Garmin Navionics Sonar Charts

[PascalG]

Does anybody relies on and trusts Sonar Charts? Every time I try, I find them being useless because of their inaccuracy.

Right now I m anchored in 8’ of water with a foot of tide… yet crapionics shows water depth of 5’… I guess I m aground! And yes the 8’ sounding is accurate.

 

[boatbum]

I always used chartography as a guide. Depending on it for high accuracy is looking for trouble IMHO. It has to be difficult to maintain accuracy in shallow waters. It's not like they scan them after every storm etc..
I never expected the charts to accurately reflect depths in shallow water. Besides there is always the chance of a new obstruction. Heck one of our nukes found a lump in the bottom recently.

 

[PascalG]

I ve been anchoring in that spot for 30 years and depths haven’t changed at all.

The base NOAA charts are off by a couple of feet, showing 5’ MLW which is indeed fairly normal and accurate.

My point is that Sonar Charts are supposed to improve accuracy and they don’t. Every where I ve compared, they are always way off.

 

[Bob Ware]

I always used chartography as a guide. Depending on it for high accuracy is looking for trouble IMHO. It has to be difficult to maintain accuracy in shallow waters. It's not like they scan them after every storm etc..
I never expected the charts to accurately reflect depths in shallow water. Besides there is always the chance of a new obstruction. Heck one of our nukes found a lump in the bottom recently.

I do the same. Galveston Bay was a boaters nightmare following Ike until the GLO had the bay inspected by barges equipped with side-imaging sonar remove most of the debris.
We also have an ongoing problem with old oilfield pipe being dredged up by oyster boats and left dangling either just sticking out of the water or slightly under the surface.