How to plug in Lat/Lon into chartplotter or GPS

[Ben4195]

Hi folks, I've never needed to do this when I had my little boat, but now that I have a bigger boat I find it necessary. Specifically because I'm entering my boat into a charity race on Sandusky Bay this Saturday, and the course is published with Latitude and Longitude of the various marks. I have Garmen Blue Chart on my ipad, and I have a Garmen GPSmap 76cx, but when I enter the lat/lon I'm not getting the correct place.

For example, the starting mark is Latitude 41 degrees, 27.3' North; Longitude is 082 degrees, 44.6' West. When I plug that into the lat/lon on my devices, the point shows up in the middle of Ohio. I assume I'm doing something wrong, but I can't figure it out.

The link below takes you to the racing instructions, with a map of the course and the information on marks' lat/lon, if anyone is interested.

https://drive.google.com/file/d/0B7RnZfD7f5rZa0UxUUtXU21MYUdCVjh2ek5mLU1ScG95VU9B/view

Any help is greatly appreciated!!

 

[Ron20324]

... When I plug that into the lat/lon on my devices, the point shows up in the middle of Ohio. ...

Maybe it is a "LeMans" type of start?

 

[dlochner]

Check your GPS settings. Often there is a choice between entering waypoints as Degree/Minutes/Seconds or as Decimal Degrees.

DMS coordinates look like this: 41° 27' 18"
Decimal Degrees look like this: 41° 27.3'

and of course double check your typing.

 

[Davidasailor26]

Check your GPS settings. Often there is a choice between entering waypoints as Degree/Minutes/Seconds or as Decimal Degrees.

DMS coordinates look like this: 41° 27' 18"
Decimal Degrees look like this: 41° 27.3'

and of course double check your typing.

I think that's probably it. Your sailing instructions are in Degrees and decimal minutes. You can check your GPS to see if it accepts input in that format, or you'll need to do some conversions yourself. For example
41 degrees, 27.3 North is 41 degrees, 27 minutes, 18 seconds.

 

[Ben4195]

Dave, I think that was the trick! I had to re-set waypoint units. thanks so much!

 

[Kings Gambit]

Check your GPS settings. Often there is a choice between entering waypoints as Degree/Minutes/Seconds or as Decimal Degrees.

DMS coordinates look like this: 41° 27' 18"
Decimal Degrees look like this: 41° 27.3'

and of course double check your typing.

That would be Decimal Minutes. Twenty-seven (decimal) three minutes. Decimal Degrees would be 41.455 degrees.

 

[jssailem]

Ah shucks... I was hopping it was the LeMans race for sailboats. That would have been interesting.

Good luck in your adventure. Remember in the heat of battle that the activity is for charity.

Wonder what the organizers would do if the boat went by trailer to the coordinates in Ohio, then claimed being the first to arrive.

 

[Ben4195]

Thanks guys, and yes, John, it's very much a low-stress (just for fun) race. We did this a couple years ago and it was a blast. I think only around 10 boats participated. The protest committee is scheduled to meet to discuss any protests on the 5th Friday of July, in the basement of the Seattle Space Needle at 3:30 in the morning, or something like that.

 

[jssailem]

Good plan.. I Like it.

 

[Stu Jackson]

the 5th Friday of July, in the basement of the Seattle Space Needle at 3:30 in the morning,

Wait, that's where & when the Seahawks' cheerleaders meeting is!!!

 

[Camchain]

Ah shucks... I was hopping it was the LeMans race for sailboats. That would have been interesting.

Good luck in your adventure. Remember in the heat of battle that the activity is for charity.

Wonder what the organizers would do if the boat went by trailer to the coordinates in Ohio, then claimed being the first to arrive.

Something like this?

 

[Serenity on Hudson]

Once had a Garmin Handheld that said I was in the middle of the East River when I was standing on Land in Hunters Point. Checked everything and found that the GPS was using a different datum than the charts. Changed the datum and was back on land. This was an old GPS but who would have thought that datum's would change. Isn't a datum a fixed point?

 

[dlochner]

Once had a Garmin Handheld that said I was in the middle of the East River when I was standing on Land in Hunters Point. Checked everything and found that the GPS was using a different datum than the charts. Changed the datum and was back on land. This was an old GPS but who would have thought that datum's would change. Isn't a datum a fixed point?

Interesting question. Here's part of the answer:

Because the Earth is an imperfect ellipsoid, localised datums can give a more accurate representation of the area of coverage than WGS 84. OSGB36, for example, is a better approximation to the geoid covering the British Isles than the global WGS 84 ellipsoid.[1] However, as the benefits of a global system outweigh the greater accuracy, the global WGS 84 datum is becoming increasingly adopted.[2]

From https://en.wikipedia.org/wiki/Geodetic_datum#Horizontal_datum

 

[jssailem]

Yes @Camchain. That is a very close approximation to the thought I had. Looks like the owners and crews were having a fun time.

 

[Stu Jackson]

This was an old GPS but who would have thought that datum's would change. Isn't a datum a fixed point?

In addition to previous answers, it's also RTFM territory. And any and all navigation books cover the subject.