[Public-List] Public-List Digest, Vol 4283, Issue 3

[Gordon Laco]

Hello Stephen, 

No, the chart is updated monthly as Notices to Mariners comes out… annually incorporating new information.  New surveys are conducted continually.


Gordon Laco
426 Surprise





> On Feb 19, 2022, at 10:39 PM, Stephen Gwyn via Public-List <public-list at lists.alberg30.org> wrote:
> 
> 
> Hi Gord,
>> 2201 is just the inland route strip chart? the one for our end of Georgian Bay is 2241 and was issued as a brand new chart reflecting the new survey not long ago.  2241 replaced the older chart.
> So 2201 is based on a 1968 survey and only got replaced "not long ago"? So every 50 years?
> My chart 3313 was discontinued recently, based on a 1992 survey, that's 25 years.
> It replaced 3310, surveyed in the early 70s, discontinued in the 90s, that's 20-25 years.
> I wouldn't call a 25+ year cycle "regular re-surveying".
> 
> Hi R Kirk,
>> So you're lower on the totem pole than Sable I, James Bay, North Slope, etc. Wonder why they outshine you? More valuable, or just that they haven't been done in a while. also wonder why they do that far offshore area?
> You'd have to read the full article:
> https://www.mdpi.com/2220-9964/7/7/240/pdf
> which discusses methodology but not specific
> locations.
> 
> The following are educated guesses:
> 
> Sable Island, because it moves and because it's wrecked a lot of ships,
> 
> James Bay, Hudson Bay because it's poorly surveyed,
> and becoming more important as the arctic stays
> ice free longer; There is talk of making Churchill,
> Manitoba a major port.
> 
> Not sure about North Slope.
> 
> Looking this up lead me down a Google hole to this site:
> https://data.chs-shc.ca/map
> which has all the available Canadian bathymetry available for download.
> Not legal (or useful) for navigation, but cool none the less.
> The CHS (unlike NOAA) does not make their charts available
> online for free. This is as close as it gets.
> 
> SG
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