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Has an Airmar ultrasonic Speedo put in originally. Total piece of junk although a great idea as there are no spinning paddles. Replaced it twice in as many years. Flipped to the 800,and fine since.
 

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You could also leave the old one in (and forget about it) and install a shoot-thru-hull transducer in another location.
You can find solid glass w/o core.
Installation is dry and fairly easy....no hole.
 

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You could also leave the old one in (and forget about it) and install a shoot-thru-hull transducer in another location.
You can find solid glass w/o core.
Installation is dry and fairly easy....no hole.
He's looking for a speed transducer, not depth.

Mark
 

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I'm not ware of any chartplotters that will transmit data on to the network like this. Generally you have N2K enabled devices such as depth/speed transducers, air temperature/pressure sensors, wind instruments, etc, which connect to the NMEA2000 network and transmit data. Then you have other N2K enabled devices such as chartplotters or data display units that connect to the network and read data from it to display.
Thought about this some more and maybe this is a better answer.

On an N2K network there are some devices that generate and transmit data like fathometer, wind, speed, etc. These cannot receive anything as they are dumb transmitters and don't need any other data anyway.

Then there are devices that receive data like chart plotters, AP brains, etc. but are smart devices and can also transmit data like a plotter sending waypoints to an AP brain. This I have verified with my setup.

So once a device that can send/receive data is connected to the network I believe all the information that device has is then available on the network for any other device that can receive it.

Another example, my Simrad AP compass is a dumb device that transmits only but the data from the compass is received and used by my Garmin plotter and the Simrad AP computer.
 

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All N2K enabled chartplotters I am aware of can also retransmit received N2K data on a network (or onto another separate network). So can other devices such as some AIS transponders, small MFD's, etc. Many are also NMEA200-NMEA0183 translators. Some even retransmit and translate over wifi.

There is no need for the transducer to plug directly into anything - just connect it to the network backbone at the most convenient place. This avoids the need to retransmit any data, unless one wishes to bridge to another network.

Mark
 

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All N2K enabled chartplotters I am aware of can also retransmit received N2K data on a network (or onto another separate network). So can other devices such as some AIS transponders, small MFD's, etc. Many are also NMEA200-NMEA0183 translators. Some even retransmit and translate over wifi.
Thanks. That confirms my admittedly limited N2K experience.


There is no need for the transducer to plug directly into anything - just connect it to the network backbone at the most convenient place. This avoids the need to retransmit any data, unless one wishes to bridge to another network.

Mark
Assuming an N2K transducer. In my case my transducers (speed and depth) are not and have to plug into the Raymarine Bidata display. I believe that was also the case with my old Garmin. So in that case the transducer(s) would have to plug first to the plotter or MFD which would then have that data on the backbone. Yes?
 

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What I'm looking for is a thru-hull speed transducer that will send data onto an NMEA 2000 network so all my instruments can use it. Preferably it would 1.25" diameter to fit in the hole from the old (no longer functioning) device.

On the surface, if anyone can point me to a model that fits that need, I'd be eternally grateful.

On a deeper level, I'm wondering if it's just me, or is it insanely difficult to find information about this stuff? Looking at the advertisements, they say nothing about mounting dimensions or even the data technology in use. Especially with the data technology, it's frequently some proprietary protocol that may or may not be NMEA 2000 compatible.

Maybe I'm just impatient or really bad at research ... but it feels like I spend an inordinate amount of time trying to find out important bits of information about the equipment I'm considering buying. Is it just me?

If you don't want to replace the thru-hull fitting then you'll really need to know what is on the label/tag at the transducer end of the cable in terms of model/part #.

With this data you can then go through any legitimate marine electronics dealer/installer who has a Gemeco account, and order the correct transducer to fit in that thru-hull.

The current Gemeco catalog is 671 pages long so without the correct part numbers you're shooting at darts blind folded. Gemeco is the wholesale/distribution arm of Airmar.
 

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If you don't want to replace the thru-hull fitting then you'll really need to know what is on the label/tag at the transducer end of the cable in terms of model/part #.
If he wants a transducer that directly produces NMEA2000 output, then there are only three choices (ST800, ST850, DST800), and none will fit a 1.25" thruhull. It may be possible to use a non-N2K transducer connected to a converter box of some sort, but that seems a kludge way of doing it.

Edit: 4 choices counting the ultrasonic transducer.

Mark
 

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If he wants a transducer that directly produces NMEA2000 output, then there are only three choices (ST800, ST850, DST800), and none will fit a 1.25" thruhull. It may be possible to use a non-N2K transducer connected to a converter box of some sort, but that seems a kludge way of doing it.

Mark
Yes a converter box works but it is indeed a kludge.

Since I installed new speed and depth transducers not that long ago that work fine I didn't want to toss them, so got a box that connected them to my network. A lot cheaper and I didn't have to spend hours feeding wires through inaccessible parts of my bilge.
 

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In the case of Raymarine, I think even their newer transducers require a converter box to use them, so you wouldn't gain any simplicity by getting new ones. If you were to install a standard N2K transducer, you would need a N2K to SeatalkNG converter/cable to put in on a standard N2K network, because Raymarine refuses to use industry standard connectors.

But I didn't mean to comment on your choice and reasons - I was responding to the OP's desire to put a N2K transducer directly on his existing network. In his case, buying a new non-N2K transducer plus a converter box seems more trouble than just enlarging his thruhull to take the N2K transducer directly.

Mark
 

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In the case of Raymarine, I think even their newer transducers require a converter box to use them, so you wouldn't gain any simplicity by getting new ones. If you were to install a standard N2K transducer, you would need a N2K to SeatalkNG converter/cable to put in on a standard N2K network, because Raymarine refuses to use industry standard connectors.
If I purchase new transducers I definitely will not go with Raymarine. Either an N2K transducer or one that connects directly to my Garmin or Simrad.

As far as I can tell and according to Raymarine techs SeatalkNG is 100% N2K compatible at least in the software and communications protocols but they do use proprietary connectors which I find pointless and annoying. Sure it only takes a cable with Ray to standard connectors but still.

But I didn't mean to comment on your choice and reasons - I was responding to the OP's desire to put a N2K transducer directly on his existing network. In his case, buying a new non-N2K transducer plus a converter box seems more trouble than just enlarging his thruhull to take the N2K transducer directly.

Mark
Didn't really consider whether you were commenting specifically on my choice or the technique in general but I considered it a kludge from the getgo so not to worry, we're on the same page with that.

It was my first foray into N2K but it added a lot to the learning curve to figure how to get the Raymarine integrated into the rest. All the Garmin and Simrad stuff was 100% standard cable, plug and play. Yes my Ray stuff was previous generation but even new generation takes some messing about to connect.

Don't recall what setup the OP has for plotters but if his existing setup has a transducer connected to a plotter or he can get a cheaper transducer for an existing plotter that is N2K then that could be a cheap and easy solution.
 

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SONAR vs DEPTH

Hey,

As far as I know, if you want a SONAR display instead of just depth, you can't use a N2K transducer. The only way to get SONAR data is by connecting the transducer to the plotter / black box / etc.

If you do this, most likely the MFD will put DEPTH information onto the N2K network so the depth can be displayed by other devices. But if you want to see the bottom, or find fish or anything else like that you can only do it at the MFD.

Barry


If I purchase new transducers I definitely will not go with Raymarine. Either an N2K transducer or one that connects directly to my Garmin or Simrad.

As far as I can tell and according to Raymarine techs SeatalkNG is 100% N2K compatible at least in the software and communications protocols but they do use proprietary connectors which I find pointless and annoying. Sure it only takes a cable with Ray to standard connectors but still.



Didn't really consider whether you were commenting specifically on my choice or the technique in general but I considered it a kludge from the getgo so not to worry, we're on the same page with that.

It was my first foray into N2K but it added a lot to the learning curve to figure how to get the Raymarine integrated into the rest. All the Garmin and Simrad stuff was 100% standard cable, plug and play. Yes my Ray stuff was previous generation but even new generation takes some messing about to connect.

Don't recall what setup the OP has for plotters but if his existing setup has a transducer connected to a plotter or he can get a cheaper transducer for an existing plotter that is N2K then that could be a cheap and easy solution.
 

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Discussion Starter #34
Thanks to everyone for the info.

I ended up ordering an Airmar branded ST-800. It arrived the other day and does, indeed, have a N2K Micro connector on it ... so it should plug right in.

It _looks_ like it is the right size for the existing thru-hull ... I'll know for sure when I visit the boat this coming weekend to work on it.
 

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If it "looks" the right size, then it will fit. These transducers only came in a couple of diameters, and they are very obviously different.

Your only issue may be with a locating tab on them. When we replaced ours, the new transducer came with a small tab moulded into it which served to locate the transducer so that it faced forward. When used with its corresponding thruhull, that also had a tab recess on its top lip to match. I wanted to use our old thruhull, so I just filed a small tab recess into the top lip and everything worked fine.

Mark
 

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Still really frustrating. The only place I've found online that sells the Airmar st800 is here:
http://www.imarineusa.com/AirmarST800-INS.aspx?gclid=EAIaIQobChMIzuP39ZqK2gIViEsNCh0jKgF-EAQYAiABEgJOp_D_BwE

However, even though colemj's link claims it's an NMEA2000 device. That vendor claims it has spade connectors for Raymarine gauges. I suppose it's possible that I could just replace the end of the wire with an NMEA2000 connector and it would work?
Airmar isn't good at detailing the specifications of their products. They make the ST800 in about 10 different flavors but they are all the ST800. For sub $100 this one mentioned is definitely not an NMEA 2000 version but there are plenty of ST800 that are NMEA 2000. Here is one that is SeatalkNG (NMEA 2000) and here is one that is analog.

95% of the transducers available are 2".

Simrad and Furuno both sell the ST800 with the NMEA 2000 micro-c plug.
 

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Discussion Starter #37
Just to follow up ... I was at the boat last weekend and no only does the Airmar fit, but it's literally a drop-in replacement for the previous one size-wise.

So, despite my frustration, that worked out.
 
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