Offshoreonly.com - Did I miss something getting nasty? (gps thread)

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- - Did I miss something getting nasty? (gps thread) (https://www.offshoreonly.com/forums/general-boating-discussion/30567-did-i-miss-something-getting-nasty-gps-thread.html)

Want to get real complicated? I once saw a fast cat with a GPS speedo, water speedo, and an airspeed indicator. He needed the airspeed to make sure he didnt blow it over when running into the wind!

Ron

These have been the best two threads. A little serious, a little yankin of peoples chains, and I think every body understands ALL the details but nobody wants it to all end :D

Do GPS's really measure in three dimensions? ;)

rjcardinal and I are brothers in GPS arms!!! Across the EARTH is what I've been trying to say!!!!!! Matters not what the medium you are traveling in is doing. And I don't boat on moving water (rivers) much, so I don't much care!!!!! LOL!!!

Re: That was an interesting and fun thread.

Quote:

Originally posted by WETTE VETTE
I posted this morning and was unable to check it unitl now and it is gone. Anyway I plan on taking my boat to a river that is flowing two or three MPH and running WOT down stream so I can have a 100 MPH boat. The best I can get is 97.8 GPS on my lake that has no current or flowing water. I was going to build my engine up to try and get to the century mark, but this way will be much easier and cheaper.:p Does anyone know of a river that flows 7 or 8 MPH? If so I will run there and maybe then I will have a 105MPH boat. Cool!!!

The Missouri flows about 7, but you don't get a mph per mph gain, I had about a 3 MPH difference between up stream and down on my GPS

WF, how was the movie, you could not keep your mind off of this thread the entire time could you?? Does your date know? we can tell her for you.

Good explanation RJ!!!

And in my case the ONLY thing I care about is how fast my boat is across the water. If we find a river that flows 20 MPH and my GPS reads 117.8 while running down stream, then my boat is still only a 97.8 MPH boat. Darn, I guess I better order that Merlin II block after all. :D

Yes, you need a Merlin II block. I actually have secret information from martian scholars that GPS is a scam! It ALWAYS reads 50mph too fast. We all need to buy new Merlin blocks, JE pistons, Merlin heads, 1271 blowers, etc. We don't even realize it but we all run slower than Bayliners but have been duped into thinking we are fast by this GPS scam. I am taking a big risk in revealing this and may soon be terminated. :D :D :D

Quote:

Originally posted by thisistank
My question is....does the current affect the gps reading??

Yes

Tank, If I shut my motors off and float in a 10 mph current, the GPS and the Radar/Laser will say I'm doing 10 mph .... I think I'm doing 0 mph ...... wasssssUp ??

Just jump out swim to shore and you will answer your own question.

My argument is a GPS cannot reliably tell you how fast your boat runs.

I think you need to take an approach more like flying an airplane, take into account the density altitude, speed of the current, actual altitude, correct for fresh water to salt water error, the induced slip up and down current (since water isn't a solid, you get some push down stream and some extra slip upstream but not 100% of the current speed) the cohesion factor of your hull.....awww hell, just lie like everyone else. :p

Ask APBA or SBI what they use to calulate speed. Speed- Distance over time. Ask Mr. Garmin how the GPS calculates speed. speed= distance over time.

mph = miles per hour. the kilo and the gps use the same calculations. the kilos use 2 opposite runs and average to help minimize one way runs.

"WETTE VETTE And in my case the ONLY thing I care about is how fast my boat is across the water. If we find a river that flows 20 MPH and my GPS reads 117.8 while running down stream, then my boat is still only a 97.8 MPH boat. Darn, I guess I better order that Merlin II block after all. "

your boat actually went 117.8. if you do the math , you would be able to verify the gps was correct.

if you were running upstream and your pitot speedo read 117.8 and your gps read 97.8, if you do the math you are traveling 97.8. it will take you longer to reach point B traveling up stream.

your pitot tells you how fast the water is moving under your boat. the gps / kilo run tells you fast fast your boat is moving over the water.

AGAIN------ ASK WHY APBA / SBI USE TIMED KILO RUNS TO ESTABLISH SPEED RECORDS. WHY DON'T THEY USE THE PTIOT SPEEDO? IT DOESN'T CALCULATED SPEED ACCROSS A SURFACE.

wette vette, you want to know how fast your boat moves accross the surface, then use gps. if you want to know how fast the water is moving underneath the boat then use a pitot speedo. do the math. the pito speedo will not give you the correct answer when you do the math.

Buster, saw the IMAX production of the International Space Station in 3D. WAY COOL!!!!!

Now, if a southboud train leaves Chicago at 4:00 a.m. and a north bound train leaves Orlando at 7:00 a.m., what does President Bush have for breakfast??

Sorry, that's the kind of question this GPS thing really is!! Speed over the EARTH!!!!!!!