AIRMAR DEPTH SENSOR WON'T READ OVER 100 ft.DEEP

I have roughly 6 yr old Airmar depth sensors on my Grand Banks. My Depth/Temp sensor is a smart B122. When I reach depths of over 100 ft, my screen blanks out even when I slow down to idle. It reads again fine at shallower depths but will not read depths over 100 ft. Sensor range is spec'd at 500+ ft. I cleaned the sensor but that did nothing. An Airmar tech guru says I should try a firmware update but that requires bringing in an instrument professional with a tester. Anyone have a similar experience like mine to give advice? Also, re: in-water sensor removal using the plug. I've never tried this before and I'm a bit timid about trying it myself. Is this easy for a mechanically inclined owner to do?

While it looks deceptively easy, I would prefer to have a diver hold something like a large sponge or folded towel over the hole. If it were me, I would pull it, plug the hole, and send the unit to Airmar. I'm sure they have a diagnostics bench to fully evaluate it. While the sensors aren't cheap, I need to know it's reliable.

As a funny coincidence, my boat is in the yard and this afternoon I bored a hole for a second transducer for my NMEA 2000 network. While coming North this spring, I had another boat follow me for a couple of days as their depth sounder had quit. While I do have 2 separate transducers, only one was on the network. Decided a second transducer on the network would be cheap insurance as it could be accessed by 6 different devices on the network.

Ted

We lost a depth sensor on our Raymarine system when we were in AK. The electronics shop, in Seattle, suggested that we plug in a replacement transducer. We paid for the shipping of a working spare that we plugged in and hung over the side. The system still didn’t work. We had to buy a new display but we didn’t have to replace the transducer or run/slpice new cables.

I had a similar issue where the depth sounder would work initially then it would start loosing the bottom. For quite a while it seemed to work most reliably in shallow water. My transducer is an older Airmar B44. I ended up at the same point as you regarding the need to locate a tech with the right equipment to troubleshoot the transducer in the water. I eventually went the other route and picked up a second transducer to hang over the side to test the display. I figured at worse case I would end up with a spare transducer. Bottom line it was a bad transducer and lucky me I just one left over from my testing.

On another note if your transducer is built similar to mine then the insert is just a paddlewheel that is used for speed measurement. The only way to pull the transducer is with the boat out of the water, and probably you will need a new faring block.

In my experience, and from the experience of others I have read, the "Smart transducers" are utter junk. If yours lasted 6 years you did well. Mine lasted about 2 years then about 6 months. The B122 is the long stem version, same as I had. That tube does not have the built in flapper than slows water flow. Only the plastic tube has that. These also go by the name of DT800, DST800, DT200, etc. Everyone gets their own name for the same thing.

twistedtree said:

In my experience, and from the experience of others I have read, the "Smart transducers" are utter junk. If yours lasted 6 years you did well. Mine lasted about 2 years then about 6 months. The B122 is the long stem version, same as I had. That tube does not have the built in flapper than slows water flow. Only the plastic tube has that. These also go by the name of DT800, DST800, DT200, etc. Everyone gets their own name for the same thing.

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With all do respect, I'm installing a DT800BV series transducer. The Bronze through hull does have the flapper (at least mine does).

Ted

So, which non-smart transducer will give good readings at shallow depths?

JESSEDIVER49 said:

I have roughly 6 yr old Airmar depth sensors on my Grand Banks. My Depth/Temp sensor is a smart B122. When I reach depths of over 100 ft, my screen blanks out even when I slow down to idle. It reads again fine at shallower depths but will not read depths over 100 ft. Sensor range is spec'd at 500+ ft. I cleaned the sensor but that did nothing. An Airmar tech guru says I should try a firmware update but that requires bringing in an instrument professional with a tester. Anyone have a similar experience like mine to give advice? Also, re: in-water sensor removal using the plug. I've never tried this before and I'm a bit timid about trying it myself. Is this easy for a mechanically inclined owner to do?

Click to expand...

Is it a NMEA 2000 transducer? If so, and if the nearest network is easily accessible, a replacement could take maybe 10 minutes or so, including dressing the cabling afterwards.

One of our transducers doesn't have the protective valve... so some water sloshes in. But it's a quick replacement, just needs clean-up afterwards. Plan your attack: learn what faces which direction, out with one hand, in with the other.

Ours (that one) went south starting last year, actually. Gave good readings, then false readings, then 3x false readings, then blank, then good again, etc. I think the plug on that one may have been a Maretron DST100, although old brochure says DST800. Anyway, our electronics guys said that product maybe had a built-in glitch from the beginning, although my own guess was that we may have been affected by a nearby lightning strike (cause our two radios went glitchy, too). Replaced the original with a new Airmar DST800, seems fixed.

-Chris