NASA duet

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NASA duet

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Mikenfi
United Kingdom
40 Posts

Posted - 14/07/2014 : 19:33:41
Hi we have a NASA duet which is not reading correctly. We see that someone has mentioned that NASA will fix the display. Slo that shouldn't be a problem, if that's the cause.

We would like to change the transducer, and wondered if anyone with a sabre has had any problems fitting an in hull transducer?

Thanks Mike and Fi

ianfr
United Kingdom
104 Posts

Posted - 15/07/2014 : 09:49:35
The in hull kit that NASA supply is fine, try several locations using blu-tac temporarily to find the best spot. Mine is located in the locker underneath the port quarter berth, next to the galley, and where you would sit at the chart table.

The hull is around a half inch thick there, as I found out when I fitted the log in the same general area. I have no issues with the echo sounder there and it was giving stable readings across the channel earlier this year. ( > 160ft)

The only problem I have, and suspect it is typical of modern echo sounders, is that it is nearly useless when you get down to about a foot or so to the soft mud that abounds round Tollesbury. Fortunately the fin keel makes quite a good plough

Regards

Ian

Kind Regards

Jo and Ian
Apogee, Tollesbury

kcalco
United Kingdom
58 Posts

Posted - 15/07/2014 : 20:52:15
Hi
Been here done it.
The transducer is a piezoelectric crystal and never goes wrong.
It will read open ciruit at all times.
The only thing that goes wrong is the cable and connections to the Nasa unit.
Replacing the cable is no problem but has to be 6.9M.
I got a Clipper unit which works perfectly with the old tranducer, fitted 30years ago.
I am moored in the Walton Backwaters where there is ample mud and have no problems reading down to .8m when i'm aground.
Moden sounders put out about 600watts and are far superia than older units.
Regards Ken
PS All connection have to be soldered (especially to the plug).

kcalco
United Kingdom
58 Posts

Posted - 16/07/2014 : 08:48:19
Hi
if you want to test the output from the sounder unit then put a transistor radio next to it.
Tune the radio to no station on MW and you should get a good strong tic tic from the radio. Move the radio to the tranducer end and it should be just as strong.
Ken

Mikenfi
United Kingdom
40 Posts

Posted - 24/07/2014 : 11:14:07
Thank you guys so much for the speedy replies. I have purchased a new depth sounder and will test this after my return from work in the next few weeks.

I was considering changing the cable on the old tranducer (which still clicks) but the cable seems to be permanently installed in the at this end. So a new one it is.

NPMR
United Kingdom
59 Posts

Posted - 01/08/2014 : 10:51:58
On my boat before my Sabre, I put the transducer in a tube glassed to the hull in the focsle. the tube was filled with olive oil and the top sealed. It read perfectly for all the years I had the boat (many) and meant that I did not have to make a new hole in the hull.

I have seen this mentioned elsewhere and so it seems to be a typical solution.

On our Sabre, we have the NASA transponder under the dining table on the starboard side and it seems to read OK down to about 0.5 feet! (After that, we are aground!)

kcalco
United Kingdom
58 Posts

Posted - 04/08/2014 : 18:07:19
Hi
Just thought i would post this tip for anyone having problems with there sounder.

Replace the transducer cable.

Cut cable close to the transducer and strip it back. Get satalite cable and strip end back. solder inners together and tape up. solder outers together. now bind with something like 15 amp fuse wire to screen out interfirance. tape over and slid a piece of hose pipe over the joint (about 8 inches) to keep it securlly in place. the overall lenght has to be 6.9meters. solder a good quality areal plug on the end and you could save yourself buying a new one.
As Paul has said elsewhere on this forum, the transducers are very reliable.
Do not try measuring transducer resistance, it will always read open circuit, as it is piezoelectric device.

Happy sailing.

Regards Ken

Mikenfi
United Kingdom
40 Posts

Posted - 21/09/2014 : 16:49:56
Thanks for all the help. I have also bought a handheld fish finder as a back up.
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