Navionics - A Childrens Toy?

[rslifkin]

Going into anywhere unknown, I like to have charts from 2 different sources up, particularly if it's not a case where I know ahead of time that "chart X is the best there is for this area". To me, if the 2 charts disagree on anything important, it's time to use my eyes and any other resources available to determine which is more accurate. And if I can't tell, then proceed with caution.

[conachair]

Originally Posted by carstenb

well, we've been at sea for close to four years now, sailed over 25k nm and we have yet to find decent internet in any bar/coffee shop etc - certainly not fast enough for downloading google earth or similar.

But maybe we'e just unlucky. Here in Hawaii we've purchased an american phone and phone plan so we do have decent internet her but this is the first time

SASplanet is not Google earth. The download rate is very slow anyway even on a fast connection, it's not like trying to watch HD YouTube. If you have enough speed to get on here then you can download the images, just sip your coffee a bit slower, it will get there.
Been drifting around onboard for a decade and a half now, web access just gets better and better, there's always a way

[conachair]

Originally Posted by CassidyNZ

You probably have state-of-the-art chart plotter that overlays pictures on charts along with AIS and radar and your DNA profile. I don’t have one of those. Even if I could get a satellite picture on my boat I still wouldn’t know where in the picture my boat was at any given time so what would be the point?

Are you cruising with no laptop?

[arsenelupiga]

Originally Posted by CassidyNZ

Well, I don’t know about that - I’ve been sailing for quite a long time, have been voyaging intercontinentally for four decades, have visited dozens of islands in three different oceans and I haven’t had a chart run me into trouble yet. Curiously, thousands of sailors through the ages have successfully relied on marine charts. Now suddenly they’re deemed to be dangerous.

My only reservation is Navionics in Fiji which has some glitches but the paper charts for that area are not great either so their resources are probably limited. But this is well known and as long as you know the shortcomings and plan for them, it’s all good. I surely wouldn’t want to use satellite pictures in that area either.

But that’s just me.

You probably have state-of-the-art chart plotter that overlays pictures on charts along with AIS and radar and your DNA profile. I don’t have one of those. Even if I could get a satellite picture on my boat I still wouldn’t know where in the picture my boat was at any given time so what would be the point?

you are a lucky man.

Here is beauty for you from east coast australia. Underwater rock west of Great Keppel Island is 114m away on map from real position. We can only hope you keep your luck. Maybe get laptop and download all pics before going to travel ...

[Simi 60]

Originally Posted by CassidyNZ

Well, I don’t know about that - I’ve been sailing for quite a long time, have been voyaging intercontinentally for four decades, have visited dozens of islands in three different oceans and I haven’t had a chart run me into trouble yet. Curiously, thousands of sailors through the ages have successfully relied on marine charts. Now suddenly they’re deemed to be dangerous.

My only reservation is Navionics in Fiji which has some glitches but the paper charts for that area are not great either so their resources are probably limited.

By your own admittance you acknowledge the charts in some areas leave a lot to be desired.
Logic says they can lead you into trouble if you trust them as your only source

But this is well known and as long as you know the shortcomings and plan for them, it’s all good.

And if you dont know their shortcomings?
Amd how do you plan for their shortcomings? Tea leaves? Chicken bones?
Surely Sat images would be better.

I surely wouldn’t want to use satellite pictures in that area either.

Better than dodgy paper, tea leaves and chicken bones.

But that’s just me.

Most likely

You probably have state-of-the-art chart plotter that overlays pictures on charts along with AIS and radar and your DNA profile. I don’t have one of those.

Nope.
$150 2nd hand mini pc
$100 monitor
$15 usb gps puck
and opencpn

And an equally cheap and dated laptop as one of several backups.

Even if I could get a satellite picture on my boat I still wouldn’t know where in the picture my boat was at any given time so what would be the point?

On opencpn you'll be the big red boat icon moving across the screen, hard to miss.

[El Pinguino]

I can't really see myself spending all that time and effort putting sat images onto OpenCPN...

What I can see myself doing is comparing sat images with my charts.
(This is of course based on the assumption that the L/L on Google is accurate.... )

Open area of interest on OCPN .. in this case using CM93 cartography... note lat/long of a salient feature ... I used the stbd hand light in the entrance... shows on both CM93 & GE...
Open Google Earth ...check L/L of feature...
(In this case the two were a match.. another location further south there was a 1.2 mile discrepancy even using iSailor.....)

Save the google harbour plan as a Jpeg... in my case I put it in 'photos'.
Quick and easy... ( First 2 pics..)

Mind you there are some places where GE is as much use as teats on a bull and just isn't going to work but you will be navigating by eyeball there anyway... 3rd and 4th pics...

[snotter]

All, I’ve been immensely enjoying the conversations about incorporating satellite imagery into navigation. On my boat I use an equated ray e-80 with an iPad mini velcroed next to to the mfd. The mini is always plugged in and charging. I use Navionics on both the mfd and mini. When coastal cruising Florida and the Gulf coast away from my home port I always do a chart update as soon as my iPad mini when coming in to a marina or approaching

[snotter]

Sorry for the above post—I accidentally sent it prematurely. How can I use satellite images and be able to toggle quickly between the navionic charts and sat image on my iPad mini?

[Simi 60]

Originally Posted by El Pinguino

I can't really see myself spending all that time and effort putting sat images onto OpenCPN...

What I can see myself doing is comparing sat images with my charts.
(This is of course based on the assumption that the L/L on Google is accurate.... )

Open area of interest on OCPN .. in this case using CM93 cartography... note lat/long of a salient feature ... I used the stbd hand light in the entrance... shows on both CM93 & GE...
Open Google Earth ...check L/L of feature...
(In this case the two were a match.. another location further south there was a 1.2 mile discrepancy even using iSailor.....)

Save the google harbour plan as a Jpeg... in my case I put it in 'photos'.
Quick and easy... ( First 2 pics..)

Mind you there are some places where GE is as much use as teats on a bull and just isn't going to work but you will be navigating by eyeball there anyway... 3rd and 4th pics...

Proper use of opencpn/sasplanet would most likely provide superior results.

For starters you get a choice of half a dozen satellite sources at different times of the day.
Secondly the images are georeferenced so you see yourself moving across the satellite image
Thirdly, with version 5 split screen you can toggle between 3 versions of actual charts cm93, cMap, navionics, the last 2 available on sasplanet, running on one side and satellite images on the other.

[carstenb]

Well you fellas have gotten beyond my meagar talents with everything you seem to be able to do.

I have a chartplotter, OpenCPN on a PC and Maxsea on a PC.

I do not download SAsplanet, Google earth or the like simply because where we cruise there is no internet capable of downloading pictures at speed. We consider ourselves lucky to be able to download predict wind .

We're on Maui right now and here we do have high speed internet. But most other places we don't

My original question was - Is Navionoics just a childrens toy? We've used C-map and Maxsea everywhere we've sailed for the past almost 4 years and don't have any complaints regarding their accuracy.

But Navionics so far is wildly inaccurate - So is this just us or should we just junk the Navionics and buy C-map instead ?

Anyone who has sat on HIva Oa or the like and waited for an hour for a local Predictwind to download knows what I am talking about when I say no internet. Anyone whho wnat s ot try can sail to Fatu HIva, go up to the only place that has wifi (the only restaurant) and wait while their forecast downloads

We are not sailing in Florida or San Francisco Bay

[Simi 60]

As a general rule, all electronic charts are only as good as the paper they came from.
I run a real version of Cmap, it has errors, I run a real version of navionics, it has errors.
Open cpn with sat imagery generally shows these errors up quite dramatically.

I do not download SAsplanet, Google earth or the like simply because where we cruise there is no internet capable of downloading pictures at speed. We consider ourselves lucky to be able to download predict wind .

I plan on going through North QLD, Northern Territory and onto South East Asia in the near future.
While I have good mobile data I have been in a mbtile frenzy taking satellite imagery of every likely anchorage , near reef and headland where charts are lacking.
AND making several backup copies of those as well.

Doing it on the fly with patchy reception is not the time to do it.

[Jim Cate]

Originally Posted by arsenelupiga

you are a lucky man.

Here is beauty for you from east coast australia. Underwater rock west of Great Keppel Island is 114m away on map from real position. We can only hope you keep your luck. Maybe get laptop and download all pics before going to travel ...

You might want to swing your compass or perhaps review basic charting... that rock is EAST of GKI, not WEST!

Jim

[arsenelupiga]

Originally Posted by Jim Cate

You might want to swing your compass or perhaps review basic charting... that rock is EAST of GKI, not WEST!

Jim

Well done. I was testing if anyone will read that bit

Picked that up after made my route and run it thru satellite photos as I always do these days. Original path that I designed in Navionics went over that rock. Could still get lucky if tide was high or pass when on top of wave. But one get lucky only sometimes.

[tekdiver]

Originally Posted by mikedefieslife

From you post Navionics, NOAA, and C-map are all different. Why would you buy C-map over Navionics it is also different from NOAA which you'd like to presume is official?

Also depending on the screens you are looking at Navionics can the current depth for the time of tide, rather than the mean low water depths. Also all community edits can be turned off.

Any way to check what Garmin has for that area, I wonder if that too is different. Which one do you trust?

Just bought a garman and it is loaded with N avionics and tides and currents Putting it in this weekend as well as doing new Isinglass to camper cover will be busy.

[KetchJohnB]

Originally Posted by wrwakefield

Carstenb,

We primarily use Navionics+ in our two B&G Zeus2 chart plotters plying South-Central and Southeast Alaska waters.

We update when we can [typically every few months] and find the charts to be accurate in most instances. On occasions where someting is missing [or only exists on the chart...] I cross reference against NOAA raster charts and often- but not always- find a similar error.

On edit: I should note we rarely use or trust the Navionics 'SONAR' chart info. Currently there seems to be too much interpolation [in our area anyways...] to trust our boat to it...

We also use C-Map charts, [with our two plotters with 2 SD card slots each, we can currently use 4 seperate chart sources on each...] Sometimes I run Navionics and C-Map splitscreen [side-by-side, same scale] when transiting tricky waters for the first time. [e.g., Keku Straight AKA Rocky Pass...] to determine which is best-of-breed for that area.

The reason for having both Navionics and C-Map is I have found over time that sometimes Navionics has better detail, and other times C-Map excels. Oftimes they are close to the same. [We reinforced this to ourselves while scrutinizing/planning routes and anchorages through the NW Passage— though we have not transited those waters yet...]

Most of the time when one chart source lacks detail, the other makes up for it, so Navionics/ C-Map is a good combimation for us.

As a hedge, we always have NOAA raster charts running in SeaIQ on a tablet, and available on Open CPN on a laptop. We cross compare frequently [there is a tablet next to each chart plotter at both helms...] and feel this is necessary to continue successfully missing the hard bits around the edges up here... [Forwars facing SONAR is very useful in these waters...]

We will truly miss the raster charts should NOAA follow through and deprecate them as currently being discussed.

I hope some of this is useful for you.

Cheers! Bill

PS: We typically overlay RADAR on the chart[s] to confirm chart accuracy. We rarely note any discrepencies.

PPS: It is important for other readers to note we are not talking about the Navionics app running on portable devices. My comments pertain to Navionics+ charts run on a chartplotter. [MFD]

We have taken Bills approach. Use a couple of sources. We are down in Central America. Land is "bad" down here and you have to approach a poorly charted anchorage (which is all of them) with the sun at your back to see the reefs. We use a B&G Zeus3 with Navionics+, OpenCPM and have C-Maps. Garmin charts down here have been way off at times, so we retired that chart plotter. As Garmin just purchased Navionics, this will change.


Best,

John