Coloured circles on map by coast?

[Tryweryn]

Newbie question alert:ambivalence:In the pic what do the colored circles by the coast mean. Cant find a reference to them on my map or googgling?

 

[Tryweryn]

Is it the angle you can see the light? But im sure i have seen them in bays where the is no lights?

 

[rich]

Light sectors, red for danger.

 

[RichardS]

It shows the safe and dangerous zones from which you can approach the light / coast. The red light areas will have shoals or rocks in that segment. Yellow (white) and green light areas are safe.

Richard

 

[Spirit of Glenans]

I'm afraid I must again harp on my usual theme about the need for training. There are plenty of evening Theory Courses where, among other things, you can learn to interpret charts. At the very least get a good sailing manual.

 

[knuterikt]

It shows the safe and dangerous zones from which you can approach the light / coast. The red light areas will have shoals or rocks in that segment. Yellow (white) and green light areas are safe.

Richard

That is I dangerous simplification.
It's true that when designing the sectors they try to put the white sector over safe water, but you can find white sectors that is partially over shoals/rocks so always check the map.
Red/Green is used to differentiate and will often mark unsafe sectors but not always - and parts of the sector can be OK to sail in.
There are lots of considerations to take when designing the light sector, so always confer with the map.


One sector tell you what sector you are in, if you have an overlapping sector from another light you know what are you are in.

Here is an example of a not so nice green sector
http://kart.gulesider.no/m/7U8ju

Here is another one, you can't go from A to B without sailing in a green sector
http://kart.gulesider.no/m/F5DAd

 

[knuterikt]

I'm afraid I must again harp on my usual theme about the need for training. There are plenty of evening Theory Courses where, among other things, you can learn to interpret charts. At the very least get a good sailing manual.

True, take classes or read book on navigation.

 

[LadyInBed]

See fig 29 in Ch 3
http://www.aztecsailing.co.uk/newaztec/theory/ch3/Chart3s3.html

Then suggest you start at Ch 1

And http://www.sailtrain.co.uk/Buoyage/leading_sectored_marks.htm

PS re googleing, try 'lighthouse sector lights'

 

[laika]

sounds like the OP might want to acquire a copy of admiralty "chart" 5011: Symbols and Abbreviations Used On Admiralty Charts:
http://www.rya.org.uk/shop/pages/product.aspx?pid=5011(RYADefaultCatalog)

In searching for a link to post I noticed that the search results threw up a (presumably copyright-breaching) pdf.

 

[RIBW]

Newbie question ......?

Dafydd,

I guess from your previous postings you are an avid acquirer of sailing knowledge!

As well as the previous suggestions, you might enjoy reading and subsequently keeping to hand "Understanding a Nautical Chart" by Paul Boissier. ISBN 978-0-470-74913-5. It was written when he was Chief Exec of the RNLI.

Also (knowing I will probably attract loads of forum flak) you could have a gander at this website which summarises why they are called 'charts'.

http://www.nauticalcharts.noaa.gov/mcd/learn_diff_map_chart.html

I hope you have a great sailing season this year
Cheers
Bob

 

[nigelmercier]

True, take classes or read book on navigation.

This is the best book I have read for a novice:
Day Skipper for Sail and Power by Alison Noice http://amzn.to/1n5KtrI

 

[Richard10002]

Notwithstanding any other dangers that might be present, if you stay in the green or white sector and head towards a light, you will eventually hit the ground the light is built on

The sectors are merely guides. If travelling through them, you should still examine the chart at its' smallest scale to see what is in, and around, your potential track/s.

 

[KellysEye]

>It shows the safe and dangerous zones from which you can approach the light / coast. The red light areas will have shoals or rocks in that segment. Yellow (white) and green light areas are safe.

I've used Admiralty and Imray charts between 1980 and 2010 and have never seen light sectors on a chart, is it new or a different type of chart? What were on the charts were the lighthouse, it's range and and type of flash.

 

[prv]

I've used Admiralty and Imray charts between 1980 and 2010 and have never seen light sectors on a chart, is it new or a different type of chart? What were on the charts were the lighthouse, it's range and and type of flash.

So how did such charts describe the sectors? The light characteristic will say something like RWR for a sector light, but no indication of which directions they cover.

Pete

 

[macd]

I've used Admiralty and Imray charts between 1980 and 2010 and have never seen light sectors on a chart, is it new or a different type of chart? What were on the charts were the lighthouse, it's range and and type of flash.

An example, as LadyInBed wrote in post #8:
See fig 29 in Ch 3
http://www.aztecsailing.co.uk/newazt.../Chart3s3.html

 

[knuterikt]

>It shows the safe and dangerous zones from which you can approach the light / coast. The red light areas will have shoals or rocks in that segment. Yellow (white) and green light areas are safe.

I've used Admiralty and Imray charts between 1980 and 2010 and have never seen light sectors on a chart, is it new or a different type of chart? What were on the charts were the lighthouse, it's range and and type of flash.

what scale charts is this?
Charts withouth sectors is not good for night sailing.

 

[KenMcCulloch]

>It shows the safe and dangerous zones from which you can approach the light / coast. The red light areas will have shoals or rocks in that segment. Yellow (white) and green light areas are safe.

I've used Admiralty and Imray charts between 1980 and 2010 and have never seen light sectors on a chart, is it new or a different type of chart? What were on the charts were the lighthouse, it's range and and type of flash.

They have always been there, just the method of showing them, with coloured arcs is fairly new.

 

[FWB]

The charts are Navionics.
Zoom in to seem here
http://webapp.navionics.com/?lang=en
mx mariner charts show the coloured sectors from St Anthony also. These are to show safe passage avoiding the Manacles.

 

[prv]

They have always been there, just the method of showing them, with coloured arcs is fairly new.

Thought so.

I remember the colours appearing on Admiralty charts not that long ago. I think they've been on Imrays (apart from KellysEye's ones apparently ) for quite a while.

Pete

 

[afterpegassus]

Dafydd,

Also (knowing I will probably attract loads of forum flak) you could have a gander at this website which summarises why they are called 'charts'.

http://www.nauticalcharts.noaa.gov/mcd/learn_diff_map_chart.html

Very generalised and not particularly accurate.

This for example : "A map is a static document which serves as a reference guide. A map is not, and can not be used to plot a course".
Ordnance Survey would be horrified to have their good work denigrated so. Hill goers would be very irresponsible unless they were able to use a map (and compass) for navigating a course .