Help me identify these transducers - 340 Da

boatrboy

Well-Known Member
Oct 3, 2006
1,828
Orange, CT
Boat Info
2006 340 Sundancer
Engines
Twin 8.1 Horizons with V-Drives
2006 340 Sundancer (new to me)

I have a Raymarine C-80 and the smart craft sc5000. I keep getting an erratic “low depth” alarm. I started researching more and see I have these removable transducers. I also don’t get any depth reading on the c-80. I am not sure if it’s a configuration issue or a bad sensor. They appear to be airmar sensors as I can see on one of the wires it has airmar printed on it.

There are two plugs attached to one of the transducer which are for the “daring” I guess to remove the sensors for cleaning. One seems different than the other.

So can you help me identify which sensor does what?

I am guessing the low level alarm is crud on the sensor but hoping for some input here.

Mark
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Yes, those are your transducers. 1 is depth the other speed and temp. I think. The transducer plugs are what go in place when you want to remove them. I never did it and I heard it can be a bit exciting!
 
2006 340 Sundancer (new to me)

I have a Raymarine C-80 and the smart craft sc5000. I keep getting an erratic “low depth” alarm. I started researching more and see I have these removable transducers. I also don’t get any depth reading on the c-80. I am not sure if it’s a configuration issue or a bad sensor. They appear to be airmar sensors as I can see on one of the wires it has airmar printed on it.

There are two plugs attached to one of the transducer which are for the “daring” I guess to remove the sensors for cleaning. One seems different than the other.

So can you help me identify which sensor does what?

I am guessing the low level alarm is crud on the sensor but hoping for some input here.

Mark
View attachment 129943 View attachment 129944 View attachment 129945
Same boat - similar issue. The sensor in the middle of the keel is for depth and sea water temperature and the the one that is offset to the starboard side is the paddle wheel for speed. I think the replacement sensor for the depth/water temp is now 79-8M0122506 which replaced p/n 79-8M0075630.
As far as replacing while in the water, there is supposed to be some sort of "flapper" to reduce the water when you remove the thing, but I don't have the "stones" to try, so I'll wait until I pull the boat before trying to replace.
 
Same boat - similar issue. The sensor in the middle of the keel is for depth and sea water temperature and the the one that is offset to the starboard side is the paddle wheel for speed. I think the replacement sensor for the depth/water temp is now 79-8M0122506 which replaced p/n 79-8M0075630.
As far as replacing while in the water, there is supposed to be some sort of "flapper" to reduce the water when you remove the thing, but I don't have the "stones" to try, so I'll wait until I pull the boat before trying to replace.[/QUOTE
Thanks very much Wind.
I looked up the p/n and it appears that this is a Mercruiser part. So is the C-80 reporting the depth based on this transducer? My C-80 doesn't report any data for depth when I run through the screens. Should it? Do you know if they (sensors) are both Mercruiser? The one on the port side (1st and third picture) says airmar on the cable. (I assume you meant port not starboard :)). So that sensor is for paddle speed. Where does it show up?

BTW - I watched several YouTube videos of people pulling the sensors out with boat in the water, but not for the faint of heart like me:)
 
On mine, the depth/temp only shows on the gauges and the paddle wheel operates the speedometer. The C80 gives a much better reading on speed (i.e GPS). I don't think the C80 will show depth with this transducer. Both are made by Airmar but you cannot purchase from them, only Mercury.
 
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On mine, the depth/temp only shows on the gauges and the paddle wheel operates the speedometer. The C80 gives a much better reading on speed. I don't think the C80 will show depth with this transducer. Both are made by Airmar but you cannot purchase from them, only Mercury.
Thanks - wondering if any other 340 owners pulled the sensor :D
 
I added a separate transducer and sounder module to my E-80 classic to get depth charts and use the fish finder feature
 
On mine, the depth/temp only shows on the gauges and the paddle wheel operates the speedometer. The C80 gives a much better reading on speed (i.e GPS). I don't think the C80 will show depth with this transducer. Both are made by Airmar but you cannot purchase from them, only Mercury.
Update - I have removed vhf and gps as I venture installing new stuff.

I have the std horizon gx2400 with ais receiver and need to cut the dash for this, and installed the nema 2000 network already.

Gps will be ordered shortly and radar will have to wait until next year.

So my question is on the c-80 I removed there is a three wire plug that says SeaTalk. It’s attached to a multi-wire cable (like a white phone cable). Is that where my gps gets depth readings? I see no dsm, at least under the dash.

Wind- did you replace your depth sounder yet? Did you have a DSM?

I plan on using a new sounder and running a nema line into the er, but I’m curious in these wires. I’m hoping a new sounder will be a direct fit into my housing…
 
if I remember correctly it goes to the sea talk antenna ? Or black black under dash
follow the cord
Depth transducer has to be replaced
Mine required a new hole
 
Thanks - wondering if any other 340 owners pulled the sensor :D
I pulled one in our 2003 420DA with the boat in the water. The older models do not have a flapper. There are basic sizes. Not sure what they are, but the one for speed and temp is smaller in diameter than the one for depth. Speed and temp was up near the bulkhead at the front of the ER and the depth one was in the rear bilge.

I installed a DTS 810 which has speed, temp, and depth all in one. It is bluetooth and connected with my phone as well. Supposedly, you can back off and unscrew the cap and pull the old one out. Mine would not budge. Had new transducer in my hand, along with a a cone shaped foam plug in case of an issue. Diver and I had signals planned out by knocking on the bottom of the boat. I sent him down with a 1" x 6" piece of dowel and a hammer. I unscrewed the cap, he tapped on it from underneath very gently, and the old one moved upward several inches. I was able to pull it the rest of the way out and shove the new one in. When I pulled the new one out, placed my hand over the housing, removed my hand, and pushed the new one into place. The whole thing lasted less than maybe 15 seconds and I had maybe a cup of water in the bilge. Nervous going in, but would do it again in a heartbeat.

Bennett
 
So what I’m trying to figure out is where is my vessel(1.5 older) getting depth readings from since I see no wires separate from the main harness. If the sea talk wires I see are the gps antenna, which seems logical as the main plug in the c-80 shows a pin out with nema’s, is my original transducer wired to the engine harness? I have not entered the bilge yet to follow the wiring, but for those who replaced their transducer, is this where it plugs in and gets its power? Wiring schematics refer to a note I can’t find.

I ask because if I have to keep my stock transducer i am assuming it will still work on the vesselview and just not on the new Garmin.

I really want to install the newer airmar without speed (don’t want to deal with the paddle) but I’m hoping it fits in my original sleeve. I think the one negative is that the depth would only show on the gps, not the vv if I upgrade to the airmar since my Vv in not nema 2000.

Forgot to mention, boat is on land for the winter so now is the time to do this..

Thanks for any light you can shed
 
I added a new one for this reason
Unplug them one at a time at the dash and you’ll see which features you lose
 
Also the new one didn’t fit in original sleeve anyways
 
I added a new one for this reason
Unplug them one at a time at the dash and you’ll see which features you lose
Thanks Dr.

Can you elaborate? I don’t quite follow - what reason? Did you do the job yourself or have it done? My dash is completely apart so no testing now. Can you answer my questions about the vv and tell me which unit you installed?

Tia
 
So what I’m trying to figure out is where is my vessel(1.5 older) getting depth readings from since I see no wires separate from the main harness. If the sea talk wires I see are the gps antenna, which seems logical as the main plug in the c-80 shows a pin out with nema’s, is my original transducer wired to the engine harness? I have not entered the bilge yet to follow the wiring, but for those who replaced their transducer, is this where it plugs in and gets its power? Wiring schematics refer to a note I can’t find.

I ask because if I have to keep my stock transducer i am assuming it will still work on the vesselview and just not on the new Garmin.

I really want to install the newer airmar without speed (don’t want to deal with the paddle) but I’m hoping it fits in my original sleeve. I think the one negative is that the depth would only show on the gps, not the vv if I upgrade to the airmar since my Vv in not nema 2000.

Forgot to mention, boat is on land for the winter so now is the time to do this..

Thanks for any light you can shed
The C80 requires a separate module to use a transducer for depth. It is a gray box and the best one for the C80 is a DSM300. That box gets plugged into the back of the C80 and the transducer gets plugged into the side of the DSM300. It has separate power, but assuming the DSM is powered, you will see a moving sonar symbol on the top of your C80 screen when it is powered on (and you will have sonar of course). But if you are seeing a low depth, then presumably you have a DSM. The DSM300 had a reasonably high failure rate, but if you have a good one, it will be good.

You can get used DSM300’s on EBay all the time. There are a lot of transducers that work with the DSM300. If you don’t need 500ft depth then a Raymarine P79 can be glued into the hull and will work well if it’s put in a good location.
 
To drill down on what’s actually installed, follow the wire and locate the wire tag. Then no guessing.
 
I had the yard add the new transducer
I added 2 simrads not a vv
 
I agree I will drill down in the ER and pull the sensor to get dimensions and find where it is wired. I am confused because there is no white tag that I can see on the sensor AND - everything I read says there is a DSM but my schematic doesn't show this nor did I find it when I ripped the dash apart. Could it be in the ER? I don't ever remember seeing depth on the C-80 only on my VV. I checked my survey pictures and the depth reading was 0 on the C-80, which is why I ask does the VV get its depth from the engine wiring harness?

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The white tag was on the er side of my cables
And where installed in boat as the schematic
 
I agree I will drill down in the ER and pull the sensor to get dimensions and find where it is wired. I am confused because there is no white tag that I can see on the sensor AND - everything I read says there is a DSM but my schematic doesn't show this nor did I find it when I ripped the dash apart. Could it be in the ER? I don't ever remember seeing depth on the C-80 only on my VV. I checked my survey pictures and the depth reading was 0 on the C-80, which is why I ask does the VV get its depth from the engine wiring harness?

View attachment 158970
The DSM could be behind the dash. On my boat it’s under a cockpit seat but it was installed by the prior owner not Sea Ray.
 

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