what's the difference!?

[bordsmnj]

how fast did you think your boat went before you ran it with a gps???
my last boat was 8mph different at WOT. solution? do not allow gps in boat. :p

[phebus]

My new boat is spot on with my GPS. I was shocked, it's the first boat I've ever had that it was right.

[JetBoatRich]

how fast did you think your boat went before you ran it with a gps???
my last boat was 8mph different at WOT. solution? do not allow gps in boat. :p
We changed the exhaust to make up for the GPS :D

[Speedin' Ian]

Last time I check ed it was right on

[jbtrailerjim]

I have yet to bring a gps in my boat. I would hate to burst my bubble on how fast my boat really goes. :cry: :wink: :D

[dicudmore]

My new boat is spot on with my GPS. I was shocked, it's the first boat I've ever had that it was right.
the speedo in my boat has been very accurate also...

[Mandelon]

My speedo is GPS, no escape for me.......

[jackpunx]

My speedo was dead nuts up to about 45mph.. After that it was with in 5mph.. But after 100mph it was a guessing game unless I had GPS.. for the most part.. I did the math with a 10-12% slip and it was usually dead on.
(per hand held GPS)
The problem is.. GPS in my experience.. Cant keep up with my boat..
I took acceleration out of the equation..
So..MY GPS said I was going faster than 100.. I would let off.. and it would stay there for a few (3) seconds before it would start to drop..
So I know when I’m accelerating.. Its generally about 3 seconds behind..
As far as your question.. The GPS didn’t rob me too much.. But I want to try a radar gun.. I hear it will give a more accurate reading.
I also think it has a lot to do with the location.. I think Parker has a shotty satalite connection.. some parts of the river are better than others.. I'll test it on havi this weekend and see if its better.
(i installed a 160 GPS speedo last weekend)

[THOR]

Mine is about 2-3 mph off at high speeds. Before I had the GPS I thought it was close, but the GPS confirmed just how close I was.

[phuggit]

My boats speedo is right on with my gps. With boats like Jackpunx, I wonder if the regular speedo is good for anything over 60mph.

[Trash]

GPS update rates are generally once per second. I would not use them for acceleration data due to the lag. Steady state measurements are very accurate. Parker satellite coverage is not a factor.
If using a radar gun, be weary of what you're aiming at. Wave fronts can increase/decrease the perceived speed. It will generally be better for acceleration tests than GPS however.

[jackpunx]

GPS update rates are generally once per second. I would not use them for acceleration data due to the lag. Steady state measurements are very accurate. Parker satellite coverage is not a factor.
If using a radar gun, be weary of what you're aiming at. Wave fronts can increase/decrease the perceived speed. It will generally be better for acceleration tests than GPS however.
thanks for the info.. So how long do I have to hold the speed to get a good reading?

[NuckinFutz]

I ran mine with a GPS last September and was happy to see the speedo was dead on throughout the range once I allowed the GPS to catch up. I was leary to see since some of my older boats were way off. I guess cheap optomistic speedos is how many cookie cutters look good. It was brought to light last summer when I loaded up several friends for a speed run and they thought all boats actually went 60. When they were actually at 60 they thought they were 80. They all went home with a different perspective on the "fast Bayliners" they owned and have been in.

[Trash]

I would say as a rule of thumb be at a steady speed for 5 seconds before taking a GPS reading. It also depends on how fast you accelerated to a particular speed. If you went like gangbusters up to a certain speed I'd wait a few seconds longer. If it was a gradual acceleration you could take a reading a little sooner.

[jackpunx]

I would say as a rule of thumb be at a steady speed for 5 seconds before taking a GPS reading. It also depends on how fast you accelerated to a particular speed. If you went like gangbusters up to a certain speed I'd wait a few seconds longer. If it was a gradual acceleration you could take a reading a little sooner.
Your right on that 5 sec rule.. Again.. I bumped up to 121 (according to GPS im sure it was faster) then I lifted.. the speedo stayed on 120 for about 5 seconds.. bummed me out.... My boat accellerates to fast and is to small to stay at those speeds unless its wed morning at a big lake with a little wind chop.. Generally it dosnt work out like that..
Oh well it is what it is..
I'll try the gradual acceleration next time.. I just start to run out of room..

[xs ultra]

Your best off with no speedo or gps,this way you can think you are going fast.I bought a gps to check the speedo and it read the same speed.max speed was 56mph.Put in about $6000 in the engine just because I wanted to get to 65mph. now I amhappy. Don't allow a gps on board it will ruin your day!

[Steamin' Rice]

The GPS slowed my last boat down by about 10 MPH at top speed.. :idea:

[LUVNLIFE]

When I GPSed the Elim Eagle the speedo was right on. It's a liquid filled Gaffrig. I don't nearly have the problem as Jackpunx has with accelerating to fast though :D :D BTW it was 73mph. :wink:

[Jetboatguru]

My little etrex stayed up with the Pro Gas flat I drove. It recorded 144 mph in the quartermile which is what the boat went through the traps at. I ran one in my Kboat at Needles and it recorded 136mph in a short burst.

[jackpunx]

My little etrex stayed up with the Pro Gas flat I drove. It recorded 144 mph in the quartermile which is what the boat went through the traps at. I ran one in my Kboat at Needles and it recorded 136mph in a short burst.
what color is it?
Have you ever tested it against the Lavorsi installed version of GPS?..
I have the yellow Garmin.. I think its the Extrex (not for sure).. it cost about $100.. It didt work any better than my intsalled version..
I was at elsionore this weekend..
I let off the gas.. and the GPS was still climbing.. :hammerhea