Stupid bridge height indicators on charts

[Conachair]

.
Fabulous to see a trivial point humourously made escalate into a full scale flame war. Dyspepsia rules!

- W

There's quite often something of interest hidden away though.... Ah, so that's what the numbers in the right hand collumn of 5011 mean

And one or two on here I wouldn't feel too comfortable with onboard as navigator. Anyone completely cock sure that they are right should not be let loose with a chart and a pencil...

 

[Conachair]

Depths and drying heights are not given with a decimal always a subscript.

Though chart 5011 ed 2 gives examples ( IK 11) of "dries 1.6m" and "Dr 1.6m" for a rock which covers and uncovers.


Could chart symbol threads be the new ensigns?

I find it very common to stare at a chart and see some subtle symbols not noticed before, wonderful, fascinating things they are.

 

[Conachair]

Use electronic (vector) charts and set the units to read 'feet' that way the decimals are pretty insignificant.

Doesn't everyone do the passage plan streached out on the couch with a laptop? Rightclick/object query tells all. So much in there - http://www.iho-ohi.net/iho_pubs/standard/S-57Ed3.1/31ApAch1.pdf

 

[prv]

I find it very common to stare at a chart and see some subtle symbols not noticed before, wonderful, fascinating things they are.

I was looking at an older Imray chart the other day (early 90s) and found it interesting that the buoy symbols were different to the current Imray ones, much more amateurish. They obviously weren't drawn individually, as each was identical, but the original appeared to have been hand-drawn.

Pete

 

[SHUG]

Thanks Vics.
As is often the case , you let the dust settle and then arrive with some good factual information. The fact that it is cofusing makes me look very closely at clearing heights and the magnifying glass on the chart table has been around for decades.

 

[Elessar]

Though chart 5011 ed 2 gives examples ( IK 11) of "dries 1.6m" and "Dr 1.6m" for a rock which covers and uncovers.


Could chart symbol threads be the new ensigns?

Fair enough I could have said soundings are always in metres and you could find a fathoms chart, I should have qualified always with current UK charts.

5011 is now on ed 5 - what date is ed 2?

I find it very common to stare at a chart and see some subtle symbols not noticed before, wonderful, fascinating things they are.

totally agree

 

[Conachair]

Fair enough I could have said soundings are always in metres and you could find a fathoms chart, I should have qualified always with current UK charts.

5011 is now on ed 5 - what date is ed 2?

Ed 2 is 2001 Well there's a reason beyond guiness to go to the boat show.

Digging deeper,

From the introduction..

"Collumn 4:Other symbol or abbreviation used on admiralty charts, if different from collumn 2. The mark " " indictates that this representaion is obsolescent"

So off you go and feel smug then...

 

[Elessar]

Ed 2 is 2001 Well there's a reason beyond guiness to go to the boat show.

Digging deeper,

From the introduction..

"Collumn 4:Other symbol or abbreviation used on admiralty charts, if different from collumn 2. The mark " " indictates that this representaion is obsolescent"

So off you go and feel smug then...

Nah not smug - intrigued

I thought ed 2 would be older than 2001. Ed 4 is 2008 and ed 5 is 2011.

So what date is ed 1 and what was before it??

One of the things I love about boating is every stone you turn reveals something you don't know. When that stops I think it's time for a new hobby.

 

[Conachair]

Nah not smug - intrigued

I thought ed 2 would be older than 2001. Ed 4 is 2008 and ed 5 is 2011.

So what date is ed 1 and what was before it??

One of the things I love about boating is every stone you turn reveals something you don't know. When that stops I think it's time for a new hobby.

hang on, i'm wrong again. Ed 2 is dec 1998, record of corrections suppliment no. is 2. There's a "Published at Tauton..... 1991" on the contents page.



So who knows what the symbol for a Casuarina is then?

 

[Elessar]

hang on, i'm wrong again. Ed 2 is dec 1998, record of corrections suppliment no. is 2. There's a "Published at Tauton..... 1991" on the contents page.



So who knows what the symbol for a Casuarina is then?

but I had to look it up and haven't a scoobies what it is

 

[CelebrityScandel]

Check 5011. It is for rocks which covers and uncovers height above chart datum, symbols on the right are in decimal.

I believe we are on the same wavelength Conachair.

So for clarity and quoting USA Chart No1;

"Rock (islet) which does not
cover, height above height
datum" for these the decimal part is shown as a decimal.

"Rock which covers and
uncovers, height above chart
datum" for these the decimal part is shown as a subscript.

So the rule I suggested is that if the object (rock, bridge, etc) is against the chart's height datum then the decimal part is shown as a decimal. If the object is against the chart datum then the decimal part is shown as a subscript.

This helps clarity just from inspection as to the datum the measurement is against. As an example, this is especially useful in the case of rocks when navigating as a rock with a decimal point should be visible at all normal states of the tide whereas one with a subscript may not be.

I don't know of any exceptions to the above suggested rule, however I have never searched for any and have just found that it works in practice.

 

[CelebrityScandel]

For those that have stated that they disagree with me, most having missed the point giving irrelevant examples please read my post #51 immediately above. The quotes i give are the facts and the rule I have suggested stands up in practice.

Also, read the very interesting and constructive post by VicS.

I won't respond to Boo2 as he is still missing the point and wants an exception made for bridges. I have since taken the trouble to look back through some of his posts in other threads and my claim stands that he is inexperienced and so in no position at all to call any practice in charting "Stoopid".

 

[Elessar]

I believe we are on the same wavelength Conachair.

So for clarity and quoting USA Chart No1;

"Rock (islet) which does not
cover, height above height
datum" for these the decimal part is shown as a decimal.

"Rock which covers and
uncovers, height above chart
datum" for these the decimal part is shown as a subscript.

So the rule I suggested is that if the object (rock, bridge, etc) is against the chart's height datum then the decimal part is shown as a decimal. If the object is against the chart datum then the decimal part is shown as a subscript.

This helps clarity just from inspection as to the datum the measurement is against. As an example, this is especially useful in the case of rocks when navigating as a rock with a decimal point should be visible at all normal states of the tide whereas one with a subscript may not be.

I don't know of any exceptions to the above suggested rule, however I have never searched for any and have just found that it works in practice.

Ah - why didn't you say you were talking about American charts then you may have made slightly more sense.

This is a UK forum so assuming you are talking about UKHO charts is not unreasonable......

 

[Elessar]

I won't respond to Boo2 as he is still missing the point and wants an exception made for bridges. I have since taken the trouble to look back through some of his posts in other threads and my claim stands that he is inexperienced and so in no position at all to call any practice in charting "Stoopid".

This is an incredible statement for someone who makes statements that are plain wrong.

 

[Elessar]

Also, read the very interesting and constructive post by VicS.

on that we agree

 

[RichardS]

I won't respond to Boo2 as he is still missing the point and wants an exception made for bridges. I have since taken the trouble to look back through some of his posts in other threads and my claim stands that he is inexperienced and so in no position at all to call any practice in charting "Stoopid".

Why are you being so rude CelebrityScandel? Have you had a bad Christmas or something?

Richard

 

[CelebrityScandel]

Ah - why didn't you say you were talking about American charts then you may have made slightly more sense.

This is a UK forum so assuming you are talking about UKHO charts is not unreasonable......

I am not talking about US charts at all. You do not seem to know what USA Chart No 1 is.

It is the US document that shows the symbols described in the Regulations of the IHO for International (INT) Charts and Chart Specifications of the IHO published by the International Hydrographic Organization (IHO). I was referring to the November 2011 edition.

I doubt that you are claiming that the UKHO does not comply with the IHO requirements.

For those of a less destructive and more knowledgable mind US Chart No1 is available for download free at http://www.nauticalcharts.noaa.gov/mcd/chartno1.htm .

 

[Elessar]

I am not talking about US charts at all. You do not seem to know what USA Chart No 1 is.

It is the US document that shows the symbols described in the Regulations of the IHO for International (INT) Charts and Chart Specifications of the IHO published by the International Hydrographic Organization (IHO). I was referring to the November 2011 edition.

I doubt that you are claiming that the UKHO does not comply with the IHO requirements.

For those of a less destructive and more knowledgable mind US Chart No1 is available for download free at http://www.nauticalcharts.noaa.gov/mcd/chartno1.htm .

Find me a decimal depth on a current UK chart. I dont know of one. If you do I bow to your superior knowledge on depth notation.

You were still wrong about brackets ( displaced depths) and height datum. Boo2 who you chose to belittle, which I have to say rather irritated me, has not said anything that is factually wrong despite what you called a lack of experience.

 

[CelebrityScandel]

Find me a decimal depth on a current UK chart. I dont know of one. If you do I bow to your superior knowledge on depth notation.

You are still missing the point. I have said that against the HEIGHT DATUM the figure is given as a decimal, it is those which Boo2 was asking about with reference to bridges.

It may or may not be that UKHO charts never show the decimal part for depths as a subscript (against the CHART DATUM) and I am several thousand miles away from the boat at the moment and so cannot check (EDIT: ViS's post showing charts for Southampton certainly show decimal depths and those being to the Chart Datum not the Height Datum are printed as subscripts as I have previously stated - I ssume they are UKHO charts). But they sure do for heights against the chart's Height Datum, unless of course, Boo2 and others that have mentioned them is mistaken in his claim that bridges do.

You do not seem to understand that charting is to international conventions and those countries recognised as having official hydrographers all work to those. You also do not seem to realise that these organisations share charts and the world is divided into responsibility regions for them. You also do not seem to realise that many of us sail internationally (our big boat is on the move most of the time) and do not find the differences in charts from those providers that you seem to imagine there are.

 

[SHUG]

Quote from Celebrity Scandal post #14
"But others have seen the point of my original suggestion so I have no more to say on the matter."
Do you wish to retract that statement?????