chart question about symbols

[03silvers]

Downloaded the navionics app for iphone. 10bucks why not. My question is what are the small "9" and "8" after the depth numbers on the chart? What is the SY as well?

 

[UncleWillie]

Re: chart question about symbols

10.8, 7.9, etc.

Sy = Sticky Bottom

 

[dingbat]

Re: chart question about symbols

Most charts will display additional info if you put the curser on the point.

 

[Pez Vela]

Re: chart question about symbols

If the depth is displayed in fathoms, the first number will be fathoms, and the second subscript number will be feet (never exceeding 5). If the depth is displayed in feet, there is only one number. If the depth is displayed in meters, the first number will be meters, and the second subscript number will be in tenths (ranging up to 9). So it appears to me that you have set the depth units on your iPhone to display the depth in meters. You may use the menu function to change this to display the depth in whatever units you prefer.

 

[Don S]

Re: chart question about symbols

Goto this link, http://www.nauticalcharts.noaa.gov/mcd/chartno1.htm and download chart #1. It covers ALL the symbols, and abbreviation used on charts.

 

[superbenk]

Re: chart question about symbols

If the depth is displayed in fathoms, the first number will be fathoms, and the second subscript number will be feet (never exceeding 5). If the depth is displayed in feet, there is only one number. If the depth is displayed in meters, the first number will be meters, and the second subscript number will be in tenths (ranging up to 9). So it appears to me that you have set the depth units on your iPhone to display the depth in meters. You may use the menu function to change this to display the depth in whatever units you prefer.

I'm not sure that's correct or Navionics is doing things in a non-standard way. I have the same subscript numbers and my settings are for depth in feet (just checked). Also, where I have the subscript numbers are on the edge of the dredged channel. The center of the channel reads "34FT" and then at the edge it says 18 with a subscript 7 or similar. I know the channel is 34' there because of my depth finder. I'd post another pic but I'm on my iPhone.

Also, for your fathoms thought, shouldn't it be subscripts up to '6' since a fathom is 6'?

Anyhow, I still have the same question and something doesn't add up.

 

[Pez Vela]

Re: chart question about symbols

Well, I thought I remembered the answer from my "sea school" days, and I checked it out on my (older) version of Navionics which resides on my iPhone. That seemed to check out with my answers above. However, this is what the definitions say on NOAA's CHART No. 1:

"Soundings - The sounding datum reference is stated in the chart title. Soundings on NOAA and NGA charts may be shown in fathoms, feet, fathoms and feet, fathoms and fractions, or meters and decimeters. In all cases the unit of depth used is shown in the chart title and outside the border of the chart in bold type. (See item Ab in Section A.)"

So Navionics, which did you choose when it comes to fathoms? By the way, where the datum is in fathoms and feet, you can not have 6 (or more) feet because that would bump you up to another fathom.

 

[superbenk]

Re: chart question about symbols

Oh ya, 5 does make sense

Still not sure how the markings add up but that's good info, thanks!