[Public-List] Charts and depth sounding

[Gordon Laco]

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> 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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