[Public-List] Charts and depth sounding

Sat Feb 19 04:29:11 PST 2022

I don't think that is completely accurate Gordon. I don't know exactly 
what triggers issuance of new charts, but it is not a survey of the 
entire area covered by that chart.
I was on a boat that received automatic corrections and editions of 
charts in our library (I think there were 113), oddly enough, a service 
provided by a company more or less in my hometown (Easton, MD.).
  Mouth of Chesapeake Bay was especially susceptible to new additions. It 
was also being continuously corrected. My theory is that was because of 
the large presence of USCG-the training facilities at Yorktown and the 
large base at Portsmouth. I think what happens is; these guys go on a 
cruise, they notice a marker they believe is out of position, that 
generates a correction. Then, a couple weeks later, another team goes 
out, notices the marker just corrected is not in the corrected spot, 
which generates another correction. Eventually the stickers pile up so 
thick on the chart it no longer folds. That is when you get a new 
addition. It was the Mate's job to do the cut and paste on all the 
charts, he was quite busy at times, especially if it was a month or two 
getting to our supply bin. It was always nice to get a new addition, old 
charts make great crab paper.
Surveys are sometimes included in the corrections, but they are always 
the dredged shipping channels.
Michael Grosh
#220
Also formerly of Tug Oyster Creek

------ Original Message ------
From: "Gordon Laco via Public-List" <public-list at lists.alberg30.org>
To: "R Kirk" <isobar at verizon.net>
Cc: "Gordon Laco" <mainstay at csolve.net>; 
"public-list at lists.alberg30.org" <public-list at lists.alberg30.org>; 
"public-list at alberg30.org" <public-list at alberg30.org>; 
"a30240 at earthlink.net" <a30240 at earthlink.net>
Sent: 2/18/2022 10:20:14 PM
Subject: Re: [Public-List] Charts and depth sounding

>Hello - I reckon the CHS would offer a different view on that.   New charts are new charts resulting from fresh survey and soundings…
>
>
>Gordon Laco
>www.gordonlaco.com
>
>
>
>
>
>>  On Feb 18, 2022, at 10:06 PM, R Kirk <isobar at verizon.net> wrote:
>>
>>  Don't count on fresh surveys.
>>
>>  The USA is similar with frequent chart updates. But the very frequent Weekly Notice to Mariners*   invariably just shows buoy shuffling. Even the chart reissues which are done after several years are merely reprints to replace the previous heavily pen & inked corrected versions before they become illegible. In no cases are the soundings changed from the last century's work - unless you're lucky. The few NOAA survey ships which are left service the Navy & commercial shipping interests. Local surveys that interest we sailors are contracted out, as budget permits. I'm guessing Canada is similar.
>>
>>  *My earliest recollections were of my father getting the weekly notices in the mail. He called it the "Boat sunk notice" because it reported the location of ships sunk by German subs off the south shore of Long Island early WW2.
>>
>>
>>  -----Original Message-----
>>  From: Gordon Laco via Public-List <public-list at lists.alberg30.org>
>>  To: Alberg 30 Public List -- open to all <public-list at lists.alberg30.org>
>>  Cc: Gordon Laco <mainstay at csolve.net>; a30240 at earthlink.net; A30 Public List <public-list at alberg30.org>
>>  Sent: Fri, Feb 18, 2022 8:13 pm
>>  Subject: Re: [Public-List] Charts and depth sounding
>>
>>  Hello Jim,
>>
>>  The Canadian Hydrographic Service continually re-surveys and updates charts through ’Notices to Mariners’.  This was once distributed by mail, more lately it has been available online, updated even more regularly.
>>
>>
>>
>>
>>  Gordon Laco
>>www.gordonlaco.com
>>
>>
>>
>>
>>
>>  > On Feb 18, 2022, at 8:10 PM, a30240--- via Public-List <public-list at lists.alberg30.org <mailto:public-list at lists.alberg30.org>> wrote:
>>  >
>>  >
>>  >
>>  > Gordon wrote
>>  > "My own opinion is that a depth sounder without a navigation chart is useless. The depth reading can be correlated with charted depths to help determine position? and THAT is what lowers the chances of going aground. Probably the most useful application of a depth sounder is when dropping the hook and determining how much anchor chain or rope needs to be let go.
>>  >
>>  > Two months till sailing? wahoo?"
>>  >
>>  > It might be worth noting that most charts, at least in the US for areas primarily used by small craft haven't been surveyed in a long time. While this isn't a major issue in places with hard bottoms, shallow water areas in the Chesapeake and along the US east coast haven't been surveyed in the lifetime of most skippers.
>>  > Also just because you have the newest chart plotter doesn't make it more accurate than the government charts the data is drawn from
>>  > Granted there is some updating when an individual or agency reports a change: dredged channel, bridge, marina, buoy location, etc.
>>  >
>>  > Jim Davis
>>  > Prairie Schooner
>>  >
>>  > Meddle not in the affairs of dragons, for you are crunchy, and taste good with ketchup
>>  >
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