage]

Ahhh! Having not seen this work before I don't know how it is supposed to indicate depth. I assumed that the light would be on for the duration between ping and echo.
So it would seem that the unit is not flashing in response to the echo. In that case I would suspect the transducer end of things. I had already put a new plug onto the coax. I just didn't want to remove the in-hull mounting if it was the main unit at fault. I can't think of a simple way to emulate the echo electrical pulse so I guess I will have to chisel off the transducer from the hull.
Many thanks to VicS.

 

[VicS]

[ QUOTE ]
so I guess I will have to chisel off the transducer from the hull.


[/ QUOTE ] Oh no its been bonded on?

You wont get it off without wrecking it. Some makes that had little retangular transducers were bonded on but the normal method for the Seafarers , which had a transducer about 1½" diameter by 1" deep on the end of a treaded tube that the wire went through, was to mount them in a plastic tube, containing castor oil, that was bonded to the inside of the hull.

I would not try getting it off unless it has been stuck on with something soft, eg silicone in which case a nylon monofilament fishing line or cheese wire pulled underneath it might work. It would be better to leave it until all other posibilities are exhausted.

Make sure you have fitted the new plug properly, no shorts and a good connection to both conductors (Centre one preferably soldered) If you could find someone with a similar unit you could get them to try yours, or to try theirs on your transducer.

 

[oldharry]

Hang on a mo before you start attacking things! Did you turn up the Gain control? If not, you will not get anything - a bit like the volume control on the radio.

What should happen in shallow water is that at low or zero setting of the gain control there is no second flash. as you turn it up you will get the depth reading flash, then as you continue to increase the gain you will get more and more flashes all round the dial until the original one is completely obscured.

Its called an 'Echo Sounder' because it is listening - literally - to echos. If the original sound is too quiet (gain right down) it cant hear or respond to the echo. Turn it up to the right level it hears the echo. Turn it up too 'loud' and the echos go bouncing around all over the place and confuse the signal.

The only way to bench test is to connect the transducer and put it in the top of a rainwater butt or similar. If the transducer is not connected all you can see is that the set is producing the intial 'ping' - it wont tell you whether it can also hear and register the return echo.

 

[VicS]

[ QUOTE ]
Did you turn up the Gain control

[/ QUOTE ] I thought I explained that, except that I called it "sensitivity", not well enough though I guess. [ QUOTE ]
The only way to bench test is to connect the transducer and put it in the top of a rainwater butt

[/ QUOTE ] that's a bit difficult when the tranducer is bonded to the hull!

 

[Guest]

The old LED Seafarers ... I have a 5 and a 3 ..... they shouldn't give any depth flash if a transducer is not connected ... one of mine in fact doesn't even give a zero flash until transducer is connected.

I would consider that you may have a problem with connection of maybe transducer is dead ...

I've heard of test rigs if tubes of water - but haven't seen one ... I tried in a large oil drum - but that failed ... I think because of signal bouncing around in the drum !! But it worked when tranducer hung of the pontoon ...

It's worth noting that I couldn't get it to read reliably below 6 feet ... my pontoon is about 3feet depth and the signal apperaed to be bouncing - giving repeated flashes at multiples of the depth ... turning down the gain to get a true 3 feet reading ... flash dissapeared before I could remove the repeats ..

Suggest you ask if anyone else can connect their transducer to your display ... Seafarer 3 can run on batterys as well - so you can carry it to another boat to test. Any standard NASA / Echo-pilot etc. transducer will work with it ...