Recent Posts

The end of Windows XP

by Andrew Nibbs 29 June 2015 13:16

Windows XP was last released by Microsoft in 2001 and they stopped supporting it in 2009. They continued "extended" support until April 2014 - that means they kept fixing security holes. Now they don't fix security problems and it's less of a good idea to use it. 

We are now seeing Microsoft's software development tools (which we use) abandoning support for XP and that is forcing us to soon stop supplying software that will run on XP. 

SagePay who provide our payment handling services no longer trust Internet Explorer on XP as providing sufficiently secure internet communications. People wanting to buy Nuno or charts on XP should use Firefox or Chrome browsers instead. 

If you are using XP you should seriously consider replacing it - not least because Windows is much better now than in 2001!

For now - Nuno does still run on XP including the latest release Nuno The next release almost certainly won't.

SeaWork 2015

by Andrew Nibbs 21 May 2015 14:51

We'll be at SeaWork 2015, the commercial and marine workboat show in Southampton. The show runs from Tuesday 16th June through to the 18th. Come and see our 2m by 2.5m chart of the UK or at least come and find out if I messed up the artwork order.

We'll (hopefully) have Admiralty pens and CHERSOFT M&Ms (supplies are limited).

SeaWork is at ABP Port of Southampton -


Nuno on a Mac 2

by Andrew Nibbs 22 April 2015 14:17

Now there is a new way to use Nuno on a Mac. A single download that contains Nuno, UK charts and the ability to run the software on Mac OSX without requiring you to buy a Windows licence and do any other setting up.

It works by using a software project called "Wine" that allows Windows application to run on Unix type OSs like Linux and Mac OSX. You don't need to know about Wine but here's the wikipedia entry.

Alternative (Running real Windows)

This isn't what this post is about, but:

The other way to run Nuno (and Windows software in general) on your Mac is to install Windows. To help there are a variety of tools, for a start there is Bootcamp which is supplied by Apple and ready to go on all new Macs. Bootcamp allows you to "dual boot" - so you can choose Windows or OSX but you have to reboot to switch.

Other tools like Fusion and Parallels allow you to run Windows Applications in a window inside OSX. Some of these tools are free and some paid for but they all need you to buy or have access to a Windows licence (about £80). If you want or need to use several Windows programs running real Windows is the way to go. 

Overall, there are tradeoffs around cost and performance. Bootcamp is my personal favourite, you get the full benefit of a retina display and Windows runs brilliant on the nice Mac hardware and I don't find the swapping back and forth too upsetting. 

If you have Windows installed just install Nuno from the usual Nuno download page

Beta Release

This is a beta release! So please download it and give it a try. There's a bunch of ways to give us feedback including the feedback button on the download page.

There's more about what a beta release means in my previous blog post. 


Be warned that the download is fairly large (1.6 GB) and I recommend you start with at least 10 GB spare on your disk because it is a compressed disk image that expands out and then needs some elbow room in which to work.

(Really you should have way more than 10GB free if you want your Mac, or Windows PC, to run nicely.)

If that's ok click the link: Download Nuno_3_2_71.dmg

Depending on your connection that download might take some time - when it's done and you double click it it will whirr a bit whilst it uncompresses and then present you with the familiar "drag into Applications" install.

Click the Nuno icon and drag it into Applications.

When it's done you can run Nuno_3_2_71 from the Launchpad or from Finder like any other app. First time around Wine will do some setup - it only needs to do that the first time you run it.

Now you should see Nuno ready to activate. If you have made a Nuno account on the website or by using Nuno on a PC you already have an account or you can create on from here. After you have activated Nuno it will unlock the charts for UK waters. You can now browse the charts, create routes and so on. 

Connecting a GPS

Connecting a GPS is less automatic that it is when using Windows and worse still it (currently at least) involves typing commands into a terminal (there's some 1970s mainframe software lurking under all that the lovely usability.)

We're sorry that this bit gets a little technical and we might do something to smooth it over. Let us know how you get on.

This stuff applies to AIS as well - it's really just about connecting a device that can produce the NMEA text.

First step is to connect the device to you Mac. This will either just work or you can follow the manufacturers instructions. I connected a Blue Next bluetooth GPS by going to Preferences > Bluetooth and then turning bluetooth on a pairing with the device. Then I went to the Terminal (Launchpad > Terminal) and typed:

ls /dev/tty.*

That lists out all the serial ports available and in there was /dev/tty.BT-GPS-COM7 - you can do it before and after you connect your device and spot the new one. 

What we need to do now is create a link from the GPS, in this example called /dev/tty.BT-GPS-COM7 to Windows style serial port name "COM1" in the correct place on the disk.

All the settings for the Wine Nuno are held at ~/Library/Application\ Support/com.chersoft.nuno_142963160111409/dosdevices/ on the mac. So you need a terminal pointing at that folder. So,

cd ~/Library/Application\ Support/com.chersoft.nuno_142963160111409/dosdevices/

(Copy and paste that in ;-)

Now that you are in the right place there's one more magic command to create the link

ln -s /dev/tty.BT-GPS-COM7 com1

Now when you use the "ls" command or Finder to view the contents of that folder you will see com1 in there.

Next you need to know the details about how fast the GPS/AIS transmits NMEA. Mostly this will be 4800 8-N-1 or 9600 8-N-1, that is for example 4800 bits per second 8 bits per character, no parity and one stop bit. You don't need to understand what that means just match the config to the GPS or AIS. It might be written on that actual device or in the manual. Get in touch if you need help with this.

The download is ready for 9600 baud devices 8 bits per character no parity and one stop bit.

If you need to change this there is a file to edit called SYSTEM.REG at ~/Library/Application\ Support/com.chersoft.nuno_142963160111409/ - you can carefully edit it with TextEdit. About half a screenful down there is a setting like this:

"White list"="2,COM1,9600,8,0"

Carefully edit that taking care not to replace the quotes with fancy opening and closing quotes.

For example iff you want to change the speed to 4800 that replaces the 9600. If you need to fit in with more unusual settings please get in touch.

So there it is...

Ok, that's probably enough detail for now. Plenty of people have asked for this. Sorry it took longer than we hoped (it was harder!). Hope it comes in handy.

Nuno on a Mac

by Andrew Nibbs 7 April 2015 19:58

For some time we've been working to deliver something that a lot of people have asked for, Nuno on a Mac.

The percentage of people using Macs as opposed to Windows PCs is often said to be a little over 10%. But our research and experience suggests that amongst leisure sailors it's closer to 30%. That's why we are doing it.

This will be what software companies call a beta release. A beta is a test release - not completely untested but no guarantee that everything will work for everybody (it's actually rare that any software is released with that level of confidence unfortunately, there's always such a great range of computers and configurations out there).

Releasing a beta gives people a chance to try things and for companies to get feedback, did it work? how did it work?

Beta releases are a little experimental and so not for everyone.

It's been harder than we expected. We've had to make some changes to the software to make it work, we are using a software platform called WINE. Wine is a long running software project that allows Windows programs to run on OSX and Linux. Unlike running Windows software using Parallels, Bootcamp, VMWare and so on you don't need to buy a Windows licence. It's just a download and drag to Applications.

This has ended up being one of those long promised things that has taken longer than we hoped. But it really is real. Coming very soon...

Placing Waypoints

by Andrew Nibbs 26 January 2015 20:15

I spent a good few hours with yachting and powerboat instructors this weekend. One of the things they try to emphasise to their students is that waypoints on a route should be carefully placed to make that route easy to execute. 

It's a good idea to link a waypoint to something that the person at the helm can see. This defensive approach to passage planning builds in an easy way to keep a check on the GPS feed and to make route that can be sailed even if the GPS stops for some reason. Looking out of the window rather than at a screen is safer and more pleasant as well. 

If you can ever place a waypoint so that something conspicuous is abeam you can keep things simple in planning and execution - no need to draw pencil lines on the chart and no need to take bearings with a handheld compass whilst sailing. To make this simple, Nuno draws grey lines to either side and forward in a continuation of the route leg whilst you are making a route or adjusting the position of a waypoint on a route. 

London Boat Show 2015

by Andrew Nibbs 19 January 2015 14:48

We were at the London Boat Show 2015 last Monday (12 January 2015). The trains were having a difficult time Frown so it was something of a flying visit. Hello to everyone we talked to!

Because the RYA Training Chart Plotter is now included in all RYA Training packs we spent a lot of time on the RYA stand (not all of the time was spent playing the powerboat simulator, though we enjoyed that.)

The training plotter is based on Nuno and early feedback has been good. We believe it will be a great aid in communicating safe navigation to trainees around the world.

It was around this time last year that we were getting together the agreement for CHERSOFT and the RYA to work together on this. Developing software can at times be fraught - but developing the plotter went smoothly. Thanks to everyone at the RYA for their help with that.


Happy New Year

by Andrew Nibbs 5 January 2015 16:38

Happy New Year to you all from the Nuno team!

It's about the time of year we change the name of the application.

Last year it was called Nuno Navigator 2014. This year we are going for Nuno Navigator 2015.

Best wishes for 2015...

Changing the Nuno application caption

The Black Rose

by Tim Scott-Douglas 17 December 2014 09:49

Black Rose is a 52’3” wooden gaff-rigged ketch built in 1999 at Maylandsea in Essex, UK. She was designed by her owner Michael Emmett (assisted by many good sailors) and is based on the traditional oyster fishing smacks which were to be found around the southern North and Baltic Seas three or four centuries ago. 

Michael will be visiting the Baltic again during 2015. In addition to tending to the flax sails, cast-iron windlass and varnish work, Nuno Navigator will be on board to provide continuous GPS plotting of positions on a standard laptop PC alongside some sat comms wizardry from Navidatum. The Splice M2M terminal gives Michael satellite messaging, weather forecasting and lots of other features while he is out of cell phone coverage. It also provides a GPS NMEA feed.

Tim Scott-Douglas went on a test trip down the river Deben in darkest December (0°C, 32°F) to prove the system and enjoy a weekend’s sailing. 

Michael has been sailing around the Thames Estuary all his life in all weathers and knows it like the back of his hand. He has also been to Holland, Germany, Belgium and France many times over the years but this time there will be new places to visit and changes such as colossal windfarms offshore to plan for. Easy access to the charts is essential as is communication between navigator and helm.

The WW1 compass box is just the right height!  

We started off by putting a laptop running Nuno above the chart table. Paper charts below. The paper charts are staying for now. 

Though cold it was a bright crisp December day in Suffolk and after sailing under canvas all the way down the river to Felixstowe Ferry we turned back up river with the young flood tide. 

Having passed straight by two pubs on the way down, third time lucky on the way back we managed to persuade Michael to anchor at the Ramsholt Arms for the night. 

The Ramsholt is remembered fondly by generations of sailing families spread all over the world, many of whom will never have seen it in mid-winter with a log fire blazing. A memorable evening and then back aboard for one of the skipper’s (nearly as) famous suppers.



I bet he didn’t believe his eyes at sunrise either!

by Tim Scott-Douglas 12 March 2013 12:51


We have another instance of electronic charts being suspected of a role in a marine accident. The USS Guardian ran aground at 0225 17 January 2013 (1825 UT 16 Jan 2013) on the Tubbataha reef in the Philippines and it looks fairly likely that ignorance of horizontal datum and failure to ‘maintain a proper look-out’ (IMO COLREG 1972) were to blame. There must have been a series of ignored alarms and indications that all was not right, but somehow the app (DNC plotter) was believed.

“Since DNC mapping is used for safe navigation by Guardian and other U.S. Navy ships, Navigator of the Navy Rear Adm. Jonathan White also today released precautionary guidance to all Fleet and ship commanders. White’s message states, “initial review of navigation data indicates an error in the location of Tubbataha Reef” on the digital map.

The Avenger-class mine countermeasures ship had just completed a port call in Subic Bay and was en route to Indonesia and then on to Timor-Leste to participate in a training exercise when the grounding occurred.”

The source data for Electronic Navigational Charts (ENC) as stipulated for ECDIS and presumably the imageDigital Nautical Charts (DNC) as used by the US military comes from National Hydrographic Offices and is shared by agreement between friendly powers such as UK and US. Here are some snapshots of the paper and ENC charts of the Tubbataha Reef in the Sulu Sea. The data includes centuries of observations and measurements, often with supporting notes on validity and advice on use. It is perilous to ignore the advice but in these days of an app for everything and continuous warning messages from gadgets, the critical details is often lost.

The following are all current, corrected charts which would pass any Port of Flag State inspection. They represent more than enough information for any self-respecting navigator to cross the Sulu Sea without running into anything, the cautionary notes are well-known to seafarers as can be seen here in the continuous series of chart notes on surveys dating back to 1850!


Chart 4507 1:3,500,000 Philippines to Bismark Archipelago


The vessel was on passage from Subic Bay in Luzon north of the Sulu Sea to somewhere in Indonesia to the south. Plenty of sea room to avoid the reef and in an area well known for its sensitive natural environments.

The next bit of his intended voyage would have been in the Archipelagic Sea Lanes around Sulawesi and East Timor/Papua New Guinea to take part in a training exercise.



Chart 3811 1:500,000




Chart 967 1:725,000






Chart 3483 1:1,500,000



That note on the chart say “reefs rep to extend 1.5 miles seaward 2005”




clip_image004What was he doing within ten miles of the reef in the pitch dark - the moon’s altitude was -57° at the time? It was virtually low tide but with only a metre or so range that would not have made the difference between sinking or floating.

Below: ECDIS ENC showing a point plotted using the same co-ordinates. It would be interesting to know the co-ordinates which they were working to.

clip_image002[17]Never mind faulty DNC data or 1.5 mile errors, this is an example of ECDIS assisted casualty which would not have happened if the navigating team had looked at all available sources of information. Not just charts and publications but radar, echo-sounder or even looking and listening out of the window which I am sure told a vivid story at sunrise! Where has this vital information been lost (lost may be the wrong word here as there has obviously been a decision not to include it in the data for the ECDIS or DNC apps).

There was a lot of talk about ‘smart’ vector charts (now known as ENCs and DNCs) versus ‘dumb’ raster charts (ARCS etc) some years ago and a lot of spurious assertions as to the intelligence of the data. It makes little difference if the app is running on a mobile phone, am ECDIS or a nuclear bomb-proof naval command and control system, the only intelligent element of the system is the human navigator.


Teach the navigator how to navigate, not how to use an app.


I am guessing that he was trying to go east-west through the channel about 1.52nM north but just got too close to the reef - same school of navigation as Captain Schettino of the Costa Concordia? clip_image010

It would have been no significant deviation to leave the lighthouse to port, he was only 4 nM from it when he hit the reef so he must have been able to see it out of the window as well as on radar. I don’t actually think he was show-boating as it is an uninhabited atoll and it was dark, but he chose to believe his DNC instead of everything else.


There is no ‘error in the location of the Tubbataha Reef on the digital map’, it is referenced to a different horizontal datum. Digital maps can never be any more accurate than the source data which they have been constructed from and it will be a while before the remote (from US and Europe) parts of the world are referenced to the WGS84 spheroid.

Even state of the art cutting-edge aids to navigation apps require a true understanding of how they work and safety back-up using MKI eyeball pointing out of the window.

Digital Certificate Magic

by Simon Salter 30 May 2012 17:03

Nearly all the code that comes out of CherSoft is digitally signed. You might reasonably ask ‘So what does that mean and why should I care?’. Well, the signature provides proof that the code came from CherSoft. It also proves that the code has not been tampered with. So, not only can you be sure that you are getting exactly what you think you are getting but also that nothing has been added (like a virus) or taken away or fiddled with. This is actually a pretty strong guarantee. It is also pretty important. In fact it is considered so important that most of the requirements for handling and checking digital signature are built right into the Operating System.

Here is some technical stuff. It is easy to copy and edit files – so how do digital signatures prevent tampering? The clever bit is the use of asymmetric cryptography. Now the math behind this is a bit evil and well beyond me, however the practical upshot is that it is possible to encrypt something with a private key that can only be decrypted with a public key (a key is a string of digits that is used in the encryption algorithms). You can’t use the public key to work out what the private key is (that’s the asymmetry bit). Signing the code involves creating a digest and then encrypting this with the private key. A digest is  a summary of the code which will always change if the code changes. Imagine taking every 100th letter from a book. If the book changed then the sequence of letters would change. A digest works (very nearly) like this. It is much shorter than the whole book so it can be encrypted or decrypted quickly.

So if we give you our public key and sign the code using our private key then you can use the public key to be sure it came from us.

How do you get our public key? Easy – we put it into a certificate. This is a file which contains some information about us (CherSoft), an expiry date and our public key. When Windows checks the files before installing them it looks for a signature and checks it against the certificate. The certificate is appended to the code but you can, if you want, download a copy of it here.

Now if you are paying attention then you should be asking ‘ah ha, but how can we tell the certificate is genuine?’. Maybe you have landed with some virus ridden code and they supplied a certificate with it as well. This loophole is closed by digitally signing the certificate. We don’t do this. Verisign do it for us. In fact we pay them quite a lot of money to do it for us. Verisign sign our certificate and then the public key to  verify that signature is stored in a Verisign certificate. Verisign are known as a Certificate Authority. They sign a lot of certificates and their public key unlocks all of them. The certificate containing imagetheir public key is known as a root certificate. You can trust it because it comes from a well know source and it is ubiquitous. If someone attempted to forge our public key certificate they would not be able to use the Verisign certificate because the private key for that is kept very private. So the certificate chain leading to a trusted root certificate is your guarantee that the code is exactly what it is supposed to be.

The CherSoft certificate is signed by an intermediate certificate which in turn is signed by the root certificate.

This stuff is a bit technical and involved. Fortunately it is also quite effective and, for the most part, handled by the Operating System (Windows) in a way which makes downloading and installing stuff safer. If you ever see a message along the lines of ‘This code comes from an untrusted source’ then you should make sure that you are confident that you know exactly what it is before going any further.

The Verisign certificate needs to be installed on your computer. So how does it get there? Turns out that there are several mechanisms of which the easiest is that the Windows Update service will do it for you. Keep Windows up to date and there will not be any problems (not this sort of problem anyhow). If you do not update your PC then a problem can arise because the one of the root certificates becomes out of date. We do see this occasionally especially on shipboard computers which never get to see the Internet from one year to the next. If your root certificate is out of date you may get to see this:


The solution is to download the missing or out of date certificates. You can get the Verisign intermediate certificate here and the Verisign primary root certificate here.

Copy the information for the Certificates as explained on the web page. Then paste them into plain text files (use notepad) and save it to a file whose extension is .cer.  Follow the instructions to create a .cer file for each missing certificate. Copy the certificates to the PC. Right click and choose ‘install certificate’. This requires Admin privileges. Choose ‘Automatically select the certificate store…’ when asked and accept all other defaults.

If you want to check signature on our code manually then download the Nuno Navigator installer and right click on the file (called nunonavigator.exe). Click on the Digital Signatures tab.


Click on the CherSoft Ltd signature and choose details.