Depth gauge vs Chartplotter

[dave_and_dd]

So my raymarine depth instrument has stopped working (just shows dashes - I have the typical 2007 era depth, wind and AP which go through the seatalk1 to seatalk-ng converter to connect to the chartplotter). While I troubleshoot that I thought it would be a really nice idea to have a backup depth instrument.

So I was going to order a stand-alone gauge with an in-hull glue down transducer (had one in a previous boat that worked great).

then I realized my garmin 942xs chartplotter can take a transducer input....hmm...

So my question is:
Can I expect to get good depth readings if I hook up the xducer to the chart-plotter sonar? My point is, all the pages in the manual show how display is more of a fish-finder and can detect things in the water. All I want to know is depth of water. Note: I'm talking about just using the basic transducer, not the $1400 forward looking sonar, nor the side scan CHIRP stuff which it can do. (I'm cheap). Just want a number for depth reading.

Bonus question: how close in the hull can 2 transducers be mounted without interfering with each other. are we talking like: keep them 10 ft apart....or a couple feet is generally ok?

thanks for any insight
Dave in Charlotte Harbor

 

[BarryL]

Hello,

I have both a Raymarine ST60 depth, and a sonar transducer connected to my B&G Vulcan 7FS plotter. On my previous boat I had a Lowrance plotter / fishfinder and an old depth gauge (I forget the brand). I have 'shoot through' sonar transducers and through hull mounted depth transducers. The through hull transducers for the depth only display works very well and I can detect the bottom at least down to 160 ft (The deepest I have seen). The shoot through transducers loose the bottom at around 100' depth. Since I don't care about finding fish, and only about shallow water, that is fine with me.

For me, the advantage of the SONAR display is I can see the type of the bottom and see how quickly it's getting deeper or shallower. Knowing the bottom is sand or clay or mud makes anchoring easier.

Last bit - you can't have two sonar transducers work on the same frequency. My Raymarine is at 50HZ. My B&G can be at 50HZ or 200 HZ. If I select 50HZ then the raymarine doesn't work. So make sure they two are at different frequencies and then you won't have a problem.

Barry

 

[Tally Ho]

I just use the depth transducer on my Garmin CP.

Greg

 

[Terry Cox]

Our 1991 boat came with a Autohelm ST-50 depth through hull transducer that still works, albeit a bit funky at times. Installed a Garmin 178C Sounder in 2005 that uses a shoot through the hull transducer. The ST-50 used to read down to about 500 plus feet, but now maybe 250 due to some interference with the other transducer, I suspect. The Garmin reads 7-800 feet. The ST-50 is forward of the keel and the Garmin is back by the shaft strut. Both give me the readings that I need when waters get very thin during anchoring. The shoot through the hull transducer depends on solid FRP to get a good reading; no voids very important. Testing before making it permanent makes a difference in performance. The Garmin also has a fish finder that you can select or not.

 

[dave_and_dd]

Hey guys - thanks for that info. Sounds like the chart plotter interface is more useful than simply being a fish finder. As mentioned, seeing the type of bottom and the changes (trend) is useful stuff.

I'm leaning toward using the chartplotter with a xducer instead of a dedicated depth instrument as my new depth (until I get the original raymarine instrument fixed).

thanks,
Dave

 

[Tally Ho]

You can see a few different screen layouts on my Garmin Chart plotter in these shots...depth is always available to me...
upper right on this screen...


lower left on this one...


the screens on my Garmin are customizable, so I can move the depth info where I want it.

Greg

 

[Tally Ho]

And one of the cooler functions I found on the CP is the ability to show the system voltage...

so now I don’t have to guess or check the battery gauge at the Nav station.

Greg

 

[dave_and_dd]

Hi Greg, is that depth coming from a transducer directly attached to the garmin, or is a separate depth gauge (like a raymarine with its transducer) interfaced to the garmin?

Dave

 

[Tally Ho]

Hi Greg, is that depth coming from a transducer directly attached to the garmin, or is a separate depth gauge (like a raymarine with its transducer) interfaced to the garmin?

Dave

No, there is a transducer in the hull.

Greg

 

[MitchM]

My raymarine speed impeller went to alll dashes. I pulled it and cleaned off all the zebra mussels and it then worked fine....

 

[rpwillia]

Can you wire the ST50 directly up to the Garmin? I understand most of these are made by Airmar. Or, can you get a Garmin that fits in where the ST50 transducer is? At that point you could go with a Chirp transducer.

 

[dave_and_dd]

Ray - if you mean, can I wire the transducer from the st60 directly to the garmin? the answer is: "I don't know". They certainly are different wiring. the Ray airmar xducer has 3 wires, the garmin input plug is 8 pin. Plus, I don't know if the issue is with the ray instrument or with the xducer. Also note that the ray depth xducer is through the hull and not replaceable in the water.

my current plan is to go ahead and order a new in-hull xducer for the garmin. (even if/when I get the Raymarine depth working it's nice to have multiple instruments).

I've posed a question to raymarine - can I remove the depth instrument and send it in to be tested? If so, I could find out if the problem with the ray setup is xducer or instrument. Alternatively, I could spring for a new instrument (like a ray i50) and if the ray xducer is still good, be back working...


and to MitchM - the transducer is clean. It's not a bottom growth problem.

thanks guys - Dave

 

[rpwillia]

Ray - if you mean, can I wire the transducer from the st60 directly to the garmin? the answer is: "I don't know". They certainly are different wiring. the Ray airmar xducer has 3 wires, the garmin input plug is 8 pin. Plus, I don't know if the issue is with the ray instrument or with the xducer. Also note that the ray depth xducer is through the hull and not replaceable in the water.

my current plan is to go ahead and order a new in-hull xducer for the garmin. (even if/when I get the Raymarine depth working it's nice to have multiple instruments).

I've posed a question to raymarine - can I remove the depth instrument and send it in to be tested? If so, I could find out if the problem with the ray setup is xducer or instrument. Alternatively, I could spring for a new instrument (like a ray i50) and if the ray xducer is still good, be back working...

I know the ST50/60 transducers are based on SeaTalk which is their proprietary version of NMEA 0183, but I would suspect since AirMar likely makes it there is a combination of wires that are NMEA 0183 only (don't get me wrong - SeaTalk is nice as it just works all together). My ST60 transducer can be unscrewed and popped out and replaced with a cap (the cap is chained to the rig). Same for the speed wheel. It just seems worth it to ask Garmin it they have a transducer you could place in there. You could always leave the Raymarine transducer duct taped to the side if you wanted to keep it, but would have a bit nicer setup, especially if you went with Chirp.

I recently helped a friend who installed a new NMEA 2000 transducer on his boat to get his chartplotter to display depth on his chartplotter. Pretty slick set up. Another friend is considering radar as he wants to invade Maine this year by sea and it appears with NMEA 2000 you can easily integrate a lot of this stuff together.

 

[BarryL]

Hello,

Note that the older Raymarine gear, basically anything that is Seatalk, requires that the display unit be connected to the transducer. I believe that the display unit converts the signal from the transducer to seatalk and puts that data onto the seatalk network. I don't believe the output of the transducer (depth, speed, or wind) is NMEA0183 or Seatalk. I believe the output of the transducer needs to be converted to before it's put on the network.

For ST 60 Depth

And for ST 60 Wind

I don't believe the output the transducer is NMEA.

The newer transducers may be NMEA 2000 but the older ones are not. Anything SONAR that is CHIRP or high resolution will not be NMEA. Same with RADAR.

Barry

 

[rpwillia]

I am liking NMEA 2000 more and more. After looking at the drawing @BarryL supplied there are only 3 wires from the transducer, and I wonder if there is a way to hook those up to something to see if it is working.

 

[dave_and_dd]

Yes, I like the NMEA 2000 too. I currently have my seatalk depth, speed, wind and AP connect to a seatalk to seatalkNG converter and then those data get sent to the Garmin CP on the 2K backbone. That has been working fine (until the depth stopped). And the depth (only) is not showing on the st60 instrument so I know it isn't just the conversion to NMEA2K that's at issue.

BarryL - yes, that's correct, the signal coming from the xducer is not NMEA (anything) and so the xducer needs to be connected to an instrument to drive it and interpret the signal. However, both the raymaring st60 OR the garmin CP will drive and interpret the signal from a transducer. I wasn't talking about connecting the xducer thinking it was NMEA0183. Even if the older raymaring xducer would connect directly to the garmin, I don't plan to do that as it is an old xducer. I plan to get a new garmin xducer to directly connect to the garmin. Then troubleshoot the raymarine instrument issue.

and my raymarine xducer will NOT come out with the boat in the water. It is NOT removable like the speed transducer is.

Dave

 

[seadaddler]

I have 2007 H-36 with stand alone depth and speed instruments and also can get the depth and speed and also autopilot all work with my chartplotter thru NMEA on my older C-80 chartplotter.
Nick
I also upgraded the speed and depth for Sonar and more info on paddle wheel depth.

 

[jssailem]

Let's start.
A depth transducer is a device that converts variations in one energy form, into corresponding variations of another energy form.

I took an old transducer that was in the boat. My guess it was a 80Mhz unit from about the mid 80's. I connected it to a RayMarine iTC5 box.

Three leads from transducer.
Colors for the 2 leads are dependent on the transducer..
Positive to terminal 2. Negative to terminal 3.
And then powered up the iTC5. The box powered the transducer and received the depth signals in pulses. The box converted the pulses to SeatalkNG (183 messages) and placed the data on the backbone. I pick up this data on my Vesper XB8000 and transmit the data in the backbone to the iPad running an App that reader the data and shows it to me in a GUI (i.e instrument image) that I can understand. It shows depths up to 300feet then it reports garbage (signal too weak or taking too long to return from the bottom).

Yes you can use an existing transducer if you make proper connections (wire the system correctly) and can then translate the data into a usable signal (a black box) your hardware can display to you in a manner you can understand (your MFD).

Pretty simple really.

 

[dave_and_dd]

Hi thanks Jssailem, I know it is possible to connect a xducer without the raymarine instrument. My garmin chartplotter will take a xducer feed directly (wouldn't need the ITC5 box). IF I knew that the xducer could have an appropriate way to wire it's 3 wires into the 8 pin garmin connector - I could test the existing xducer with the garmin. sure, the ITC5 is one way to go, but buying a garmin xducer and attaching directly to chart-plotter is cheaper.

The real conundrum now is, none of this tells me whether the raymarine instrument or xducer is at fault (or even possibly the wire in between).

I contacted raymarine, they no longer will take an old instrument for evaluation to tell me if that's the issue (that's the easy part to take out). The xducer couldn't come out until the boat is on the hard, which is not happening any time soon. Did contact a marine electronics place and they would charge $100 just to test the instrument which seems a little excessive. (I need someone with a raymarine st60 laying around I could use to test!)

thanks, Dave

 

[jssailem]

Sounds like you need a dock friend with a ray marine system to take your display and plug in to their system to see if it works. That would be the easiest. Lowest cost.