[image] How accurate are nautical charts? Charts will provide more information on “zone of confidence” It is a major challenge – some might say an impossibility – to keep all thousand U.S. nautical charts up to date. But exactly how out of… Sometimes, partic…

From a quick look at the report it doesn’t seem to be a simple matter of the hazard being missing from the ECDIS chart. Seems to be related to the “Isolated Danger Symbol”. There’s been a lot of discussion about this: [Isolated_Danger] From 10 things they should have told you about ECDIS

I always assumed the 400-600 foot reading I got sometimes in waters charted at 6,000+ feet deep were thermoclines or plankton layers.

I agree, but lately I have been making myself use them all the time because the paper charts and their digital equivalents are going away. Vector charts introduce whole new layers of inaccuracies.

[image] yacht_sailor: Vector charts introduce whole new layers of inaccuracies. Why would that be the case?

I think you have that backwards, that’s why vector is useful on occasion.

Here is why: You may not understand the algorithm that determines how details come and go as you scale in and out. There was a multiple fatality some years ago that involved a boat on autopilot trying to sail through an island not visible when scaled out to about 100 miles. This stupid sailor tric…

[image] Kennebec_Captain: Why would that be the case? You answered your own question a few posts previously: [image] Kennebec_Captain: From a quick look at the report it doesn’t seem to be a simple matter of the hazard being missing from the ECDIS chart.

Both terms, “accuracy” and "layers’ have specific meanings wrt ENCs so I didn’t understand how vector charts could add layers of inaccuracies.

On standby at a rig for weeks, nothing to do so office says get all the charts out and update as vessel owner might pay a visit. Drag out lots of west coast africa. Updates are a few years out of date as boat has not been there. I knew how to use the chartco app so I was printing all the stuff, I…

How accurate are nautical charts?

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How accurate are nautical charts?

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