GPS Speedometers
 

Can a GPS speedometer be hooked up to an exsiting GPS unit or do you have to buy the seperate GPS sensor?
A Gaffrig GPS speedo cost about $200 and the sensor cost about the same. Is it really worth $400 for a speedometer?
What do y'all think?

Or you could go with a Nordskog and knock off about a hun. ;)

Here is a link to a thread on this subject.

GPS Speedos

Good luck.

I hooked mine up to my garmin unit and it works fine, You would hook the wire from the sppedo to the "NEMA" output on the GPS. Also both ground for the GPS receiver and the spedo head should be the same too. Some gps's have different settings for this output wire for other equipment, You may have to go in the setup screens to choose NEMA. but I believe the NEMA standard is 4800bps and that is what the GPS speedo use's for data.

I had mine hooked up this way first then I changed back to the full time receiver. My problem was I had to turn on the switch to the Garmin unit and the hold the on button first before it would start to accuire and show MPH. I had bought the whole kit and had the second reciever anyhow.

Garmin has OEM Sensors and the GPS35 is what Gaffrig Perf uses: http://www.garmin.com/oem/

Here is the instruction sheet: http://www.garmin.com/manuals/spec35.pdf

I think I bough one a year ago for a motorhome for about $135.00 from a wholesailer. You could also use the GPS36, it is the same but on a pole and white for marine.

You would use the Black, Red and white wires only. White would go the the GPS Input.

Here is a pict: my existing Garmin gps reciever is on the pole abover the walk way, the "new" one (Garmin from gaffrig) for the speedo I mounted just abouve the trim indicators. They only came in black so I had painted it to match with automotive paint, I just drilled one hole and used sticky tape to hopld it down for now to verify that it worked there. It seems to be fine, If the tape goes bad I will just calk it down.

Be carefull painting GPS antennas, especially white. Most paints these days have metal in them, titanium oxide in whites, which can kill the antenna reception. Be sure to paint a test piece of plastic first and place it over the antenna to be sure it doesn't obstruct the signal.

-Greg

I have to ask this, it has been driving me crazy! Why buy a GPS speedometer??? These things cost $400 to $500 and all they do is read out the speed. For the same money or less you can buy a GPS unit from Garmin, Magillian, etc that not only will give you speed but also give you max speed, avg speed trip miles and navigation info. For just a few dollars more you get charts. Am I missing something here?

Yes they will do all that but I had mine mounted down lower and It was hard to read. Where the center guage is it is less destraction from the view ahead. Some of the GPS's you can move the data fields arround and make the numbers bigger.

As for at the paint I used Duplicolor arctic white, it seems to work fine.

I agree, a "speed only" unit is somewhat of a waste. I have a full mapping GPS with depth on the Nav panel, and run a remote display head to the drivers panel for the speed readout. Cost for the remote head was only $100, and now I don't keep tearing up speedo pitots all the time. I do however miss the "extra speed" of the water speedo :) .

-Greg

I already had a gps hand held. I wanted to get the gps speedo because it would be easier to read. I hooked the speedo up to the unit using a patch cable, but finding a cable with both signal output AND power was extreamly difficult. In retrospect it's not worth the trouble and I should have just spent the money for the antenna.

GPS speedos don't really cost much more (if any) than a high quality conventional speedo. If you buy a liquid Gaffrig it will cost at the very least something over $200.00 just for the head. Add another 200 (of more) for a spring loaded pitot and hose and you could have bought a GPS unit for about the same money. Of course you can spend less but you won't get the same quality or accuracy either. My next speedo will be a GPS because I want to get rid of the pitot and I like the ability to read slow speeds which is lacking on the 100 MPH and up conventionals.

Oh, and don't forget the aesthetics of having a matching gauge in the middle of your dash versus a GPS unit stuck up there somewhere . . .

GPS Speedo
 

Thanks guys. This info helps out a lot.
Raypanic, I appreciate you going the extra mile with your detailed instructions, links and pics. It must be a Powerquest owner thing!!!!!!

Padraig,
I agree with your statement. I have a Garmin GPS already mounted in my boat. The only reason I would want a GPS speedo is to advoid having the plugging problems with the standard speedometer. Down here in South Louisiana, we are not known for having the cleanest waterways. Lots of duck weed and such is always giving us problems plugging up the pickups for standard speedometers. Since owning this boat, my speedometer has been plugged more than working.
I guess that is the price you have to pay to live in Paradise!:D

Why I did a DIGITAL gps
 

01.Original pkup was in the ft. I went with the IMCO Extreme SC and it does have a speedo hookup(2" shortie).
02.Since I didn't have holes in the transom for a pkup.
03.Since I did have a hole&stock speedo in the dash that didn't work.
04.All of my gauges have the HTM logo on them so a anolog still would not match perfectly to my gauges.
05.Nord. digital GPS is what I went with. I like the looks of the digital. You have an exact speed reading down to the nearest tenth.
06.U can find the perfect trim setting of any speed with the digital one. Not so easy if not impossible w/analog.
07.Digital reads from about 3 to 200mph. If you get a high end analog then you don't have the low end readings. EX:Like from 25 mph or 30 on up.
08.Digital will read (one at a time) mph, knots(big deal),compass, rpm,&volts.
09.Run out of room on that dash, know where to put your boost gauge for your new blower motor. No problem,sh*t can the stock volt meter and put the boost gauge in it's place.

Mike, I think you misunderstood my question. :) It wasn't analog vs digital, it was why have a GPS speedometer at all. For the same price as a GPS speedo you could have a good GPS with its own large number digital read out and more features. You could have kept the voltmeter and **** canned the speedometer and put a boost guage in its place. ;)

I understood your question
 

:D just thought I would give some of the good with a stock looking speedo and not a dash mount.
One hell of a boost gauge in the speedo hole :eek:
My wish would have been to do away with the tach and speed and put in a decent size GPS

Good looking dash!

I know what you mean about wishing you had room to mount a good size GPS. I mounted my 182 using a RAM Mount. Mounted off to the right side, it looks ok but flush mount would of looked better.

recent gps thread
 

here is a link to a recent gps/speedo thread

http://www.offshoreonly.com/forum/sh...ghlight=garmin

My Speedo never worked right! It was about 10 mph slow. I removed the pitot tube and assembly filled the holes and don't half to worry about it. My dash is the same as Ray's I mounted the antenna under the dash and it WORKS great:cool:
I also bought a matching rocker switch to replace one on my dash that I no longer needed (looks clean). Thats why I decided to use a GPS speedo.
Scott

My speedo reads about 3-5 mph higher than GPS. So, I am keeping it! :D I have my GPS in my corner of the boat to read. My speedo is out in the open for all the passengers to read while we are doing 80+ mph (according to the speedo) I'm the only one that needs to see "real" speeds! :D

Reason's I switched to GPS speedo.
1) My pitot tube was bent severely and the only "good" one I know of costs over $200:eek: It will last but the tube still gets plugged.
2) I have my gps mounted on a RAM mount, but I want to use it as a GPS, not a speedometer. You cannot do both and drive the boat.

All my gauges must be easy to read and easy to find. All I want to have to do is glance at the gages and know what they are supposed to be reading. The less I have to look at the gauges, the more I can pay attention to the important things, like the water in front of me.