Nautical chart symbols

[kombiguy]

I have been looking around and I can't seem to find out one particular answer. On the nautical charts I have seen there are a number of lines. Lat/long lines are easy. The ones that I don't know are the ones that run diagonally across the charts in both directions creating a sort of diamond pattern. Can anyone here enlighten me as to what they represent? Thanks in advance!

 

[JKPAO]

Loran X and Y
See you topside! John

 

[BluewaterSail]

With the old Loran sets, you needed to find the location on the chart based on the 2 coordinates that JKPAO mentioned. With GPS, which is much more common today for alot of reasons, you get the lat and long directly, even in the simplest sets. So those types of lines that you see would not be relevant to any navigation you would do today, unless you have an interest in history. The first civilian GPSs were already beyond that. (not that Loran C lines would have anything to do with the GPS lower level calculations.)

 

[kombiguy]

Thank you! I can now obsess over something else! Do they still use loran much? I thought that had disappeared.

 

[BluewaterSail]

No, they don't. It is nowhere near as accurate as GPS. The signals bent and got distorted. And didn't have worldwide coverage even in its heyday.

 

[kombiguy]

Thanks! This place is a font of information.

 

[BluewaterSail]

Charts that have little military value don't get updated very often. Thats probably why you have seen those lines that no one cares about these days. I remember when I bought a stack of charts in 1992 for the first leg of my planned sailboat circumnavigation, the notes on one chart which was the details of some little Pacific Island, indicated that it was based on a survey done by Captain Cook. And it looked like a pencil sketch!

 

[DennisS]

the notes on one chart which was the details of some little Pacific Island, indicated that it was based on a survey done by Captain Cook. And it looked like a pencil sketch!

Little known Factoid

James Whistler (of Whistlers Mother fame) worked for Coast & Geodetic Survey, forerunner of NOAA. He did the sketch of Anacapa Island, he was fired for putting the seagulls in the sketch.

Today's Document from the National Archives

They still have the copper etching of the sketch

 

[BluewaterSail]

Little known Factoid

James Whistler (of Whistlers Mother fame) worked for Coast & Geodetic Survey, forerunner of NOAA. He did the sketch of Anacapa Island, he was fired for putting the seagulls in the sketch.

Today's Document from the National Archives

They still have the copper etching of the sketch

Too bad that they will eventually phase out those beautiful sketches.
The government firing James Whistler is like the high school algebra teacher that flunked Albert Einstein.

 

[OBXDIVEGUY]

For details about all the different doohickies on a nautical chart, refer to a book called Chart #1 by NOAA. It is the legend for all the symbols and stuff.