Which chart provider

[Whaup367]

I use Imray paper and Imray Navigator app on my iPad. Love it.

The Imray Navigator app references raster charts... do they enable display of survey dates, please?

If so, does anyone know if they can they be loaded onto a Raymarine MFD? There's a piece from Imray on their website advertising compatibility in Nov 22 but the link to available products is empty.... confusing.

 

[dunedin]

If so, does anyone know if they can they be loaded onto a Raymarine MFD? There's a piece from Imray on their website advertising compatibility in Nov 22 but the link to available products is empty.... confusing.

There have been a lot of different Raymarine MFD's so you need to be more specific which type you have (and which version of Lighthouse software) unless planning to buy new.

 

[Sandy]

A2 prints from my local shop are about £4 a go, so the price is not unrealistic.

I suspect that the rise of Navionics means far fewer people buy paper charts.
Imray have gone into direct competition with the folio format.
The market is not what it was.

How up to date are your A2 prints?

Being an old fuddy duddy, I like my paper charts, I also have a chart plotter, but find the chart plotter is rubbish for seeing the 'big picture' when passage planning.

A few years ago I double handed a 600 NM coastal passage. I used charts and my co-skipper used Navionics. The passage plan was done in about the same time, the passages were very similar. The major difference was that the other skipper had his head in his phone working out where we were all the time, while I knew roughly where we were.

The take away I had from that trip was that by using paper I could see more information and that was remembered.

I am reluctantly replacing all my Admiralty charts with Imray, sadly the NV charts that I like are now uneconomic since we left for a parallel universe in 2016, as after using Admiralty for 40 years Imray's colours are all wrong.

 

[st599]

A2 prints from my local shop are about £4 a go, so the price is not unrealistic.

I suspect that the rise of Navionics means far fewer people buy paper charts.
Imray have gone into direct competition with the folio format.
The market is not what it was.

Which is fine, unless you're coded. If coded, you need paper charts from a recognised vendor or an ECDIS system and it's dual redundant power supplies, large screen, redundant sensors etc.

 

[Whaup367]

There have been a lot of different Raymarine MFD's so you need to be more specific which type you have (and which version of Lighthouse software) unless planning to buy new.

Good point... but academic unless the Imrays display important information that isn't available on Navionics?

 

[SaltyC]

See post #16 above.

Working out the price of replacing SC 5611.

£15 * 28 = £420 * 25% = £105.00

Last time I bought the set it was £44.00.

One advantage is you may not need ALL the charts of an Admiralty folio, depending on your boat / draft etc some sheets will be unnecessary to order reducing the cost.
I still, cynically, feel the change will reduce demand and thus justify their withdrawal.

 

[Sandy]

One advantage is you may not need ALL the charts of an Admiralty folio, depending on your boat / draft etc some sheets will be unnecessary to order reducing the cost.
I still, cynically, feel the change will reduce demand and thus justify their withdrawal.

Suppose, it depends what type of sailing you do.

 

[PhillM]

See post #16 above.

Working out the price of replacing SC 5611.

£15 * 28 = £420 * 25% = £105.00

Last time I bought the set it was £44.00.

Not arguing about the cost issue, but there are a lot of charts in each portfolio I doubt I would ever use. So, take the most useful from two to three portfolios and the price works out the same.

 

[B27]

Not arguing about the cost issue, but there are a lot of charts in each portfolio I doubt I would ever use. So, take the most useful from two to three portfolios and the price works out the same.

Or maybe club members could order some sort of selection?
If you can find half a dozen people who want the local chunk of coast and a couple of rivers, you've on the way to getting a fair price?

 

[dunedin]

Which is fine, unless you're coded. If coded, you need paper charts from a recognised vendor or an ECDIS system and it's dual redundant power supplies, large screen, redundant sensors etc.

Absolutely. And MCA have some legal SOLAS requirements for the UK. Hence the push back to UKHO’s announcement of worth drawing all paper charts by 2026. Although UKHO apparently have no formal requirement to provide a solution for coded vessels, MCA has and hence needs a solution before UKHO paper is finally withdrawn, no sooner than 2030.

 

[dunedin]

One advantage is you may not need ALL the charts of an Admiralty folio, depending on your boat / draft etc some sheets will be unnecessary to order reducing the cost.
I still, cynically, feel the change will reduce demand and thus justify their withdrawal.

Yes, make more difficult to buy (Folios no longer available from any chandleries) and then say demand has dropped. Surely not ?

 

[Buck Turgidson]

The Imray Navigator app references raster charts... do they enable display of survey dates, please?

If so, does anyone know if they can they be loaded onto a Raymarine MFD? There's a piece from Imray on their website advertising compatibility in Nov 22 but the link to available products is empty.... confusing.

I can't find survey dates but as they are updated regularly from UKHMO and other national HOs the answer is surely. "the latest available" as it is for all charts.

 

[SaltyC]

Yes, make more difficult to buy (Folios no longer available from any chandleries) and then say demand has dropped. Surely not ?

Aah - another cynic!

 

[Bristolfashion]

The better pilot guides, such as the Irish cruising club, make useful comments about the accuracy (or otherwise) of paper & electronic charts. A 100 year old survey of rocky coastline could be pretty accurate, but last week's survey of Wexford entrance may not be.

 

[Whaup367]

I can't find survey dates but as they are updated regularly from UKHMO and other national HOs the answer is surely. "the latest available" as it is for all charts.

Thanks for the info. Appreciated.

My concern is that on the chartplotter, it's impossible to tell whether that "latest survey" was a few years ago from a gps located sonar ship or a hundred and fifty years ago from a lead line pulling boat with a handbearing compass.
For example, if I were to sail from Stornoway to Loch Mharabhig (an interesting looking nearby anchorage), I would pass from a 2008-2012 survey around Stornoway into an 1835-1928 surveyed area as I enter the Loch and I'd like to know that.

Obviously, I know to check charts (paper or on tablet) as part of passage planning etc so I ought not to get caught out but if there were an alternative chart source that made this data easily accessible at the helm I'd be interested in adopting it.
... and I hear rumours that there are sailors that use vector charts on chartplotters as their only navigation aid. Hopefully they will never be unlucky enough to find a pointy gap in the data or a shoal that's shifted it's contours in the hundred years or so since the data was refreshed.

 

[AntarcticPilot]

Thanks for the info. Appreciated.

My concern is that on the chartplotter, it's impossible to tell whether that "latest survey" was a few years ago from a gps located sonar ship or a hundred and fifty years ago from a lead line pulling boat with a handbearing compass.
For example, if I were to sail from Stornoway to Loch Mharabhig (an interesting looking nearby anchorage), I would pass from a 2008-2012 survey around Stornoway into an 1835-1928 surveyed area as I enter the Loch and I'd like to know that.

Obviously, I know to check charts (paper or on tablet) as part of passage planning etc so I ought not to get caught out but if there were an alternative chart source that made this data easily accessible at the helm I'd be interested in adopting it.
... and I hear rumours that there are sailors that use vector charts on chartplotters as their only navigation aid. Hopefully they will never be unlucky enough to find a pointy gap in the data or a shoal that's shifted it's contours in the hundred years or so since the data was refreshed.

There's no reason to assume that a 19th-century survey is any worse than a modern one; indeed, it may well be better and more detailed in inshore waters. I know of people who deliberately carry old versions of charts of those waters because modern ones are less detailed! The only case where that's not true is where there are shifting shoals and mud banks - not usually a factor on the West Coast of Scotland. However, the 19th-century survey will be fixed relative to survey points on land, and the absolute positioning may not be as good as a modern survey, though it will have been adjusted to fit WGS84. However, significant residual errors may still remain. But they will be absolute errors, not relative, so navigating with respect to visible features rather than absolute positions is essential.

I entirely agree that a failing of modern chart plotters is that they do not carry information about the source of data. It can be done - if you look at CM93 data in OpenCPN, you will find that full metadata is available for every feature. The source vector data from the HO certainly carries full metadata for every feature; it is a part of the S63 (or successors) standard. However, it's not a vector/raster distinction; in fact, the original vector data carry far more information about the provenance of a feature than the broad brush survey diagrams that you are checking. But representing such information cartographically is difficult, and the existing standards for charts don't encompass it except in the broadest way. I suspect that the lack of availability of provenance data is a hang-over from the early days of chart-plotters, where storage space and processing power were limited.

 

[B27]

Thanks for the info. Appreciated.

My concern is that on the chartplotter, it's impossible to tell whether that "latest survey" was a few years ago from a gps located sonar ship or a hundred and fifty years ago from a lead line pulling boat with a handbearing compass.
For example, if I were to sail from Stornoway to Loch Mharabhig (an interesting looking nearby anchorage), I would pass from a 2008-2012 survey around Stornoway into an 1835-1928 surveyed area as I enter the Loch and I'd like to know that.

Obviously, I know to check charts (paper or on tablet) as part of passage planning etc so I ought not to get caught out but if there were an alternative chart source that made this data easily accessible at the helm I'd be interested in adopting it.
... and I hear rumours that there are sailors that use vector charts on chartplotters as their only navigation aid. Hopefully they will never be unlucky enough to find a pointy gap in the data or a shoal that's shifted it's contours in the hundred years or so since the data was refreshed.

I think, if you need to be worrying about ultrafine detail and the provenance of the data while you are underway, you should have a big crew to be actually sailing the boat and keeping a lookout.

What happened to having a passage plan and keeping a safe distance from hazards?

People seem to have come to expect accurate detail which lets them get 10ft from the rocks everywhere, whereas 25 years ago we were happy to use GPS to keep us in safe water.

Users should be realistic about their expectations and how much they trust not only the data, but also their GPS.
Ever been in a car and had the satnav decide you're on the country lane parallel to the motorway?

It's nice to use the detail to avoid needing to go outside cardinals for example, but it's not essential and a certain amount of planning ahead might help?

 

[AntarcticPilot]

There's no reason to assume that a 19th-century survey is any worse than a modern one; indeed, it may well be better and more detailed in inshore waters. I know of people who deliberately carry old versions of charts of those waters because modern ones are less detailed! The only case where that's not true is where there are shifting shoals and mud banks - not usually a factor on the West Coast of Scotland. However, the 19th-century survey will be fixed relative to survey points on land, and the absolute positioning may not be as good as a modern survey, though it will have been adjusted to fit WGS84. However, significant residual errors may still remain. But they will be absolute errors, not relative, so navigating with respect to visible features rather than absolute positions is essential.

I entirely agree that a failing of modern chart plotters is that they do not carry information about the source of data. It can be done - if you look at CM93 data in OpenCPN, you will find that full metadata is available for every feature. The source vector data from the HO certainly carries full metadata for every feature; it is a part of the S63 (or successors) standard. However, it's not a vector/raster distinction; in fact, the original vector data carry far more information about the provenance of a feature than the broad brush survey diagrams that you are checking. But representing such information cartographically is difficult, and the existing standards for charts don't encompass it except in the broadest way. I suspect that the lack of availability of provenance data is a hang-over from the early days of chart-plotters, where storage space and processing power were limited.

Incidentally, one place where the chart DOES depict uncertainty is at the Tail of The Bank, opposite Greenock! There is a line across the chart with the annotation "Surveys on either side of this line could not be reconciled". That's as near to "Here be Dragons" as I've seen on a modern chart!

 

[Whaup367]

... Obviously, I know to check charts (paper or on tablet) as part of passage planning etc...

...What happened to having a passage plan and keeping a safe distance from hazards?

?

People seem to have come to expect accurate detail which lets them get 10ft from the rocks everywhere, whereas 25 years ago we were happy to use GPS to keep us in safe water.

The anchorage in question has an excellent Antares survey, which allows this: in fact IIUC, one of the main reasons Bob set out to publish the charts was to enable those of us with less experience and confidence to access some of these glorious locations safely.

My point is not that the information is unavailable nor unreliable but that access to it is not facilitated by the major marine electronics suppliers and the chart providers they work with. They don't even need to increase the amount of data they have access to, just present something they are currently omitting, so that users know to take extra care, or find alternatives.

Users should be realistic about their expectations and how much they trust not only the data, but also their GPS.

Exactly so: it's very easy to be drawn into a false sense of security when a sophisticated chartplotter shows you your precise location, clear of well defined hazards. The issue is that the precise location may not be accurate, nor the well defined hazards correctly charted... and it would be helpful to have an easily accessible way to assess the accuracy of what's presented (particularly when it's out of sight!).

...It's nice to use the detail to avoid needing to go outside cardinals for example, but it's not essential and a certain amount of planning ahead might help?

Indeed: but one of the key points of this thread is that such planning is being made more difficult by the withdrawal of a data source that used to provide it at reasonable cost; and one of the issues is that this data is not even available to the user on some of the tools most commonly used for the job.

 

[ColinR]

My question is about digital charts, though, not printed. Are either of these available on a chartplotter; and if so are the survey dates accessible?

the Memory-Map app runs on Android or Ipad and you can buy all the latest Admiralty charts of the UK for about £20 (or maybe a bit more?) for a year for the lot. They are raster charts but I often have them running alongside the chartplotter as they can give better detail and a familiar interface. After all they are the source of the data on the chartplotter. If your device has GPS it will show your position and track like a chartplotter. If you want to go into Scottish waters you can also use the incredible large scale Antares charts on Memory-Map.