Navigation and Electronics

Navigation System Overview

Our navigation system is a combined network of Furuno devices connected to Garmin and other brand devices in multiple networks across the boat – we have traditional boat devices (such as an MFD and Garmin GMi10 displays), PC’s, iPads and iPhones and TV monitors, all of which are connected and talk to each other.  By default, the information here gets quite technical – however if any of our readers are interested in what we’ve done and would like to discuss it, then don’t hesitate to email us or contact us via social media.

There are two navigation stations – one at the helm using a Furuno TZT14 14″ multi-functional display which is fitted to the cockpit table using a Scanstrut pod.  The pod allows the MFD to be swivelled to any angle so it can be viewed from either wheel as well as from the cockpit seating area when cruising.  The second station is down below at the chart table and is based on an Intense PC – a very small, high powered i7 PC which runs entirely on 12v.  The PC is connected to an HDMI switching system which allows the screen output to be directed to the PC monitor (a cheap HP LCD monitor, which also runs entirely on 12v) or to either of the two TV screens in the boat.

The two stations are connected together via local area networks allowing sharing of charts and data, sharing of routes, control of the boat from either station on auto-pilot. Routes and marks can be created at the chart table and transmitted at the click of a button to the helm, from where they can be sent to the auto-pilot (they can also be sent DIRECTLY to the auto-pilot from the chart table but I’m banned from doing this – after I did this by mistake and send the boat – and Ed – in a spin 🙂 !!

We have three local area networks onboard:

  • NMEA2000 backbone – to which all the NMEA devices are connected from multiple manufucturers including Garmin, as well as the TZT (via it’s NMEA interface) and the PC (via an Actisense NMEA to USB PC interface)
  • Furuno NavNet – which connects the radar, the TZT and the PC
  • Ethernet LAN – standard TCP/IP local area network managed by a ProRoute GEM 4G/WiFi router which provides normal network services such as printing, data sharing and internet

The navigation software we use is Maxsea TimeZero Navigator v3 which runs under  Windows 10 (or lower) on the PC based system and Windows 7 on the TZT (although Windows is invisible other than when starting or shutting down the MFD).  We use Jeppesen CMap charts – but TimeZero can use various electronic charts including Navionics.  The software supports routes and tracks, creates automatic logbooks, weather overlays with downloaded GRIB files, departure planning and route planning with safety check, radar overlay, AIS inputs – including an API to MarineTraffic, target tracking (AIS and MARPA), overlay of cruising guide data from ActiveCaptain, personal image databases and annotations, anchor alarm, alarmed boundary lines, depth alarms and much more.  The software takes input from the Furuno NavNet (in our case radar and interface between the PC and TZT) as well as from the NMEA2000 and NMEA0183 networks.


Our radar is a Furuno NavNet 3D 19″ Digital Radome – nothing too special about that although it’s a step better than the usual Raymarine or Garmin units generally used on leisure boats and generally considered best in class.  What is special is the modification that was made to the Furuno software to allow it to output via ethernet and thus be viewable on the PC as well as on the TZT. This modification had been developed by Furuno in Germany locally but was not being used widely by Furuno in general – the UK company and the French company (both of whom we were working with) refused to do the modification which would allow us to configure our network as we wanted to.  We therefore took delivery of the unit from the UK – and then sent it on to Furuno in Germany who made the modification.

The installation and configuration had to be done by us – much to the horror of Furuno themselves once we reached Croatia and needed technical support!  They insisted that the system first had to be commissioned by Furuno – so their local technical support person came on board and gave us an A1 clearance for the quality of the installation (thankfully …!!).  They did teach us some valuable tricks on how to make best use of the capabilities – and also made some adjustments to the configuration to improve what we had done.  The Furuno radar as capable of picking up a seabird on the water – and differentiating it from the waves around it … the demonstration we received of this from them was very impressive.

The dome itself is mounted on the mast in between the first and second spreaders.  We use a Scanstrut levelling mast mount which allows the radar to remain flat at all times, even when heeling, so the image is always steady.

Chart Table Navigation Station

At the chart table we have a PC based navigation system using TimeZero, as mentioned above.  The chart table area has two PC’s so we can keep the navigation system isolated from normal office applications and web browsing, which could cause conflicts with software.  Both PC’s are Intense iPC3 machines, supplied by Tiny Green PC – these units run completely on 12V and are designed to operate across a wide temperature range, running 24/7 if necessary.  The units are used in a lot of industrial applications such as vending machines and black box commercial environments.  They are not cheap – coming in at around £1300 each including VAT – but are ideal for the marine environment.  They do not have any fan cooling but instead the case has integrated cooling through a complete cover of “fins”.  We have also used a SSD (solid state hard disk) which has no moving parts, so the machine is ruggedised for marine conditions.  The units are both equipped with Intel i7 processors – the office PC with a 7th generation and the older nav PC with a 3rd generation.  Both units have loads of USB ports – 4 at the front and 8 at the back as well as 2 HDMI ports, audio ports and coms ports.

The second PC was added in 2017 following issues with the upgrade to Windows 10 and conflicts last year between the office applications and the navigation applications.  We have had a technical build fault with the new one and it has been returned for replacement to Tiny Green PC – in the process of resolving this issue, we have some disappointments with them as their business strategy has been changed to focus on major users (50+ units purchased per annum) and initially they were not very responsive to our support request.  Eventually, when Ed sent a LinkedIn message directly to the company owner, they agreed to swap out the machine but explained they were not really interested in the future to deal with small consumers – in the future we will purchase this equipment elsewhere as it is manufactured in Israel and can easily be sourced elsewhere.

Both PC’s are connected to the TCP/IP LAN and have access to the internet via the 3G/4G router using ethernet – this also allows data sharing between the two PC’s as well as other laptops using the same network on WiFi with shared drives.  The two PC’s share a cheap 22″ HP monitor – we trawled through PC World and looked at all the power specification labels on the monitors to look for one which operated on 12V and simply removed the transformer which came with it for normal use at home, and hard wired it into the 12V system.  Both PC’s also share a cordless mouse and keyboard – standard stuff from PC World.  The sharing is achieved using a KVM switch (short for “keyboard, video and mouse”) but the setup is more complex than just one switch for the two PC’s as the video output from either or both PC’s is also capable of being sent to either or both of the TV screens in the saloon and the forward master cabin.  This was achieved by adding two Neet HDMI splitters and a whole load of HDMI cables and adapters!

The Nav PC has a second ethernet connection to the Furuno NavNet network which allows communication with the TZT at the helm station and the reception of the radar images from the radome.  The Actisense NMEA2000 PC USB Gateway connects the PC to the NMEA network via a USB port from where it receives all the normal boat instrument data into the TimeZero software.  In addition, there is a direct USB connection to the Digital Yacht AIS unit, which is only required for the purposes of configuration of the system (which you don’t do very often!) and for trouble shooting the unit – AIS signals themselves are sent over the NMEA network via the Actisense.  The Nav PC also has the NMEA Router software installed which runs constantly in the backgroud and transmits the AIS signals we send and receive via the internet to MarineTraffic.

The Office PC has a standard Windows 10 installation and Microsoft Office 2013 along with other bespoke and standard office software applications – in principle, this is just a normal PC where we can install whatever we want to.  It is connected to a cheap HP P1102W laser printer by USB – although the printer will also work on WiFi if required.

At the chart table, we also have a fixed VoIP (voice over IP) Linksys phone handset which connects to our Asterisk FreePBX telephone server back at the office in the UK (which, by the way, we also built ourselves) – enabling us to “pretend” to be in the office or at home, when actually we’re way out on the water!  As long as we have a good internet connection it works just like a normal phone line, at no cost for many calls and low cost for others.

All around the chart table are all the ships monitoring systems and remote controls and switches for all the systems on the boat.

Cockpit Navigation Station

At the helm, we have the Furuno TZT14 MFD which serves as the main navigation system when we are underway.  It is a very large screen for a small-ish sailboat but we found it very important to have good visibility and a high quality touch screen.  The screen is housed in a Scanstrut pod, which pivots and turns in all directions – allowing the screen to be used from either of the wheels or from the cockpit seating area.

The TZT is connected to the Furuno NavNet network for connection to the PC and to the radar and also to the NMEA2000 backbone to receive the instrument data from all the instruments on the boat, regardless of the manufacturer.  It has a “black box” version of Windows 7 and runs the TimeZero software, using the same charts as the PC station.  The screen has many screen split options – so can operate with navigation and radar in separate windows, or with an overlay – and can also take inputs from cameras or other devices.  In our case, we have installed the Echopilot Forward Looking Sonar as a camera and when it is running, we split the screen to show the sonar images separately.  With hindsight, we would not do this – the FLS does not operate well with the high resolution TZT screen which results in pixelated FLS images.  If we had space at the helm, we would install a separate small MFD solely for the sonar – so this was a learning point.

The boat was delivered with Garmin GMi10 displays – these were not entirely necessary as the TimeZero on the TZT allows for sidebars both left and right which provide all the same information and can be configured as you wish.  We prefer, however, to use the GMi10 displays for immediate need data – wind analogue (speed and direction), speed/log and depth so you don’t have to go searching on a busy screen for the urgent information you need.  We added a third GMi10 just because there was a gap – to fill up the space.

At each wheel, we have a Garmin GHC10 unit which controls the auto-pilot.  The system came with just one unit at the starboard side – but we found it ridiculous that it was only possible to control the auto-pilot from one side of the boat, when you would be steering from both depending on the tack.  The FLS control is only at the starboard side – as are the engine controls and bow thruster controls.  All these instruments are only used when running under engine so duplication was not necessary.

The Garmin VHF DSC radio handset extension is mounted centrally on the end of the table so it can be reached from either helm or from the cockpit seating – the main VHF radio is down below at the chart table.  We also have an extension handset for the electric windlass/chain counter at the starboard helm – this is invaluable when anchoring so Ed can see how much chain has been deployed – or how much is still on the ground when we are recovering the anchor – and make smooth decisions about when to motor the boat.  We installed this second unit after the first season as a result of med mooring on town quays where you need to drop anchor in the harbour, and then reverse and tie up on a dock at the stern.  With only two of us on board, it was impossible for me to pay out the anchor chain at the bow in the required manner, and then get to the stern in time to throw lines to a helper on the quayside.  Our approach now is that I launch and set the anchor from the bow and then immediately return to the stern to organise the lines – Ed is able to continue paying out anchor chain while we reverse.


AIS – short for Automated Identification System – has been around for a while but until recently was mainly used by commercial ships.  There are two classes of AIS – Class A is used by commercial vessels and is mandatory equipment for these ships.  Class B was introduced more recently and is a simpler form of the technology, used by leisure vessels in growing numbers.  The system transmits ship data – identification (MMSI, call sign and name) as well as it’s speed and course data – class A also transmits destination data.  The signal is transmitted over VHF and picked up by the VHF antenna – normally you need to have a 2nd VHF antenna for AIS, but we have used a powered splitter which allows us to use the same aerial but split the VHF and AIS signals and send them to different instruments in the boat.

AIS is a wonder ….. it allows you to see ships coming miles and hours away and to calculate their course towards you, with an instant and constantly updated CPA (closest point of approach) and TCPA (time to closest point of approach).  This tells you how close the ship will come to you, and how long it will take that to happen.  You can set the system to the distances you are comfortable with – we set ours to a nautical mile – and you can configure the TCPA line to the amount of warning you want to have – we set ours to an hour.  On each ship, we will therefore see a line for their course which shows us where they will be in one hour – and the alarm will sound if any ship is going to be closer than a mile to us within the next hour.  When doing night crossings, or sailing on auto-pilot, this is invaluable – you don’t have to action the warning, but at least you can keep an eye on what is happening.

AIS also allows you to make much better decisions for collision avoidance – particularly in busy areas where you may have ships all around you.  You can easily take the decision whether you can out-run and get in front of a ship safely or not.

We have an Digital Yacht AIS transponder – which means it sends signals in both directions, both to receive data from ships around us and to send our own data to others making us fully visible to any ship.  One of the issues with sailboats, and ANY small plastic leisure craft, is that the radar trace is small – even with a strong radar reflector – so AIS is another safety device to make us visible.  Many leisure yachts choose not to transmit their own signal, but to fit just a receiver so they can see others.  In our opinion, this takes away a lot of the safety benefits of AIS – although of course it does mean you can go “incognito” and people can’t track where you are!  Our AIS is hard wired to the 12V system – so it is always on – the transmissions do not get switched off when we turn off our navigation system.  We chose to do this because we wanted to be as visible as possible on anchor at all times – however, we did fit a “go dark” switch which is solely for the transmission so we are able to stop sending signals if we wish.  We have never actually done this in the Med, but we did foresee a possible situation that if we were in a dangerous area, we may not wish to attract criminals while laying on anchor!

To be clear – AIS does NOT replace radar – it is a different tool which can really only be relied on to deal with commercial shipping, because leisure boats are not required to have it installed and the majority of them don’t (we estimate only a maximum of 10%).  You can just as easily hit another yacht or fishing boat as a commercial ship – so you need to use both radar and AIS when sailing at night, in fog or on auto-pilot without 100% attendance at the helm.

Forward Looking Sonar (FLS)

The FLS is a tool we have never seen on any other sailboat – but it is something we have installed on our previous motor yachts and find to be an invaluable tool for coastal cruising.  We think it is even more important for a sailyacht, where you have bigger draft issues – Liberation draws about 2.5m with it’s lowered waterline (due to weight!) and it’s transponders and most similar size yachts will draw at least 2m.  When coastal cruising you often want to take a short-cut through an area with hazards – or you want to anchor in a lovely bay but are not sure of the depths and can’t trust the chart.  There are also situations where there is an isolated hazard (such as a rock) and you can’t see where that is exactly when making your anchoring decisions.  For those sailing in the UK or Croatia, for example, this will seem a bizarre comment ….. they are all marked with Isolated Danger Marks or Cardinal Markers aren’t they?  NO NO NO!!!!!  In Greece and Turkey at least they don’t know the meaning of these markers!  Buoyage is not what you would expect and the charts are also of varying accuracy as they are often very old – so you have to rely on your own eyes, electronics and judgement.

We have fitted EchoPilot Platinum Forward Looking Sonar (FLS) – we researched this intensely as there are not many affordable solutions on the market – this was basically the only one!  Manufacturers like Garmin, Raymarine and Furuno will all try to sell you a fish-finder – which is the closest instrument to an FLS that they make.  Whilst this does have similar functionality in some ways, it is not the same thing.  The only other options available at the time were massive commercial systems, costing tens of thousands of pounds.  Since we purchased the boat, we understand that a number of companies are now offering proper FLS products – we have not looked at or tested any of these but there is a recent review of them done by Practical Boat Owner magazine.

Our FLS uses S-Video to output to the Furuno TZT at the helm – when we need to use it we create a split screen and the FLS output appears in the small screen.  This is not ideal – and not a solution we would opt for in the future.  The resolution of the FLS output is far lower than the TZT and as a result, the screen is blurred and pixelated – we have played with this a lot and have the best we can get, but in future we would use a separate dedicated screen.  Despite this, we can see a picture of the sea bed in front of us and identify rocks and low points which enable us to navigate safely through suspect areas.





Practical Uses of the System

In a practical sense, this configuration allows us to:

  • Do all the usual electronic navigation tasks – see where you are, what is around you, depth of water, boat speed, heading …… this can be done at both stations separately, so while we are underway Ed uses the TZT at the helm but at the same time I can be at the chart table looking on a wider view of where we want to go and exploring the places on route and the destination.  When I find somewhere I think we should anchor, I can create a mark on the PC and send it to Ed in seconds so he can drive the boat there.  I can also check up on what he’s doing and where he’s going!!
  • When we want to plan a route for a day rather than just wandering aimlessly, this can be done on the PC with a mouse and keyboard and easy zoom in/out as well as automatic route checking to make sure it doesn’t cross land or hit any obstacles.  You can define your own safety zones – such as the minimum depth of water you are happy to cross.  It is so much easier to do this on a PC than on a touch screen MFD and it can be done in the comfort of the cabin in the evening.  When we’re happy with the route, it is sent to the TZT at the touch of a button and Ed can activate it on the auto-pilot.  We do this on “flat” days where we are just getting from A to B on the engine – Ed does not need to sit at the helm then, he can relax on the cockpit seating – swivel the TZT around and let the software do it’s thing.  Routes can be modified on the fly on the PC or the TZT and resent – just move the waypoint, resend and reactivate the route.  Danger here … don’t fall asleep 🙂
  • The AIS transmitter alerts of any approaching vessels and we have set our safety distance to 1 nautical mile as we don’t like to come any closer to large ships and ferries if we can help it.  The alarm line is an hour out – so we have plenty of notice (with an automatic alert) of when we need to take action either to just monitor the situation or the re-route.  At night or in busy areas with leisure boats (without AIS) we can do the same thing with the radar – and this can be done from the comfort of the cabin on night passages if you wish.