Depth indication close to shore

[Jim Cate]

Alla youse guys who were waffling about upthread should read Alan's post just above and really pay attention! A very good post on the subject!

Jim

[RaymondR]

Originally Posted by Jim Cate

Alla youse guys who were waffling about upthread should read Alan's post just above and really pay attention! A very good post on the subject!

Jim

Yep, it is a good post but I haven't bought a paper chart in about fifteen years and whilst I was aware of the ZOC have found that even in fairly modern charts there's still a good bit of imagination in the representation of shoal, near shore areas, particularly in areas away from commercial ports, and that oft times Google Earth can give a better representation of what one is likely to find in the sorts of places us recreational seafarers often frequent.

[goboatingnow]

Originally Posted by Jim Cate

Alla youse guys who were waffling about upthread should read Alan's post just above and really pay attention! A very good post on the subject!

Jim

Nope it’s not a good post , cause that information is non existent in recreational charts both electronic or otherwise. It’s only slowly becoming available on IMO compliant ECDIS

Furthermore typical recreational areas will never have improved ZOCs and the vast majority have traditional Source Diagrams and that’s unlikely to change.

Maybe in 20 years it will be a good post

[Cadence]

My father would say read the water. That meant look at the surface. Not a thing that can be taught other than experience.

[Montanan]

So as to be sure there is no confusion and to provide clarity, the shallowest point near shore is a shore.



As to "depth indications close to shore", I have found that my keel is exceptionally reliable as to discerning and notifying of such shallows. It has never failed to provide guidance as to skinny water conditions. My keel being much more accurate than any chart I have ever viewed and it is not tide dependent, rather providing real time data.

[Wotname]

Originally Posted by Montanan

So as to be sure there is no confusion and to provide clarity, the shallowest point near shore is a shore.



As to "depth indications close to shore", I have found that my keel is exceptionally reliable as to discerning and notifying of such shallows. It has never failed to provide guidance as to skinny water conditions. My keel being much more accurate than any chart I have ever viewed and it is not tide dependent, rather providing real time data.

I'm not so sure.....

I have found my lifting keel gives me quite variable data unlike more surefire traditional methods like jumping over the side or for wusses, the lead line.

[glenn.225]

I have not seen it posted here but I take clues on bottom shape from the land around the shore. That is to say if the land is smooth and evenly sloped then I would expect the bottom to be similar. If the land is very uneven, cliffs and rocks I would expect that on the bottom and be very careful. All charts will have some inconsistencies in depth and are not infallible.

[Alan Mighty]

Originally Posted by goboatingnow

Nope it’s not a good post , cause that information is non existent in recreational charts both electronic or otherwise. It’s only slowly becoming available on IMO compliant ECDIS

Furthermore typical recreational areas will never have improved ZOCs and the vast majority have traditional Source Diagrams and that’s unlikely to change.

Maybe in 20 years it will be a good post

For sure, the availability of CATZOC charts, ones adhering to the ZOC system, depends on the jurisdiction(s) in which you sail.

Starting around 2014, all new Australia large scale charts are CATZOC. Electronic and paper nav charts. Small scale PNCs are not all CATZOC.

Australia is not the richest economy on the planet - it usually stands anywhere between No. 13 and No. 20 in rank order by the size of the economy. If Aus can afford to move to CATZOC, there are a few other economies that have the capacity to move to CATZOC.

I cannot speak for the entire set of UKHO charts - one of the largest coverages in the world - but I believe some large proportion of paper and electronic nav charts are now CATZOC.

UKHO has a better version of an explanation of ZOC than what I wrote, at: https://www.admiralty.co.uk/Admiralt...OC%20Table.pdf

Australians all can download the Mariner's handbook for Aus waters, with much the same explanation of CATZOC, for free. See: https://www.hydro.gov.au/prodserv/pu..._Edition_5.pdf

Of course in Aus, chartlets made with planing hull runabouts in mind such as the QLD Beacon to Beacon series of charts for recreational boaters are not yet CATZOC. The taxpayers who pay for the hydrography and cartography will soon or late demand that that those charts are certified to ZOC standards.

I've not sailed in US water for 2 decades. My understanding is that NOAA started introducing ZOC for selected charts in about 5 years ago, 2016. So YMMV.

One message is to regard all non-CATZOC charts as ZOC C or ZOC D (or worse) and to follow the recommended UKC allowance for those charts.

ENC and PNC are just like other goods you buy. Even in Third World economies, packaged food comes with nutritional info that is certified; in developed economies urban residential houses are built to standards; and even generic pharmaceuticals made in India or China are tested, approved, and certified.

[requiem]

Originally Posted by Alan Mighty

I've not sailed in US water for 2 decades. My understanding is that NOAA started introducing ZOC for selected charts in about 5 years ago, 2016. So YMMV.

Both OpenCPN and SEAiq can overlay the ZOC symbols, the data for which is generally present on the ENC charts I use with them. (Hard to stick a source diagram on those charts.)

It certainly doesn't help that many recreational apps and plotters are the nautical equivalent of an Easy-Bake oven. At least with paper both professional and amateur navigators would be expected to have the same skillset and use similar tools.