PDACPA wrote:
Dang! My knuckles are hurting from the rapping Bill gave me with the ruler! Hope I can type!
Having survived catholic school I would never subject anyone else to the ruler. Or a pointer, or a thrown eraser. Ah, childhood memories.
Sounds like you've got a good handle on the issues involved. If you can dig up some specs on the depth stuff you could use that to be sure about what sort of wiring is necessary for it. You want to make sure to be using heavy enough gauge wire to carry the necessary load over the distance. And that the rest of the circuit supplying power to it is also up to the job. There is the possibility that the depth stuff (which I assume is just the gauge and the sensor, right?) isn't working properly. No amount of correct wiring will overcome a defective piece of gear. Once you know what load it requires (from the specs) you could confirm it's not exceeding that amount with an ammeter (which measures load).
And if you're moving toward using a chartplotter (and presumably a new depth sender) then it might be a moot point. You'd do well to set up a whole new circuit for that gear anyway. That way you'll know everything's set up properly from the get-go. And if you go with network sensors you could replace that existing gauge with a digital one. The new digital gauges can display lots more data too. Like also showing GPS or even fuel consumption info (if you add fuel flow senders). I've got a lowrance gauge with flow sensors to see fuel data, but it also picks up the GPS, depth and water temp data from the other sensors on the NMEA network.