Updated October 2024.
When the ILCA Rule 22 change came into effect in 2018 allowing the use of electronic compasses, the Raymarine MicroCompass (more commonly known as the ‘TackTick’) quickly became the default choice amongst most of the top sailors – driven in part by the fact that when the rule change came into effect it was, alongside the Nautalytics simple compass, the only choice. Around a year later the Velocitek PRISM was released – a state of the art compass . Now (8th October 2024) a new compass - the SailTeck - has just been added to the list of ILCA Class legal compasses.
Above - left to right - Raymarine MicroCompass; Velocitek PRISM; SailTeck. All shown on the optional CarbonParts mounting bracket.
How do you decide between these four ILCA Rule 22 approved compasses? This article looks at the factors involved, but first why choose an electronic compass? Over the last 6 years the majority of sailors have moved from analogue to electronic. At the Paris Olympics all 20 medal race competitors were using either the PRISM or the TackTick. Electronic compasses are smaller, lighter, but it is the ease of reading that is the main reason – the digital display is much clearer than the graduations on an analogue compass, isn’t subject to the variation dependent upon viewing angle, and is faster to respond to heading change. All these lead to electronic compasses having greater useable accuracy which make it far easier to see heading changes.
So, what are the factors that need to be considered in deciding which electronic compass is right for you?
MODE – The first and maybe the most important factor is whether you want to use your compass in tactical or heading mode. The vast majority of analogue compasses used on the ILCA had a tactical scale (normally with a secondary 0-360 scale), which divided up the 360 deg scale into 20 or 24 segments. This in theory, gives you the same or similar number on either upwind tack meaning that it easier to remember – for example 2 on starboard/2 on port (for the Plastimo), or 2/12 (for the Silva/Nexus). The secondary 0-360 scale helped with head to wind and line bias. These analogue compasses assumed an 90 degree angle between tacks. In theory fine, but the tacking angle on the ILCA is dependent on the wind strength, is affected by wave skew and any ‘tide wind’ generated by current flow. So your tacking angle may not be 90 degrees and may be also skewed relative to the true wind direction from one tack to the other.
The TackTick and now the SailTeck are the only two compasses ILCA approved electronic compasses to offer a tactical mode, and the tacking angle can be adjusted on the water to get the same numbers on each tack. However, it still assumes a constant angle from one tack to the other, so if there is skew from one tack to the other the numbers displayed won’t reflect the true wind direction. In tactical mode the sensitivity can be adjusted, with most sailors choosing 5 degrees to avoid being distracted by minor shifts.
Some top sailors use the TackTick in tactical mode and others in heading mode. However, I believe that the complexity of using tactical mode simply and effectively, especially when electronic compasses offer greater useable accuracy, has resulted in more sailors moving from tactical mode to heading mode.
Heading mode displays the bearing that the boat is travelling on, so the numbers on one tack are very different from the other and as a result there are two ranges of numbers to remember (or write on the boom)! All four compasses offer heading mode. One potential downside of heading mode on the TackTick, PRISM and Nautalytics compasses is that they display 1 degree heading changes which means that in reality the display is changing a lot. You need to make sure that you are not looking at the compass too much! The PRISM compass does have an adjustable damping rate to help this aspect – the greater the damping value the smoother the heading change will be, as it slows down the response to a change in heading - this is especially important in large waves. The SailTeck compass is unique in that you can adjust the step size from 1 to 5 degrees to avoid being distracted by minor shifts.
TIMER – The rule change also allowed the use of a countdown timer to be integrated with the compass. This is a feature that is included in the TackTick, Nautalytics and SailTeck compasses. The timer on the Nautalytics and SailTeck is simple to use, with a sync function that syncs down to the next minute like most sailing watches. However you may find using the timer mode on the TackTick confusing as the sync function works differently (it syncs to the nearest minute, so it may sync up rather than down). Some people use the timer functions on these two compasses but when the timer is running you can’t see heading information unless you manually change modes. When the timer reaches zero the TackTick compass reverts to the tactical or heading mode that you were in. The Nautalytics reverts to its heading mode. The SailTeck is the best if you want an integrated timer function. It has a two line display, so that you can see the compass function on the top line of the display, and the countdown on the lower line.
DISPLAY – The size and readability of the display is another important factor. The relatively small display on the TackTick probably reflects the age of the design. The viewing angle is also quite small meaning that if you are either sitting in the cockpit in very light airs and looking down, or doing a head to wind and looking straight at the compass from the middle of the cockpit, you will find it difficult to read. The display on the PRISM is both larger and has a far better viewing angle and a non-reflective coating. The display size on the SailTeck is also larger and similar in size to the PRISM. The single very large display on the Nautalytics is probably the clearest, but it is a large compass in comparison with the lower profile, sleeker TackTick and PRISM.
If you sail using polarised sunglasses the display on the TackTick is like a lot of LCD’s, unreadable. Only the PRISM, SailTeck and Nautalytics are compatible with polarised glasses.
BATTERIES – All three compasses have inbuilt batteries recharged via solar cells. The Nautalytics batteries are cost effectively replaceable. The earlier PRISM compasses had replaceable batteries. From early 2021 to mid 2023 PRISM compasses were totally sealed and batteries are not replaceable. The latest generation of PRISM compasses have a USB charging port as a backup in case solar charging hasn't been sufficient to keep the battery charged or you have had it stored away for months. The SailTeck compass relies on an oversized solar cell to ensure that it stays charged even in poor sunlight.
MOUNTING – From a mounting perspective, for the popular TackTick there are a number of mountings available from third party manufacturers such as CarbonParts. The SailTeck compass will also fit the CarbonParts EC2 mounting. For the PRISM mountings are available from CarbonParts and Velocitek. For the Nautalytics the manufacturer offers a mounting. Most sailors choose to mount the compass as far forward as possible without fouling the vang fitting or deck blocks, with the control lines running through the mounting so that if it does become dislodged during sailing the compass stays on the boat! If you want to mount it in front of the mast, attach a security line or, if you run your centreboard elastic to the bow eye, pass that through the mount. Most mounts attach using 3M DualLock – best described as a sort of industrial strength Velcro – it really works.
So how do you choose between these electronic compasses?
About Southeast Sailboats…
Southeast Sailboats is a leading supplier of world class control line systems and electronic compass / mountings for the ILCA/Laser. We supply the PRISM, SailTeck and TackTick ILCA Rule 22 compasses and associated mountings and we deliver worldwide.