Sounds like Borneo

[mico]

Back from Borneo after a flying visit to take possession of our new ketch. Installed new fridges which are now wired and plumbed with just the water cooling to be connected and the final circuit breaker to be installed. Discovered that shopping for parts there is a back alley affair with a wide mix of weird and wonderful characters and a frenzy of pointing, gestures and nods that could mean anything at all

On the test sail I noticed the depth sounder (integrated into the Garmin chart plotter) dropping out or going haywire when ever the engine was turned on. My first thought was that this might be due to interference with the transducer lead run too close to other wiring but I was told that this was a fairly recent occurrence. Lifted the hatch where they were located (paddle wheel & transducer) I noticed another transducer laying next to them with a lead running off under the floor. It looked like this transducer had been replaced but was still connected as when I pulled down the main nav station cover, I found it wired to a silva depth sounder display unit which was then in turn wired to the Garmin.

Would having two transducers close together (one in use and the other simply laying in the hold) but both still getting power, cause a signal variation?

Not being an electronics wiz and still coming to terms with the feast of components and wiring jammed behind the nav main board it's all a little beyond me and in such a remote location, I'm thinking about simply pulling out all transducers, disconnecting them and installing a new one (still in its box in one of the holds) and running that up to the cockpit totally separate to everything as a single stand alone display. I can then sort out integration when we get back to Oz with someone who knows what they are doing rather than me bumbling about. Does this make sense?

Fair winds,


Mico

[redbopeep]

David passes along that you may be getting noise from the alternator when the engine is on. Could be any number of things along the way (to the depth sounder) but corrosion in connectors, terminals, etc. Go through and check for corrosion and clean up everything.

You can get out your computer with a serial port--your NMEA 0183 signal will be able to be dumped to the computer (it's text) and you'll be able to tell if it's giving you something like um...depths. If all scrambled, then noise in the signal is likely.

Since it only happens when engine is on, the above is likely. If all the time:

If you have two depth transducers, you need to make sure they are running on different frequencies. Our FLS is different frequency than our DST. Can't recall the two different frequency bands, but you could look up each of your transducers and see if they both are running on the same frequency.

No, they don't tell you this stuff when you're buying the transducers either

Good luck!

PS--we like stand alone display rather than part of chart plotter. Our depth transducer runs to a CruzPro display inside that can be seen from cockpit. The FLS is in the cockpit and can be seen from there, of course. We note that the DSP is approx 30 feet behind the FLS. So, we often get two very different depths from the two different sensors.