ID my depth transducer

My trawler has an ancient Furano LS 6100 display hooked to a transducer - pic attached. The display shows accurate depth and a steady 18kts of speed at the dock.

I snagged a Raymarine Axiom 7 from Defender for $400 & would love to ditch the Furano stuff and display depth on my fancy new chart plotter.

Can anyone tell me what I’ve got? Cable has “Airmar Transfucer Cable” printed on it but no other labels. I’m too chicken to pull it & couldn’t find any identifying marks on what is shown.

I’m getting my bilge cleaned on Monday and haven’t finished up my cable management project yet so don’t judge!

Check the other end of the cable to see if there is a marking there. It looks like my B744 transducer. Try Airmar for more info.

NWSeadog said:

Check the other end of the cable to see if there is a marking there. It looks like my B744 transducer. Try Airmar for more info.

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Thanks - couldn’t find a cable tag but will check again tomorrow.

All I really need is depth - might it be easier to get a Raymarine shoot through unit that plugs right into my Seatalkng backbone?

There is usually a tag on the display end of the cable. Airmar makes the transducers for just about every manufacturer out there. They look the same only the connectors are different.
Airmar has an OEM Cross Reference. Can you also post a picture of the connector?

I had a similar experience trying to ID an old one.
Airman indicated they mark the xducer end.
I found a tag on mine about 6ft from the xducer hidden from view.

NWSeadog said:

Check the other end of the cable to see if there is a marking there. It looks like my B744 transducer. Try Airmar for more info.

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Thanks! Found it (6’ from the plug end) and you win the prize!

So now the question is how to get it onto my seatalkng backbone. Best I can tell I need an ITC-5, correct?

Axiom can have built in sonar, or not. Depends upon the model. If it's built in it is setup for either CHIRP, downvision, or realvision transducer. If it's not built in you might need a CPxxx series sonar module and a Raynet cable. Raymarine makes a dizzying array of adapter cables.

Frankly I think it is easier and cheaper to just buy a new transducer and install it in the existing hole. Or epoxy the old hole and cut a new one. (2 3/8") Total cost of transducer is $150 (chirp) and you can get 0, 12, or 20 deadrise.

SoWhat said:

Axiom can have built in sonar, or not. Depends upon the model. If it's built in it is setup for either CHIRP, downvision, or realvision transducer. If it's not built in you might need a CPxxx series sonar module and a Raynet cable. Raymarine makes a dizzying array of adapter cables.

Frankly I think it is easier and cheaper to just buy a new transducer and install it in the existing hole. Or epoxy the old hole and cut a new one. (2 3/8") Total cost of transducer is $150 (chirp) and you can get 0, 12, or 20 deadrise.

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Thanks! I don’t need any of the fish finding stuff, just a plain old number for depth. I’d much rather spend $250 on an overpriced converter (ITC5) than haul the boat for another through hull. Swapping sensors is fine but it seems whatever I buy I’ll still need the ITC5? I don’t see anything that plugs right into a Seatalkng backbone. Would love to be wrong.

does your Axion have built in sonar?

Airmar makes a splice box for when you have to cut the cable during the install. Maybe you could buy a cable for the Axiom and splice it to the transducer. You should call Airmar and ask them.

SoWhat said:

does your Axion have built in sonar?

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No I don’t think so. Hasn’t arrived yet but it was really really cheap.

I’ll give Raymarine a call tomorrow I think.

When I purchased my new Garmin chart plotter, I was very confused as to which transducer would work best for my needs. As suggested above call Airmar. They are very helpful and will steer you in the right direction.

Airmar advised me to call Raymarine, which advanced me to "tier 2 technical support" then put me on hold forever before the line was disconnected. I submitted a question online to them as well.

I'm amazed that this could be so complicated. Makes me want to just get a $100 shoot-through Hummingbird and glass over the through hull next haul-out.

You can put an Airmar P79 shoot through the hull transducer that directly feeds an nmea 2000 backbone. No hole in the hull so no haul out. Assuming the raymarine uses nmea 2000.

High Wire said:

You can put an Airmar P79 shoot through the hull transducer that directly feeds an nmea 2000 backbone. No hole in the hull so no haul out. Assuming the raymarine uses nmea 2000.

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Not if the mfd is not equipped with sonar processing circuitry

SoWhat said:

Not if the mfd is not equipped with sonar processing circuitry

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I don't have RV or DV in the unit - so I think I can't just hook a transducer into SeaTalkNG; I think I need an ITC-5 or something that can interpret the signal from the device. Tried Defender & they couldn't help either.

socalrider said:

I don't have RV or DV in the unit - so I think I can't just hook a transducer into SeaTalkNG; I think I need an ITC-5 or something that can interpret the signal from the device. Tried Defender & they couldn't help either.

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Well something have to generate and process the sonar signal. If you don't have a transducer connector on the back of the mfd then the mfd is not capable of generating a signal. If it not internally supplied, then you would need an external sonar module. Guessing a CP470/CP570 Sonar module as they are the only 2 that will work with Lighthouse III. The module communicates with the mfd via Raynet.

If your mfd does has a chirp transducer connector then it is generating a signal. You would simple need an adapter to convert the Raymarine 9 pin to the airmar 7 pin (or whatever it is) Note the Axiom may be putting 1000W out and your airmar may only be 500W. SOmething to check on.

If you are stilling using Lighthouse II then you may have more options. I am not that familiar with Axiom so I would recommend contacting a Raymarine installer.

SoWhat said:

Not if the mfd is not equipped with sonar processing circuitry

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The P79 just outputs an NMEA digital depth sentence reading about 1/second. It is a number sent to the mfd just like speed or COG. Not a fishfinder graph type video display. I have a P79 NMEA 0183 type now connected to my Garmin 5212.

High Wire said:

The P79 just outputs an NMEA digital depth sentence reading about 1/second. It is a number sent to the mfd just like speed or COG. Not a fishfinder graph type video display. I have a P79 NMEA 0183 type now connected to my Garmin 5212.

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Yeah I just want the depth number. Seems I should be able to buy a Raymarine brand P79 for $150 or so and plug it into the SeaTalkNG network. But damned if I can find anyone to confirm that. Still baffled at why it's so hard to figure this out.

socalrider said:

Yeah I just want the depth number. Seems I should be able to buy a Raymarine brand P79 for $150 or so and plug it into the SeaTalkNG network. But damned if I can find anyone to confirm that. Still baffled at why it's so hard to figure this out.

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OK finally got through to Raymarine. Here's the answer in case anyone wants to know:

Not possible to interface a depth transducer directly to MFD (as So What stated) unless it's equipped with a sonar interface. Instead, I'd need to plug it into an I40, I50, or I60 depth display, which in turn could be interfaced via SeaTalkNG network. So a $350 display plus a $150 transducer minimum.

Tempted to just get a Hummingbird shoot through for $100 and be done with it. Something to be said for simple, non-integrated systems I think.

socalrider said:

OK finally got through to Raymarine. Here's the answer in case anyone wants to know:

Not possible to interface a depth transducer directly to MFD (as So What stated) unless it's equipped with a sonar interface. Instead, I'd need to plug it into an I40, I50, or I60 depth display, which in turn could be interfaced via SeaTalkNG network. So a $350 display plus a $150 transducer minimum.

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Not positive but you may need an I70 in order to calibrate depth. I don't think Raymarine tech passed on that little tidbit. I decided to stay with older aXX series. Axiom with LH III seemed to obsolete a number of prior configurations and it won't share a network with LH II devices. With Axiom you're all in or all out. I'm out.

SoWhat said:

Not positive but you may need an I70 in order to calibrate depth. I don't think Raymarine tech passed on that little tidbit. I decided to stay with older aXX series. Axiom with LH III seemed to obsolete a number of prior configurations and it won't share a network with LH II devices. With Axiom you're all in or all out. I'm out.

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She said the i70 would be necessary for calibration if I used an ITC-5 to interface my existing sensor, but i40, 50, 60 didn't need the I70. i40's cheapest but, insanely, needs a $90 Seatalk to SeatalkNG converter to interface to their current standard. But who knows... she could be wrong!

This stuff drives me bonkers. Honestly the only reason I got the MFD was 'cause I needed a second control station for my EV150 AP - it was on sale for cheaper than a $500 P70r control head & for $380 I got a redundant chart plotter & GPS. I figured adding depth would be a piece of cake.

socalrider said:

This stuff drives me bonkers. Honestly the only reason I got the MFD was 'cause I needed a second control station for my EV150 AP - it was on sale for cheaper than a $500 P70r control head & for $380 I got a redundant chart plotter & GPS. I figured adding depth would be a piece of cake.

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I went through the same process. Ended up ripping my old transducer out. Simplest and cheapest solution. Raymarine spends a lot of R&D money on UI, but compatibility of older versions seems to be an afterthought.

SoWhat said:

I went through the same process. Ended up ripping my old transducer out. Simplest and cheapest solution. Raymarine spends a lot of R&D money on UI, but compatibility of older versions seems to be an afterthought.

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What did you end up going with?

Now, I'm fairly sure that your RM MFD will accept and display all the most commonly used data from NMEA 2000 devices, in which case you just need an N2K Smart Transducer, which is a complete depth sounder that just outputs the depth as a number. You may or not be able to configure the transducer - e.g., set keel offset, with your MFD but that could be done by plugging it into somebody else's system with an N2K display.

EngNate said:

Now, I'm fairly sure that your RM MFD will accept and display all the most commonly used data from NMEA 2000 devices, in which case you just need an N2K Smart Transducer, which is a complete depth sounder that just outputs the depth as a number. You may or not be able to configure the transducer - e.g., set keel offset, with your MFD but that could be done by plugging it into somebody else's system with an N2K display.

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Interesting! So I could plug a NMEA2000 P79S into the MFD N2K port and get an actual depth number (transducer to seabed)? If that’s the case calibration isn’t too critical.

Looks like the smart version is $275 for n2k or $350 for Seatalkng tho. Maybe better to bite the bullet and get the i50 with the dumb transducer for $450 at that point.

If I could get an n2k in hull for $100 or so I’d go that route.

That's correct. Check the manual about configuring N2K inputs and data displays. Also check about the MFD's power capacity for the N2K buss, an N2K power Tee might be required, two Tee's, two Termination Resistors and a cable will be required. If the MFD will configure the N2K device I don't think there's anything the STNG will have over N2K.

Update: I finally got through to some folks at Raymarine and Airmar who knew what they're talking about. My old B744V's cable can be cut and spliced into an ITC-5, which will convert depth/speed/temp to SeatalkNG and display them on my Axiom 7 MFD and P70rs autopilot control head. I went ahead and ordered the ITC-5 from Defender For about $230. Seems like the best solution; hopefully it works!

socalrider said:

Update: I finally got through to some folks at Raymarine and Airmar who knew what they're talking about. My old B744V's cable can be cut and spliced into an ITC-5, which will convert depth/speed/temp to SeatalkNG and display them on my Axiom 7 MFD and P70rs autopilot control head. I went ahead and ordered the ITC-5 from Defender For about $230. Seems like the best solution; hopefully it works!

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Quick update: The ITC-5 solution worked. Phew! Ripped out a ton of old wiring and now have a nice clean install using the existing transducer. Very satisfying.