Navigation Challenges - Post Your Craziest Chart and Let’s Talk

[IslandHopper]

Read the text or listen closely to the podcast about the "Magenta" (Pink) line and the reason for it....it's interesting and educational...

The Intracoastal Waterway - The Magenta Line



https://oceanservice.noaa.gov/podcas.../dd56-icw.html

https://oceanservice.noaa.gov/podcas...4/dd022014.mp3

[sailingunity]

The Raymarine chart seems to have an extra green marker on it...

[Chotu]

Originally Posted by sailingunity

The Raymarine chart seems to have an extra green marker on it...

The three markers on the Raymarine chart that I underlined in red we’re not there in physical reality. Ha ha.

That made it even weirder.

And Boat man: you’re going to like this part. I don’t have a working depth sounder right now. Ha ha ha ha. I am running completely blind on depth. But I’m pretty used to that. Nearly every boat I ever owned has a broken depth sounder. Usually also broken radar. Never fails. Or actually it always fails.

So I did this little area with no depth sounder. Just the bottom of my boat to feel my way. No skipper Bob. Just my eyes and what you guys see in this thread. Ha ha ha.

[ChrisJHC]

Well, the first thing I would do would be to put the colours of the markers around the right way

Secondly, find out whether the depths are in feet or metres - probably not fathoms.

[Chotu]

Originally Posted by ChrisJHC

Well, the first thing I would do would be to put the colours of the markers around the right way

Secondly, find out whether the depths are in feet or metres - probably not fathoms.

Ah. That is in poor form for my initial post. I should have mentioned this. Those soundings are in feet.

[Chotu]

I suppose it’s time to put my route up.

Keep in mind that these markers didn’t exist. The green one at the bottom of the Raymarine chart and the next two on that chart were not there in real life which got me a little bit confused as I went through. Also the ones in this chart with my track were off station as well.

Things got a little sketchy at that hard turn where I am near the mud at the southern part of this picture. I was looking for markers and there weren’t any. Many of them were not there. So I continued a little too long in that direction and had to make a pretty hard turn to get to the 8ft trench.

I didn’t touch bottom. But I don’t have a sounder either. I draw 3 feet with the rudders down and able to steer.


Like Chuck, I went wide.

My reasoning was that areas dig out in a bend often continue to some extent. Contours.

So you can see my track followed the contour around the outer edge of that turn.

My feeling is that if you took the inside of that turn, it’s more likely that there was a piece of land/shallow in that unsounded area between the small round island and the rest of the mud to the north.

But the depth contour that I followed should be the deepest water in that particular turn. That was my logic.

I was happy it worked.I still didn’t make new fuses for my kick ups yet. This one had me nervous.

[requiem]

Originally Posted by Chotu

My feeling is that if you took the inside of that turn, it’s more likely that there was a piece of land/shallow in that unsounded area between the small round island and the rest of the mud to the north.

But the depth contour that I followed should be the deepest water in that particular turn. That was my logic.

Agree, I would have suspected a path from the 5' to the 4' sounding for the same reason.

That said, I'd also have pulled out Navionics, because as much as I have issues with it, it has far more detail in shallow inland areas like this than the NOAA charts.

[Pandor]

Originally Posted by Chotu

My feeling is that if you took the inside of that turn, it’s more likely that there was a piece of land/shallow in that unsounded area between the island and the rest of the mud to the north.

But the depth contour that I followed should be the deepest water in that particular turn. That was my logic.

I was happy it worked.I still didn’t make new fuses for my kick ups yet.

But you made your decision without the best available information. The latest NOAA encs show a very clear dredged channel with a min depth of 11.8 feet (dredged Sept 2021).

[Pandor]

And the depths are confirmed by the ACE overlays. Your path was unnecessarily risky.

[Chotu]

Originally Posted by Pandor

But you made your decision without the best available information. The latest NOAA encs show a very clear dredged channel with a min depth of 11.8 feet (dredged Sept 2021).

That’s quite a chart. None of those markers were there. None. I don’t know where they are getting this information from. 113, 112 and 111 were not there. It was just empty.

Also, where is the round, dry spot?

I’m already running the latest NOAA raster chart and the latest Raymarine chart. How many more charts can a person look at at once? 2 seems to be more than you’d need except in this particular spot.

[Chotu]

Originally Posted by Pandor

And the depths are confirmed by the ACE overlays. Your path was unnecessarily risky.

What the hell is an ACE overlay? I like it.

That would have been pretty helpful.

Typically I’m not in this kind of crap. I sail in places that stay the same for thousands of years normally. The ACE overlay looks great for the ICW.

[Chotu]

Looking forward to the next one. I hope people put theirs up in this thread also. It’s fun.

[Lodesman]

It would help to reconcile your shots against Pandor's if you showed North; from the looks of it yours are west up. Clearly green 111 has been moved. Is there an NTM that refers to this? To my mind, you should have left 111 to stbd.

[Lodesman]

For those satellite pics, where do you get them? Do you know when they were valid? Same with the other overlay data?

[ranger58sb]

Originally Posted by Chotu

What the hell is an ACE overlay? I like it.

That would have been pretty helpful.

Typically I’m not in this kind of crap. I sail in places that stay the same for thousands of years normally. The ACE overlay looks great for the ICW.

US Army Corps of Engineers (USACE). Survey data. Available in AquaMap.

Looks like Pandor's survey image is from Waterway Guide.

-Chris