UK vector charts

Sorry, I think a lot of this has probably been asked before, but the three threads I find don't quite address my questions.

I am starting out with a newly acquired boat, and putting together a Linux-based navigation computer. I would like to make the right decisions from the start and spend money wisely on charts etc. but am lost amid uncertainties. For navigation software, my choices appear to be OpenCPN and qtVlm; other things being equal, I much prefer qtVlm, but am struggling to work out which charts I would use with it for the UK (mainly the west coast). The visitmyharbour rasters are very affordable, but I believe that to take proper advantage of a computer for navigation one should use vector data (depth alarms, tide information etc.). qtVlm supports S63 charts, but the only suitable looking source I've found are C-Maps which seem to require a Windows system for updates, and even at half the cost of initial purchase, updates are expensive!

The questions this raises are:-

1. Does qtVlm calculate optimum course to steer based on tidal current information, i.e. compute the anticipated tidal set during the leg based on anticipated speed and produce a heading from the start point which offsets that (I see various hints online that it does, but nothing in the manual to corroborate this)? If so,
   • Does it use tidal information from the chart when available in this calculation?
   • Can it instead use tidal current information from grib files?
2. Are there S63 sources for the UK other than C-Maps which are more suitable?
3. If C-Maps are the best option, is there a way to get their updates without a Windows machine?
4. Are there any other sources/types of vector chart available for qtVlm?

I also don't entirely understand the S63 licensing model. I've read the qtVlm page on user permits and activation: 3 activations per user permit, but charts can only be used with qtVlm. Does this mean it's possible to purchase a single set of charts, then use them through qtVlm on three separate devices, but not with other software on any of those devices? Is this the same for all S63 providers? Is it possible to invalidate an activation code and then re-activate the charts on a different machine? The S63 charts I've found are too expensive to risk losing them because something happens to the hardware they're licenced on.

 

Hi,
Some short answers:
1) Yes, but the only data it can use is a grib file containing Currents (it will not use harmonics nor Currents data included in a vector chart).
2) We cannot read C-Maps. Our UK users mainly use chartworld S63 charts, compatible with all our platforms (Windows/Mac/Linux/Raspberry/Android/iOS).
4) For this area no at the moment (apart from outdated old CM93s). That may change eventually.
The S63 mechanism is driven by IHO rules. You buy a permit that allows you to buy S63 chart for a particular machine (actually 3, but the 2 others are supposed to be a backup). You can purchase and install as many charts as you want with your permit, but if you need a fourth machine then you must purchase a new permit, and therefore all your charts also since they will not be allowed for this new permit. A qtVlm permit can be used only with qtVlm, this is again an IHO rule.
--Philippe

Thank you maitai,

That's really helpful. I saw "qtVlm can use S63 charts purchased from any S63 official provider" and that C-Maps were S63, and assumed it could use C-Maps. I suppose C-Maps aren't "official", but Chartworld ones are resold official charts, even though Chartworld themselves aren't a government organisation. Have I got that right? My head is starting to hurt.

I have looked at Chartworld, but couldn't get anything as useful as a price out of their website without registering and providing hardware IDs etc. which I don't yet have. Can you tell me what the system is for their updates?

I think that since qtVlm uses grib files for tidal routing rather than relying on the chart, all I'll really be losing on a day-to-day basis by running raster charts is the possibility of bathymetry-related alarms. So, I'm probably best starting off with visitmyharbour raster charts, getting used to the system, and then buying a couple of Chartworld charts for my local area as an experiment. Does that sound like a sensible approach?

 

Hello ajl199,
You can read this excellent David Burch's article about S63 and how to use it on qtvlm :
davidburchnavigation.blogspot.com/2022/0...d-international.html
You will find links to Youtube videos on how to deal with S63 step by step.

Raster charts and Vector charts are 2 completely different worlds. It is not only about bathymetry alarms, but also all other sorts or danger detection and details. Indeed plenty of explanations in David Burch videos and blog.

Note that when you purchase a S63 you purchase it for a period meaning that during that period you can update the chart free of charge. After that period qtVlm will warn you that your charts are potentially outdated but you can still use them.
As for the cost I don't remember it depends a lot on the chart itself.. As I can see from here www.chartworld.com/shop/off_enc it is around 31€ per chart. (select UKHO as a producer).