Nav station essentials

On board navigation systems have evolved to the point that they are common place on almost every level of racing yacht. This includes Med Cup TP52s, offshore “thoroughbreds” and club cruiser-racers. There are many reasons why these systems are so popular including that they aid the decision making process; provide additional safety; and enhance the performance of the yacht, regardless of the competition level.

This article looks at various levels of competition, what navigation system is required and/or desirable for that level, and how that system can be achieved. The advent of low cost tablets has made many of these systems more desirable. This is so because more tactical information can be made available from a below deck nav station up onto the deck. Yachting is moving quickly to a more technical, perhaps scientific approach. Whilst it may be possible to achieve the same result using more traditional “feel” methods, this new approach means sailors can better understand what worked and why. This means they can more quickly and accurately tweak what they are doing, allowing for faster development and repeatability.

One Design, Dinghies and Skiffs

Even at the simplest, purest level of our sport electronics are now common place. A “simple” electronic compass now provides tactical information such as lift and header tracking either by an easily tracked +/- digit, or a simple graphical system. Many class rules prohibit the use of GPS units, meaning sailors can only use magnetic devices. However, those too have become more sophisticated in recent years. Big advances in GPS technologies, both in accuracy and refresh rate, allow more and more functionality. Many yachting-specific GPS devices now provide distance to start line alongside a countdown for pre-starts, automatically switching to a race display with speed, heading and a graphical lift / header bar.

So how can these devices help in a two- or three-person one design yacht? It is true that the team could make all the same tactical decisions with a simple wind indicator and card compass. However, these technological advances mean there is no need for sailors to track wind shifts in their heads. Instead, they can now tell quickly and easily if there are any wind changes and to what degree.

For the next level one design sailor, or those training for Olympic campaigns, there are even more tools available. There are now camera systems that can monitor and measure rig bend, sail shape and more. These systems allow sailors to evaluate rig setup changes in terms of a quantifiable performance gain or loss. The net goal of all of these systems is to provide the sailors with a set of target settings for each wind speed. The hope is that sailors will spend less time during races changing gears and more time going fast from the outset.

Club Keel Boat Racing

Companies such as B&G, Garmin and Raymarine are now producing instrumentation packages that are quite comprehensive in their functionality. Each now offers a way of linking a tablet directly to the main CPU (aka the “brain”) of the system without the need to run fully-fledged tactical nav software. Each has components the quality of which could only be dreamed of by the top America’s Cup teams 15 years ago.

So what does a standard club keel boat need, and which level in the wide range of options should owners be looking for? To answer these questions, consider both the likely course on which the boat will be racing, and also the tactical output you would like to achieve. For a yacht racing on a lake with few obstacles to deal with, where local knowledge of the surroundings may be better than the available charting, it may be more cost effective to leave out the chart plotter for instance. However, for a yacht that is likely to do regattas at another club, on unfamiliar waters it is likely to be a benefit to have the chart plotter.

Perhaps the biggest influences on the level of system to be considered are the accuracy of the data and the integration between components. Will the system be required to feed navigational or tactical data from Expedition or Deckman to a display? Does the true wind direction (TWD) need to be calibrated to the highest level? It is likely that the owner will employ a performance analysis service? All of these dictate which system should be selected.

One simple improvement which can be made is to install a better compass with a higher accuracy and refresh rate than that usually integrated into the GPS unit. This is because the compass is usually the main input of any system to allow TWD to be calculated. The faster the refresh rate, the quicker the system can provide a truly settled TWD after any manoeuvre.

The next most important components of any system are usually the paddle wheel and mast head unit. Again, these contribute to the quality of the data which can be expected from a system. Many club racers are now seeing the benefit of utilising a performance analysis service. These services help devise a set of targets for boat speed and true wind angle (TWA) to give the best velocity made good (VMG) upwind and downwind. Many other variables such as optimum heel angle, fore and aft trim, and rig settings can also be derived. This means, as mentioned earlier, the known fast setting for each true wind speed (TWS) can be determined more quickly.

Grand Prix

Grand Prix racing yachts, such as the Med Cup TP52’s and Mini Maxi 72’s take the basic club level racer and give it a healthy dose of next level ninja technology. Climbing aboard one of these yachts as a navigator can seem very daunting at first. Many systems are highly customised and built upon industrial PLC embedded computers rather than consumer-level black box setups with which navigators from club level may be more familiar.

The purpose of any system for Grand Prix racing is the same as for club level racing – to go as fast as possible in any conditions and know what settings will achieve this. The difference being that to be more scientific at this level, the teams need faster, more accurate data. Many systems now use military grade GPS units, helicopter intertia moment units (IMU) as compasses and gyros, and high end processes capable of refreshing an order of magnitude quicker than an off-the-shelf solution. All electronics report what has already happened – what is key at this level is to reduce as much as possible the time between when it happened and when it is reported is the name of the game here.

These complex systems monitor many more variables than ever before. It is now common place to not only monitor forestay loads, but also side shroud loads, rudder angles, mast bend, and sail depth / draft position / twist. The navigators on board are also often logging the time that each sail is used. All of this information is logged in a database. This information is then mined so that these crews know exactly what the rig setting needs to be, which sail to use, how deep the sail needs to be, and how much twist they need in any given set of circumstances. Whilst they might not “trim to the numbers”, they certainly reference this base point many times per race. This means the team can continue to make changes to settings to maximise performance as and when conditions change.


Many of the systems remain the same whether racing inshore or offshore. This is because the end goal, to go as fast as possible in any conditions and know what settings will achieve this, is the same in both cases. However, some offshore boats use systems that have some element of motion correction. This motion correction can correct for wave action that “whips” the rig around producing artificial highs and lows in TWS and TWA / TWD. They also sometimes invest in systems with even higher refresh rates to make the difference between when something happens and when it is reported even shorter.

Offshore navigators also require a good quality chart plotter, and / or navigation software linked to a PC at the nav station. Navigators need to be on constant look out to avoid rocks, reefs and other obstacles; any system employed on an offshore yacht needs to be robust enough to ensure its key functions do not fail at the critical time.

Internet access offshore is now almost a requirement for any yacht which wants to be competitive. This allows for better quality (and sometimes more frequently updated) weather information. It also allows the yacht to track its fellow competitors. Systems which have Internet access integrated into them are often to be preferred over those which require the nav PC to be disconnected from the instruments before it can be connected to the Internet service (satellite or 4G/3G).


It is important to know at what level a yacht will compete when selecting a new navigation system. Owners and navigators should discuss this between themselves and with industry professionals, including suppliers. One common problem is that suppliers and owners/navigators often have wildly different views of what a system can achieve for any given price. Probably the most important question to ask of any supplier is what can the system not do, rather than asking what it can.

Using a performance analysis service is no longer the domain of the America’s Cup and Volvo Ocean Race alone. These services can be invaluable to all levels of sailors, particularly with a newly launched boat. Discussing system options with a performance analysist before purchase means that person can advise on what sensors and accuracy they need to help get the best results from the reports. Often the analysist can explain not only what has and has not worked previously, but also, based on their experience, what to try next. Again, this can help save valuable time.

– Ross Vickers

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