740s and GMR18HD not Garmin Network Compatible..

A Fishin C · Guest

Hey all, need a little help on this.

I just bought a new Garmin 740s chartplotter and GMR 18 HD and am reading that the radar is plug and play. also a note 1 that this is not "Garmin Network Compatible" also read that the radar just plugs in the back and you can split screen the radar and cp and overlay. is this true you can overlay? does one need an additional heading sensor? is "garmin network" and plugging the radar into the chartplotter two completely different things?

Any help understanding in "laymans terms" would be appreciated.

jkidd · Posted: Mon Dec 02, 2013 12:39 am Post subject:

It can do GPS, Radar and Sonar. The heading sensor would have to use NMEA 0813 or 2000. It can't connect to other devices using the Ethernet cables. On edit the overlay would work as long as you were moving if you stop then the overlay would not display correctly till you were moving again. The heading sensor would correct that.

Two Bears · Posted: Mon Dec 02, 2013 1:18 am Post subject:

By "Network" Garmin means the big system that goes through a central processing unit used on larger commercial boats. On the 740 the main head is the CPU, and you have purchased a complete package and it is truly plug and play.

I bought that package two years ago and found that I needed to play with it to see what fits me. I found the radar overlay to be wonderful for someone new to radar. You have so many options and menus to get lost in, it comes down to personal preference. I used the radar overlay mostly at first and gained an understanding what the radar image was telling me when it was overlayed on the chart. The problem I found later was that in narrow channels and & traffic the target "dot" or blip could get lost in the many colors of the chart and be missed. So, I found going to side by side or split screen with radar alone on one screen made the "targets" stand out better. But you need to play with it. For example, I have remained with the default yellow overlay color, but you might want another color. Just beat your way through the menus and try it. I went to a local lake and tested my radar on low fishing boats. I found at speed (12 kts +), even with a "wedge" under my radar (which is mounted on a low radar arch), I was not picking up a low aluminum boat dead ahead at 200 feet. But at 6 kts I did pick them up. The bottom line is that you and your equipment need to be a team and play together often enough that you know your strength and weaknesses.

Chuck

jkidd · Posted: Mon Dec 02, 2013 1:55 am Post subject:

The networking function would allow you to have multiple displays and see the radar and sonar on which ever display you choose. I have a 4210 and a 3205 and I can pick where the radar and sonar shows. Originally the 3205 was mounted on the back of the boat for fishing, but our boats are so small it was just as easy to turn and look up front. I usually set the 3205 to display a zoomed out map. If you have no plans for multiple displays it will work just fine.

kennharriet · Posted: Mon Dec 02, 2013 10:32 am Post subject:

We also have the 740s/GMR 18HD. My preference at speed is full screen radar zoomed to 3 mi. or so for detail. Most everywhere we have been is unfamiliar waters so we use the auto guidance feature often. We usually have Navionics on the IPad zoomed out for the big picture. Having AIS overlayed on the chartplotter is also great tool. We are rookies, but feel this package really increases situational awareness and reduces risk.

westward · Posted: Tue Dec 03, 2013 11:01 pm Post subject:

Is the AIS overlay mentioned a feature of the Garmin, or are you referring to a feature of your Navionics/I Pad setup ?

kennharriet · Posted: Tue Dec 03, 2013 11:53 pm Post subject:

If you have or acquire an AIS capable VHF radio, it will connect with your 740 s and display other AIS vessels on your screen. I'm sure others with more experience can vouch for the value of this tool. There were a few ocassions last summer that I altered course because of the AIS warning for vessels not yet seen visually or by radar. In one instance it was another boat departing the marina that was blind to me.

thataway · Posted: Wed Dec 04, 2013 12:19 pm Post subject:

I have been using Garmin for many years. The most recent units are the most capable. The information already given is correct. The 740x and radar are truly plug and play. When the boat is moving the overlay will be fairly accurate as long as the chartplotter is on "course" or" heading" "UP". If going very slowly, or stopped, you have to have an external accurate heading sensor. This is often a rate gyro fluxgate compass, or a GPS compass with a rate gyro compass.

Here is Garmin's word:

"When using the Radar Overlay, the chartplotter aligns radar data with chart data based on the boat heading, which is based by default on data from a magnetic heading sensor connected using a NMEA 0183 or NMEA 2000 network. If a heading sensor is not available, the boat heading is based on GPS tracking data.
GPS tracking data indicates the direction in which the boat is moving, not the direction in which the boat is pointing. If the boat is drifting backward or sideways due to a current or wind, the Radar Overlay may not perfectly align with the chart data. This situation should be avoided by using boat-heading data from an electronic compass."

The KVH fluxgate compass will give readings thru NMEA 0183. Garmin has a pricey ($830 to $900) rate gyro 3 axis electronic compass, which is NMEA 2000. (Which the 740 will run), I have also heard that the Lowrance point 1, which is a GPS/fluxgate compass combo working on NMEA 2000 backbone. If you want to do MARPA then go for the Garmin. If you want at anchor, then the Lowrance Point one or the KVH. If you are moving a fair clip--stick with the Garmin GPS overlay.

I have been using radar since the late 70's and I prefer a separate image--3 miles is good, I will go out to 16 miles every 15 minutes to look for larger fast vessels.

The AIS: just connect the radio (Like the Standard Horizon 2150) NMEA 0183 to the 740 and you will have AIS targets on your chart plotter) I have this function and love it. There is no easy way to put AIS on the Navionics chart on an I pad. You can use the App which shows AIS, but there are holes where there is no tracking and some delay, plus you have to have an active internet connection. .

T.R. Bauer · Posted: Thu Dec 05, 2013 10:08 am Post subject:

The 740s is wonderful for the money. And it is plug and play. As others noted, it doesn't network with anything else realy, but on a CD 22, I can't imagine a scenario where you are so far away you can't just look at the Garmin screen to see what is going on around you. I have found the purchase to be one of the very best I have made for my boat. There is nothing like radar in the fog.