GPS for speedo ?

(rynron1722) · (rynron1722) **Join Date: Feb 2005** 07-11-2005, 11:05 AM

The paddle wheel on my boat has broken and gives inconsistent fluctuating speed. Does anyone use the handheld GPS for a speedo, I personally have never seen or used one. I was wondering how well it worked and if it had any problems. Also recommendations would be helpfull.

Thanks

(jklein) · (jklein) **Join Date: May 2001** 07-11-2005, 3:38 PM

I just used one to calibrate my speedo's. Worked pretty well.

(magic) · (magic) **Join Date: Mar 2002** 07-11-2005, 4:08 PM

I think that you would run into some quricky issues if using GPS in a moving river. I'd guess that it would show your actual speed (boat + river flow) and not relative speed.

On a open body of water, I don't see why not for GPS. I use one to calibrate my speedo like John does too.

(rodmcinnis) · (rodmcinnis) **Join Date: Sep 2002** 07-11-2005, 4:52 PM

I would expect that the update rate on a GPS speed indication would be too slow to give a decent pull for wakeboarding.

What is broken about the paddle wheel?
What is the speedo (Perfect Pass or other)?

If it is a Perfect Pass system then I believe that the little paddle wheel is easily replaced.

(wake_upppp) · (wake_upppp) **Join Date: Nov 2003** 07-11-2005, 6:13 PM

We use a GPS for speedo and run PP in the tach. mode. It works in real time, instantly showing changes. It will be coming in new boats if not allready available.

(cyclonecj) · (cyclonecj) **Join Date: Jul 2001** 07-11-2005, 7:03 PM

You can get an in dash GPS speedo from this place, there's one specifically for ski boats

http://www.livorsi.com/catalog/gps.htm#GPS

walt 07-11-2005, 7:17 PM

I use a GPS sometimes too and it works great.

It would be more accurate on a river or moving water than a Speedo

(dbjts) · (dbjts) **Join Date: Nov 2003** 07-11-2005, 11:35 PM

We use GPS on the river and have no problems with accuracy or update time.
You always need to factor in the flow of the river usually 2-3 MPH and add or subtract that from your desired speed, depending which way you're going.

(wakehound) · (wakehound) **Join Date: Oct 2003** 07-12-2005, 8:29 AM

Walt- But we want the speed of the boat going over the water, not the "real" land speed.

robertt 07-12-2005, 2:49 PM

I am with Mark on this one. If you like to ride at 20mph, and you are on a river with a 5 mph current, going upstream your speed in relation to the only thing that matters (the water) is 25mph. 15 going the other way. That's a huge deal to anybody.

As with all physics problems, it sometimes helps to take it to an extreem....if the water was going 200 mph downstream, for you to see 20mph on your GPS going upstream you would need a boat and rider capable of doing 220mph for an extended period of time.

I cant do that :-)

walt 07-12-2005, 3:01 PM

Robert, That makes sense.

(cdm) · (cdm) **Join Date: Aug 2003** 07-12-2005, 4:31 PM

am i missing something here? a gps will indicate your speed. this speed will be the same on land and on water. the flow of water will not effect the gps. if your traveling 200 mph up stream your traveling 200 mph. if your traveling 200 mph downstream, your doing 200.... however, when calib. your speedos on a flowing river via a gps, the flow could cause a mis calib. we agree?

(wiltok) · (wiltok) **Join Date: Feb 2003** 07-12-2005, 5:06 PM

Let's say you are on a boat and the current is flowing 20 mph. You are facing into the current, in gear and "moving" relative to the water at 20 mph. On land, looking at the boat, it will be standing still. Since a GPS uses the same concept - the GPS speedo will read zero. The boat speedo however will read 20 mph.

robertt 07-12-2005, 5:59 PM

Tell ya what. Lets test this. I will bet you one million dollars that my 20mph is faster than your 20mph when I am driving downstream.

Here is the test. Any boat, with perfect pass. You and me, one case of beer and a GPS, on any river that is moving over 4mph.

We set the perfect pass at 20mph, and you drive upstream and we time how long it takes to drive 2 miles. Then we turn around, and I drive downstream. Same 20mph speed, and we will see if it takes less time for me to drive the exact same distance on the GPS using the exact same perfect pass setting.

One million dollars....anybody up for it :-)

OK, not a mill...you name the bet.

(cdm) · (cdm) **Join Date: Aug 2003** 07-12-2005, 6:46 PM

so we all agree.

(retrofridge) · (retrofridge) **Join Date: May 2005** 07-13-2005, 7:07 PM

I am running a Garmin Street Pilot 3 couldnt be happier.

(retrofridge) · (retrofridge) **Join Date: May 2005** 07-14-2005, 6:36 AM

Heres a pic

gps

(mississippireb)

I use an Garmin Etrex Legend with an automotive mount. I have it tucked right down beside the dash. It is a heck of a lot more accurate than my pitot speedometer.

Daniel

(rynron1722) · (rynron1722) **Join Date: Feb 2005** 07-14-2005, 10:27 AM

Daniel does the garmin update quickly just like a regular speedo. BTW I live on smith lake, right around the corner from duncan bridge.

(wake_upppp) · (wake_upppp) **Join Date: Nov 2003** 07-14-2005, 6:15 PM

From above post:
"It works in real time, instantly showing changes."

(socalwakepunk) · (socalwakepunk) **Join Date: Dec 2002** 07-14-2005, 7:17 PM

Malibu has already done GPS, seen it factory on a 2001 Wakesetter. Yes, moving water (river) will cause speed to read either fast or slow.

jayazz 07-15-2005, 5:35 AM

I have been using a garmin etrex handheld for the past year, i have it mounted to the dash, and plugged into the cigar lighter, it works a treat, i think its much better than the speedo

(jdaviso1) · (jdaviso1) **Join Date: Jul 2004** 07-17-2005, 10:23 PM

I use a Garmin GPSMap 60C mounted on the dash. Works great (except while at the river). Having a moving map is handy when in unfamiliar waters.

http://www.garmin.com/products/gpsmap60c/

~J.