There are a few fans here that might like to read this. We are all aware of the large number of accidents over the years and the comments below are worth a read.
svcrystalblues.blogspot.com/2017/09/navionics-sonar-charts-missing-reef.html
Thanks Ramona,
i was only debating this last night about what to use for an IPad type mapping software .
I think I might stick to using remote desktop off the PC down beliw running CMap charts.
navionics is great. He should have gone around the blue section. I never go across them even with high tide.
Though ive mostly been using binocs
And channel markers, navionics has been spot on.
I don't think a skipper should rely on 1source. I have some really old paper charts but even these show greyed out areas which warn me of shallow areas. I wouldnt attempt to go near these at night unless familiar with the area.
For me navionics works as long as i cross reference with other maps, eyes, Landmarks, markers etc.
When ive had to use navionics in bad weather or in the dark ive been lucky i guess.
Also lady musgrave details are omitted nearly everywhere including .gov charts. Google earth images are good.
I wonder if the 'NOT FOR NAVIGATION' Warning is limited to just the iPad?
But this error would certainly assist with explaining a very recent Post.
Also highlights that when you're navigating in confined/shallow/poorly charted waters, you need to fall back to navigating by all available sources of information.
Steve, while he was using the sonar chart for navigation, there was no 'blue area' it actually stated the charted depth as significantly deeper.
Select to expand quoteD3 said..
Steve, while he was using the sonar chart for navigation, there was no 'blue area' it actually stated the charted depth as significantly deeper.
True but i wonder if there are any indications of shallow water on other charts. To be honest i couldnt be bothered reading the guys drivel. Its too long. Seems like he just wants to blame navionics for his poor navigating.
I am going to rant:
Well, l could quote many of my and others' conservative posts on the 'vector vs. raster chart' issue and my comments of navionics and it's ilk, being kind of toys.
I wish, honestly wish l was wrong. But l am regretfully not.
I heard of uncharted or poorly charted areas, using AHO ( as well as Admiralty or NOAA ) paper or raster charts but we all have to give the tumbs up for the data they display. This includes the OFFICIAL Electronic Vector Charts used for professional navigation.
However, this is not including, unfortunately, the zillions of privately released charts, charting programs and applications chasing a lucrative market and quick bucks. Those charts and apps are mostly put together by people who have no experience - not serious professional knowledge and experience - or interest in the truthfulness of the data they project. How could they? They are simply operating a computer compiling data unlike the dedicated people of the AHO and other mapping bodies.
Data unaccountable, unreliable, untrustworthy and unchecked in many instances.
How could one in his right mind trust his pride and joy on data projected - like possible on navionics - by Joe Blow after his second bottle of booze or third reefer somewhere out there?
Most of this apps and chart programs create their 'competitive advantage' by displaying something not displayed by others using this fact as a selling tool. None of those marginal informations are necessary to navigate safely! Some of it might have some value but not at the cost of masking relevant information. That is relevant to safe navigation.
A foto of a geographical feature or other turistical info might be regarded as interesting the most, but not necessary for safe navigation and if it masks relevant navigational information, it is criminal.
Well, trust only official charts. I do.
Happy sailing! 
Select to expand quoteSectorsteve said..D3 said..
Steve, while he was using the sonar chart for navigation, there was no 'blue area' it actually stated the charted depth as significantly deeper.
True but i wonder if there are any indications of shallow water on other charts. To be honest i couldnt be bothered reading the guys drivel. Its too long. Seems like he just wants to blame navionics for his poor navigating.
Bet you wont find this sandbar on navionics!
All charts have errors, omissions and unreported changes. E- charts of various types at least have the benefit of automatic updating. How many people religiously add all the manual updates correctly and legibly to their manual charts?
Charts plus pilot guide plus eyeballs plus common sense gives a reasonable chance of success. Oh, and a bit of asking the locals.
Cheers
Bristle
Select to expand quotesirgallivant said..
I am going to rant:
Well, trust only official charts. I do.
Happy sailing!
Good luck with that. I have found AHO charts 800 meters out in longitude in one area. Actually, c=map was more accurate and confirmed by radar overlay..
Select to expand quotesirgallivant said..
Well, trust only official charts. I do.
Happy sailing!
We think alike sir g.
Select to expand quotePhoenixStar said..
Good luck with that. I have found AHO charts 800 meters out in longitude in one area. Actually, c=map was more accurate and confirmed by radar overlay..
Sign of a persistant navigator. Don't trust anyone except yourself and don't take his word as gospel either!! 
Navionics is pretty accurate. I ran aground last night right where it said .1. Spot on!
What is so hard about this.
Like the warning says, GPS is simply one aid to navigation.
Of course it has caused a huge deskilling of the boating population.
The gentlemen who fixes his position with radar as well is navigating and using an alternative means to fix position as he should do.
Also the arrogance of recreational boaters shows through.
Charts are not prepared for you.
There are prepared for commercial operations first of foremost.
Great example was Moreton Bay where until surveys in the late 1970s and early 1980s by Qld Transport, that part of the Bay south of the Shipping channel was still Derham's 1867 survey and a part was even a survey by Flinders.
No commercial traffic no need to survey.
Same on the West Coast of Tasmania, no commercial traffic and the big areas simply say inadequate survey.
also away from busy areas often the correlation between the chart on the screen and the land and indeed paper charts can be very poor.
Solution , plot the old fashioned way however is best, then take the lat and lon and place that on the electronic chart to check the error. Large error or not uncommon in remote areas. (but paper charts can have similar errors).
The point of good navigation is to use the best available methods (not one method) to fix a position.
On much of the east coast the most useful to fix position is the depth sounder given the bottom is so uniform.
I skirted around this blue area in between Panama and the Galapagos on my navionics chart. Cmap showed nothing nor did the paper chart but I made the detour around it just in case, I never figured out what it meant or if it was just charting mistake.
Select to expand quotelydia said..
What is so hard about this.
Like the warning says, GPS is simply one aid to navigation.
Of course it has caused a huge deskilling of the boating population.
The gentlemen who fixes his position with radar as well is navigating and using an alternative means to fix position as he should do.
Also the arrogance of recreational boaters shows through.
Charts are not prepared for you.
There are prepared for commercial operations first of foremost.
Great example was Moreton Bay where until surveys in the late 1970s and early 1980s by Qld Transport, that part of the Bay south of the Shipping channel was still Derham's 1867 survey and a part was even a survey by Flinders.
No commercial traffic no need to survey.
Same on the West Coast of Tasmania, no commercial traffic and the big areas simply say inadequate survey.
also away from busy areas often the correlation between the chart on the screen and the land and indeed paper charts can be very poor.
Solution , plot the old fashioned way however is best, then take the lat and lon and place that on the electronic chart to check the error. Large error or not uncommon in remote areas. (but paper charts can have similar errors).
The point of good navigation is to use the best available methods (not one method) to fix a position.
On much of the east coast the most useful to fix position is the depth sounder given the bottom is so uniform.
cant agree more hit a rock in tassie 2 years ago that wasn't shown on navionics current aus chart or cruising guide luckily was idling into anchorage at 3.5 knots so other than wounded pride a ding in the lead all was good .
grounding was entirely my fault approaching an unknown shore late in the arvo travelling near parallel to the shore though watching sounder didn't notice spine of rock on shore this projected 10 foot above sea bottom
finally its up to you and that is what makes it fun
Would the Crawford Navigation Atlas be an OK substitute for paper charts. Says it is based on Navy Hydrographic charts, but do you get the same level of detail and scale?
www.whitworths.com.au/bk-mariners-atlas-v1
The price of actual paper charts is rather scary.
Select to expand quoteboty said..lydia said..
What is so hard about this.
Like the warning says, GPS is simply one aid to navigation.
Of course it has caused a huge deskilling of the boating population.
The gentlemen who fixes his position with radar as well is navigating and using an alternative means to fix position as he should do.
Also the arrogance of recreational boaters shows through.
Charts are not prepared for you.
There are prepared for commercial operations first of foremost.
Great example was Moreton Bay where until surveys in the late 1970s and early 1980s by Qld Transport, that part of the Bay south of the Shipping channel was still Derham's 1867 survey and a part was even a survey by Flinders.
No commercial traffic no need to survey.
Same on the West Coast of Tasmania, no commercial traffic and the big areas simply say inadequate survey.
also away from busy areas often the correlation between the chart on the screen and the land and indeed paper charts can be very poor.
Solution , plot the old fashioned way however is best, then take the lat and lon and place that on the electronic chart to check the error. Large error or not uncommon in remote areas. (but paper charts can have similar errors).
The point of good navigation is to use the best available methods (not one method) to fix a position.
On much of the east coast the most useful to fix position is the depth sounder given the bottom is so uniform.
cant agree more hit a rock in tassie 2 years ago that wasn't shown on navionics current aus chart or cruising guide luckily was idling into anchorage at 3.5 knots so other than wounded pride a ding in the lead all was good .
grounding was entirely my fault approaching an unknown shore late in the arvo travelling near parallel to the shore though watching sounder didn't notice spine of rock on shore this projected 10 foot above sea bottom
finally its up to you and that is what makes it fun
Where was that Boty?
Select to expand quoteBlueMoon said..
Yes. Crawfords is an excellent substitute imho. So much easier to manage on a small yacht than the large roll of paper charts.
I never roll my charts. Fold but not roll.
