Thanks to all. I suspected that the device had reached a state of electronic senility. It sounds like a replacement is in order. - r
12-22-2009 09:11 AM
I had that same Navico unit on an earlier boat. This typically happens when the batteries are not fully charged, but it also gets worse with the age of the unit and eventually it was that problem which led me to replace my Navico with a newer unit. I will say that Navico used to have great customer support. For some minimal feee they would recondition any unit. Of course that was about 20 years ago and Navico has changed names and owners so it may be different today.
12-22-2009 08:57 AM
The sound impulse travels around 4,870ft / second ( temp dependant). If the displayed dept is creeping a lot, it sounds like the internal clock reference is drifting. ~4.8 ft per milisecond.
12-21-2009 07:01 PM
Poor timing and really big tides???
Probably not. Depth finders are just sonar echo systems that measure the time it takes the pulse to get from the sender to the sea floor and back. What you describe sounds like an electronic problem and is probably harder to fix that to replace with a much newer model.
Toss it and invest in a new one.
12-21-2009 04:28 PM
Depth Gauge Question
I have an old Navco 200 series depth gauge on my even older Catalina 30. When I first turn it on, it registers the correct depth – about 12’ in my slip. After a few minutes the indicated depth begins creeping slowly upward until it shows around 120 feet. Then it begins to slowly creep back downward to the correct reading, whereupon it begins the whole cycle over again. Can anyone offer any insight as to a probable cause/cure for this behavior, or a source for support for these old Navco sets?