gps speedometers

jim_m5

Member
Aug 19, 2008
275
Woodstock, GA
Boat Info
340 Sundancer 2000
Engines
7.4L 310hp V-Drives
Does anyone have a recommendation to replace the dashboard speedometer gauge with a GPS speedometer in my style boat? I mean pull it out and put in the same size but one that uses GPS.

Any product direction?
Is it difficult to install?
Are they expensive?
Would it blend into the dash nice or stick out like a sore thumb?
 
I have a Nordskog GPS speedometer on mine. I love it - it is very accurate and looks cool. Especially at night. I think it is a few hundred bucks - mine came installed when I purchased the boat used.
 

Attachments

  • IMGP0207.JPG
    IMGP0207.JPG
    69.8 KB · Views: 264
Thought it better to revive this short old thread rather than start new. @Henry Boyd

Can you explain how to do the above? My ‘05 240SD has a SC speedo (70mph without lcd, lcd is located on tach) with a 3 wire plug from oem harness (blue, yellow, & red wires). I have a Garmin with NEMA 0183 output.

Everything I’ve found online seems related to the speedo with lcd and more wires. I’m hoping since my speedo is designed to work off a digital signal that this should still be possible.
 
Thought it better to revive this short old thread rather than start new. @Henry Boyd

Can you explain how to do the above? My ‘05 240SD has a SC speedo (70mph without lcd, lcd is located on tach) with a 3 wire plug from oem harness (blue, yellow, & red wires). I have a Garmin with NEMA 0183 output.

Everything I’ve found online seems related to the speedo with lcd and more wires. I’m hoping since my speedo is designed to work off a digital signal that this should still be possible.

Does your tach also have buttons? If yes, then that would be the receiving device. From the Garmin you only use the wire pair that exports data - one wire is data +, the other is - SC ground. 2005 vintage Smartcraft only accepts incoming nmea data, so you will be looking on the tach harness for a long two wire pigtail with a blue wire and a white wire. The blue is connected to the Garmin nmea ground and the white is connected to the Garmin data out +. Send me your email address via PM and I’ll forward you a copy of the Smartcraft manual that covers this as well as the calibration set up info.
 
Thanks for replying.

Yes Tach has buttons. Blue SC cable goes to tach. Actually on the last few inches before the plug it goes into a plastic cover (like automotive split loom without the split) with a sticker about a terminal resistor. Coming back out of that plastic over-cover are a 3 wire plug that goes to the 4 function center gauge and 2 wires to the alarm buzzer. I don’t see any other pigtails.

So are you telling me that I should cut open the blue SC cable to find a blue wire and a white wire inside that I need to connect to the Garmin’s NMEA output wires?

I’ll PM you my email. Perhaps seeing a diagram will clear it up for me.

Thanks again. This would be a great solution.
 
Thanks for replying.

Yes Tach has buttons. Blue SC cable goes to tach. Actually on the last few inches before the plug it goes into a plastic cover (like automotive split loom without the split) with a sticker about a terminal resistor. Coming back out of that plastic over-cover are a 3 wire plug that goes to the 4 function center gauge and 2 wires to the alarm buzzer. I don’t see any other pigtails.

So are you telling me that I should cut open the blue SC cable to find a blue wire and a white wire inside that I need to connect to the Garmin’s NMEA output wires?

I’ll PM you my email. Perhaps seeing a diagram will clear it up for me.

Thanks again. This would be a great solution.

no do not cut any wires. I’m sending the pdf. Take a look at that and it will explain things.
 
Ok I went through the document I sent you. It appears you need to either have a System Speedo, or a vessel view type display to have gps speed output. More correctly, you need a System Speedo, or vessel view device to “translate” the data.

There are two types of Smartcraft gauges, System and Link. The System gauges parse data from the network, process it, and then dole it out to the link gauges. The Link gauge is just a display. Your current speedo is a link version. You can get gps data to the Speedo, but you need to add some hardware.
 
So no chance of sending data to System tach and then having it passed down to the Link speedo? I’m guessing that’s how the speedo is getting it’s data now it’s just that the tach isn’t getting gps speed to pass.

If you could, let me know what hardware I would need.

Thanks
 
Once you review the pdf it will become clearer. I’m guessing you would need a system Speedo gauge, 4 port junction box, one dust cover, a system tach harness, and a system Speedo harness. Your existing blue trunk cable goes into the junction as does the two gauge harnesses. The dust cover (without resistor) closes off the unused port. Normally there would be a termination resistor on the junction box. But in you case there is a termination resistor built 8th the helm end of the blue trunk cable.
 
Thanks ZZ13. I just read your post and will re-read.

Henry, so my current SC would go to junction (essentially a splitter) then 2 ports of the junction connect via new short SC cables to the tach and new system speedo?

Am I correct in assuming that a system speedo would have an lcd screen also and I’d be able to display one mode on tach screen and another mode on speedo screen?

Appreciate you reviewing my interpretation.

Seems like a bunch of effort to get my speedo to work when I already have speed shown on Garmin. Just hate a nonfunctional gauge. Wish I could buy a self contained gps gauge and put guts in the Sea Ray gauge using existing matching face and needle. Or just pull needle and print something like a SR logo to put over gauge face to make a dummy gauge.
 
Thanks ZZ13. I just read your post and will re-read.

Henry, so my current SC would go to junction (essentially a splitter) then 2 ports of the junction connect via new short SC cables to the tach and new system speedo?

Am I correct in assuming that a system speedo would have an lcd screen also and I’d be able to display one mode on tach screen and another mode on speedo screen?

Appreciate you reviewing my interpretation.

Seems like a bunch of effort to get my speedo to work when I already have speed shown on Garmin. Just hate a nonfunctional gauge. Wish I could buy a self contained gps gauge and put guts in the Sea Ray gauge using existing matching face and needle. Or just pull needle and print something like a SR logo to put over gauge face to make a dummy gauge.

I don’t know how many of the lcd screens overlap between the tach and speedo. I used a link tach and Speedo controlled by a System View SC5000 display. With that the gps feed gave a trip computer like function where it recorded the fuel consumed. By only resetting the trip computer at fill ups, the fuel consumption to date was far more accurate than the fuel gauge.

To be honest, your last comment is right on the money. The only analog gauges we have on the current boat are two Volvo Tachs, the rest of the engine monitoring is via the Garmin and Raymarine mfd displays.
 
Thanks. Too bad Sea Ray or VDO or Mercruiser doesn’t make a retrofit plug n play gps speedo. I bet it would sell.
 

Forum statistics

Threads
112,942
Messages
1,422,699
Members
60,927
Latest member
Jaguar65
Back
Top